0198-0211/92/1306-0336$03.00/0 FOOT
& ANKLE
Copyright © 1992 by the American Orthopaedic FootSociety, Inc.
Range of Motion of the Foot as a Function of Age 8.M. Nigg, Ph.D., V. Fisher, T.L. Allinger, J.R. Ronsky, and J.R. Engsberg, Ph.D. Calgary, Alberta, Canada
ABSTRACT Movement of the foot is essential for human locomotion. The purpose of this paper was to quantify the range of motion of the foot as a function of age and to compare the rage of motion measurements for the foot in a laboratory coordinate system and a coordinate system fixed to the tibia. The measurements were taken in vivo using a range of motion instrument developed by Allinger (University of Calgary, Canada, 1990) from 121 subjects. The results suggest that: (1) the range of motion in general is greater for women than for men in the young adult group; (2) the range of motion in general is in the same order of magnitude for women and men in the oldest age group; and (3) the range of motion is about 8° smaller in dorsiflexion and about 8° higher in plantarflexion for women than for men in the oldest age group. It is speculated that physical activity and common shoe wear are factors influencing the age- and gender-dependent differences in range of motion. Furthermore, it has been shown that the range of motion values measured in a laboratory coordinate system and in a coordinate system fixed in the tibia are different in all directions except inversion. The differences in plantarflexion and dorsiflexion and inversion and eversion are relatively small. However, they are substantial for adduction and abduction. In all cases, the results were bigger for measurements in the laboratory coordinate system compared with the tibia coordinate system, because the movement of the lower leg was included in the measurements in the laboratory coordinate system. The data indicate that foot range of motion is different for women and men. Consequently, it is speculated that these differences may be related to possible overloading of the locomotor system, especially in sporting activities in which the loading of the foot is significant. The differences in the plantarflexion and dorsiflexion direction were assumed to influence the loading of the Achilles tendon, and it is suggested that some of the Achilles tendon problems may be predictable based on range of motion measurements.
INTRODUCTION
Motion of the foot is an important aspect during human locomotion. It may be related to performance aspects of locomotion on one side or to overuse and injury aspects on the other side. For instance, it has been proposed that the compliance of the foot is related to energy storage during locornotlon.l-" Additionally, excessive or insufficient motion of the foot has been assumed to be associated with the etiology of sports injuries.1o,15,16 Motion of the foot consists of relative movement of several bones of the lower leg and foot and is influenced by joint surface geometry, ligaments, and muscle-tendon units in and around the joint.8.22 Relative motion between the lower leg and the rearfoot is mainly determined by the motion in the joint between the tibia and the talus, the talocrural joint, and by the motion in the joint between the talus and the calcaneus, the talocalcaneal or the subtalar joint. 6,21 It is clinically difficult, if not impossible, to distlnqulsh between the movements in these two joints during normal or pathological locomotion because the talus is encompassed by the distal aspects of tibia and fibula. An attempt has been made to circumvent this difficulty by describing the complex movement in the talocrural and the subtalar joint as a movement of one universal joint, the ankle joint complex (AJC).5,25 Another approach to solve this question could be to determine a relationship between the talocrural and the subtalar joint and to use it in the description of the specific joint motion.7,2o Motion of the foot can be quantified with respect to a coordinate system in the tibia or a coordinate system in the laboratory. A tibia coordinate system (TIBIACS) is usually defined by the position of the medial malleolus, a point on the tibial crest and the tibial tuberosity.2,5,21 A TIBIACS does not include the movement of the tibia during foot movement influencing the motion of the foot in the laboratory coordinate system (LABCS). A LABCS takes the motion of the tibia into account. However, it does not allow one to distinguish between movement of the foot with respect to the
From the Human Performance Laboratory, The University of Calgary, Calgary, Alberta, Canada. Address reprint requests to: B. M. Nigg, Dr. Sc. Nat., Human Performance Laboratory, The University of Calgary, 2500 University Dr. NW., Calgary, Alberta, Canada, T2N 1N4.
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lower leg and movement of the foot due to relative movement of the tibia. The two approaches provide different results and contain different information. Both views of quantifying the motion of the foot are important and provide relevant insight into the function of the lower extremities. However, only research using a TIBIACS approach is known to the authors. It is proposed that results using the LABCS approach and a comparison between the two approaches may provide additional insight into the understanding of the function of the foot during locomotion. Motion of the foot is usually described by dorsiflexion and plantarflexion, adduction and abduction, and inversion and eversion. This subdivision assumes two rigid bodies for the leg and the foot. This assumption is not well fulfilled for the foot 11-13 and the leg,3,4 because bones of the foot and the lower leg can move relative to each other. However, using appropriate coordinate systems (for instance, for the tibia and calcaneus), this possible source of errors may be limited. The unconstrained movement of the AJC consists of three rotations and three translations. The movement in the AJC in vitro or in vivo was the subject of several studies using external fixtures supporting the foot and leg. Enqsberq" developed a 6° of freedom fixture to determine the influence of displacement and external load variations on the motion in the AJC and to determine the range of motion in vitro. Siegler and coworkers" analyzed the range of motion (ROM) of the AJC in vitro by distinguishing between contributions from the talocalcaneal and talocrural joint using a joint coordinate system approach. Because the definitions of the axes were not consistent in these two projects, the possibility for a comparison of the two results is limited. ROM studies for the AJC using a TIBIACS were performed on cadavers.":" They have the limitation that the results may not be relevant for in vivo situations. In vivo range of motion studies for the AJC 19 did not concentrate on specific age or gender groups. It may be speculated that the ROM of the foot is directly related to the actual movement of the foot during locomotion or that the difference between actual ROM during locomotion and active or passive ROM during laboratory tests may be an indicator for possible etiology of injuries. Furthermore, it may be speculated that the ROM changes with increasing age and that these changes may be relevant for the subject's potential mobility. However, changes of ROM related to age or gender have not yet been shown conclusively. If in fact the ROM does change as a function of age or gender, it may be of interest for the shoe industry to study how this change may affect the requirements for a shoe for the aging population.
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The purpose of this paper was (1) to quantify the range of motion of the foot in a LABCS as a function of age and (2) to compare the range of motion of the foot in a LABCS with the range of motion in a TIBIACS. The movement of the foot is quantified for two different coordinate systems to account for the influence of the tibia and fibula (LASCS) or to exclude their influence (TIBIACS) in the assessment of the range of motion. METHODS Range of Motion Assessment in the LABCS
Results from 121 subjects recruited from a general population were included in this study. All included subjects were physically active at least once a week and gave informed consent to participate after being informed about idea, content, and manipulations to be performed during the study. The subjects were recruited from different age groups between the ages of 20 and 80 years. Exclusion criteria for the study included artificial joints, walking aids, and any current pain conditions. Furthermore, subjects with previous major injuries which could influence gait or flexibility were excluded. Mean data and standard deviation of age, height, and weight, together with the subject numbers for each group, are listed in Table 1. Range of motion measurements were taken using a 6° of freedom machine that was developed for in vivo measurements of foot movement. 2 This construction consisted of three frames (Fig. 1). First, an outer frame that included a seat for the subject and the mounting support for the two inner frames; second, a first inner frame that fixated the leg; and third, a second inner frame that fixated the foot on a movable plate. The leg of the test subject was pressed onto the foot plate with a compressive force of 100 N. The frame allowed unconstrained motion between leg and foot as well as TABLE 1 Age, Height, Weight, and Number of Subjects for Each Age and Gender Group Included in This Study (Mean ± SO) Age group
Men N Age Height Weight Women N Age Height Weight Total N
20-39
40-59
15 26.1 ± 4.3 182.4±9.1 77.3 ± 5.7
15 50.9 ± 5.9 177.7 ± 6.3 80.0 ± 6.9
60-69
16 15 64.1 ± 2.6 73.7 ± 2.9 176.8 ± 4.3 169.9 ± 5.8 80.8 ± 10.7 76.7 ± 8.9
15 15 15 28.2 ± 4.1 48.9 ± 1.6 65.1 ± 2.9 165.9 ± 6.4 166.3 ± 4.1 161.3 ± 5.7 61.8 ± 15.0 66.6 ± 10.0 61.9 ± 8.9 30
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30
70-79
30
15 73.5 ± 4.9 159.0 ± 5.4 62.4 ± 9.2 31
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and to hold each maximal position for about 3 sec, during which time the angular displacement from neutral in the LASCS was digitally recorded (±0.1°) from potentiometers attached to the actual axes of the foot plate. For each of the six possible movements, the SUbjects were asked to perform three practice trials. After these practice trials, two trials were measured and the average of these two trials was used as the active integral range of motion measure (AIROM) in this study, describing the movement of the foot in the LASCS.
Comparison of Range of Motion Results in the LASCS and TISIACS
~OOtc As attiage Se Illbl
A' rJll-
y
Fig. 1. Illustration of the 6° of freedom measuring device." AA = abduction-adduction, DP = dorsiflexion-plantarflexion, EI = eversioninversion.
rotation of the tibia with respect to its longitudinal axis. The femur was fixed in a 90° flexion position with respect to the tibia to ensure that knee rotation and thigh movement were excluded. The LASCS was identical with the first outer frame, which corresponded to the position of the thigh. The TISIACS was defined by applying markers at the medial malleolus, at the tibial crest, and at the tibial tuberosity. With this frame, maximum dorsiflexion-plantarflexion, inversion-eversion, and abduction-adduction were measured for the left leg. The subjects wore a tight-fitting standard laboratory running shoe that was available in all sizes with no socks to minimize foot movement inside the shoe. The subject sat on a seat with the left knee at 90° flexion and was secured in the apparatus in a neutral position. The lower leg was in a vertical position and the plantar surface of the foot on the foot plate was in the horizontal plane. The leg was fixed by a V-clamp and Velcro strap around the knee and two additional V-clamps on either side of the lower leg just above the malleoli. The foot was fastened by means of Velcro straps over the heel counter, the midtarsal, and the metatarsal bones to a movable foot plate. The subjects were asked to perform a maximal active motion starting from the neutral position in the six previously mentioned directions (dorsiflexion, plantarflexion, adduction, abduction, inversion, and eversion),
The correlation between the AIROM results measured using the LASCS and the TISIACS was determined for a group of 17 subjects arbitrarily selected from the original sample. The angular displacement of the foot in the LASCS was measured in the same way as described above, using potentiometers connected to the foot plate. Simultaneously with the collection of the data in the LASCS, the angular displacement of the foot in the TISIACS was determined by using threedimensional video data (MAC system). The spatial position of the tibia was defined by markers placed on the medial malleolus, the tibial crest, and the tibial tuberosity. Following the same procedure as before, the subjects were asked to perform a maximal active motion starting from the neutral position in the six previously mentioned directions, and to hold each maximal position for about 3 sec, during which time the angular displacement from neutral was recorded. For each of the six possible movements, the subjects were asked to perform three practice trials. After these practice trials, two trials were measured and the average of these two trials was used. Using these data, the differences between the two methods were determined. Additionally, the correlation between the two measurements was calculated. Statistical Analysis
Differences between the two methods (AJC and foot) were established using a paired t-test. Multivariate analysis of variance was used to compare the results for the different age and gender groups. Differences as a function of age for each gender were determined using a one-way analysis of variance. A level of significance of .05 was used for all statistical comparisons. A correlation between the two methods was determined using a linear correlation and regression model.
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ROM AND AGING
Foot & AnklejVol. 13, No. 6/July/August 1992 Angle in TibiaCS [deg]
RESULTS AND DISCUSSION Comparison of the Range of Motion Results in the LASCS and the TISIACS
The results summarizing the differences in the active range of motion for the two coordinate systems, the AIROM and the active ankle joint complex range of motion (AAROM) (Table 2), illustrate that these two methodologies provide, except for inversion, significantly different results. The differences are substantial, especially for abduction-adduction because the determination of the AIROM using the LASCS allows for rotation of the tibia with respect to the foot. Consequently, all AIROM results based on the LASCS are higher than the AAROM results based on the TISIACS. The results summarizing the correlation between the AIROM results based on the LASCS and the AAROM results based on the TISIACS illustrate the correlation for plantarflexion-dorsiflexion (Fig. 2), inversion-eversion (Fig. 3), and abduction-adduction (Fig. 4). The
10
o - l - - - - - -.......~------10
-20
+--_-.....--+--....- ....- _....
-30 ·30
·20
-10
0
10
20
30
Angle in LabCS [deg]
I Eversion I
I Inversion I
Fig. 3. Correlation between the AIROM for the AJC (y-axis) and the foot (x-axis) for inversion-eversion measured from 17 subjects with 15 different positions per subject.
Angle in TibiaCS [deg]
TABLE 2 Differences between AIROM and AAROM Results Movement
Mean AIROM (0)
Mean AAROM (0)
Difference AIROM-AAROM (0)
P
Dorsiflexion Plantarflexion Inversion Eversion Abduction Adduction
24.7 38.9 16.9 13.4 34.3 32.3
21.2 31.4 16.5 10.4 6.9 14.9
3.5 7.5 0.4 3.0 27.4 17.3
.00001 e .0001 e .5530 .0001" .0001 a .0001"
a
339
0i---~~-+-7"'-'-'-'--,~---
-10
Significant difference on the .05 level. Angle in TibiaCS [deg]
o
Angle
+-__- .....--+--....- ....- _..~ in LabCS -40
-20
I Adduction I
0
20
40
60
[deg]
I Abduction I
Fig. 4. Correlation between the AIROM for the AJC (y-axis) and the foot (x-axis) for adduction-abduction measured from 17 subjects with 30 different positions per subject.
20 0i---------::'fF-------
TABLE 3 Correlation Coefficient and Regression Equations for the Comparison of AIROM and AAROM Results
-20
Plantarflexion -40
-_--+--....-_-.. o
+--....
-60 ·60
-40
-20
I Plantarflexion I
20
40
Angle ~ in LabCS [deg]
Dorsiflexion
Fig. 2. Correlation between the AIROM for the AJC (y-axis) and the foot (x-axis) for plantarflexion-dorsiflexion measured from 17 subjects with 15 different positions per subject.
Movement
Correlation coefficient
Plantarflexion-dorsiflexion Inversion-eversion Adduction-abduction
0.99 0.96 0.88
Regression equation" y = -0.06 Y = -1.40 y = -4.40
+ 0.90x + 0.86x + 0.34x
"In the regression equation, y stands for the results from the assessment using the LABCS method (AIROM), and x is for the results from the assessment using the TIBIACS method (AAROM).
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correlation coefficients and the regression equations are summarized in Table 3. The summarized data (Figs. 2, 3, and 4 and Table 2) indicate that, in general, AIROM and AAROM results for plantarflexion, dorsiflexion, inversion, and eversion will not show large differences; however, the results for adduction and abduction will show large differences for the two methods compared. Consequently, the AIROM and AAROM results quantify two different aspects of foot range of motion and should be well distinguished. The differences are due primarily to relative motion between the tibia and the outer frame of the fixation device. AIROM for the Foot as a Function of Age and Gender
The results of the AIROM measurements for the different age and gender groups are summarized in Figure 5. The results for the total population are illustrated in Figure 5A, for male test subjects in Figure 58, and for female test subjects in Figure 5C. Additionally, the results are summarized numerically (including standard deviation) in Table 4. The multivariate analysis of variance showed a significant change in AIROM with age for the total group for plantarflexion, inversion, abduction, and adduction, but not for eversion and dorsiflexion. The changes in the AIROM values as a function of age were different for the different genders. Male test subjects showed no significant change among the different age groups for dorsiflexion, with average dorsiflexion angles between 25.3° and 27.1°. Female test subjects showed a significant decrease in dorsiflexion as a function of age from 26.0° for the youngest to 18.5° for the oldest age group. The results for plantarflexion were similar for the two gender groups, with higher AIROM values for the youngest and lower AIROM values for the oldest subject groups. The decrease in the AIROM results for plantarflexion was about 8° over the studied age range for both genders. The results for inversion showed less than 4° of difference among the age groups for male test subjects. However, the results for inversion of female test subjects showed a significant decrease of 6.1° with increasing age. The results for eversion showed no significant change as a function of age for male test subjects, but a significant decrease from 17.2° for the youngest to 11.4° for the oldest female age group. The results for abduction and adduction showed similar results for both gender groups. They decreased as a function of age in the same order of magnitude (about 6° and 10°) for both gender groups. The finding that, in general, the AIROM values decreased with increasing age for the combined group
A
MALES AND FEMALES
ROM (dog} 50
.20-39 r:;l40-59 060-69
40
~70-79
30 20 10
dorsi
plantar
B
lnv
ev
abd
add
MALES
ROM
(dog) 50 .20-39 1':l40-59 12160-69 f170-79
40 30 20 10 0
dorsi
plantar
C
Inv
ev
add
FEMALES
ROM (dog) 50
.20-39 ~40-59
40
060-69 5170-79
30 20
/ / / /
10
dorsi
plantar
inv
ev
abd
add
Fig. 5. Summary of the AIROM results for A, the total group, for B, males, and for C, women.
was expected. However, the possible reasons for this change are not yet answered. Possible factors involved in a reduction of the AIROM values include: 1. The active muscle forces responsible for the movement are decreasing with increasing age, resulting in less strength available to perform the movement. Measurements of passive range of motion in which the individual muscular influence is excluded may provide insight into the muscular contribution to the AIROM. 2. The ligaments and the capsule apparatus are becoming stiffer with increasing age, allowing less movement in the joints. Support for this suggestion provides results quantifying the age influence on the elastic modulus, showing that the elastic modulus decreases from about 120 MPa at the age of 20 to about 60 MPa at the age of 80. 17
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Foot & Ankle/Vol. 13, No. 6/July/August 1992
ROM AND AGING
341
TABLE 4 Comparison of Active ROM Measures (±SD) with Age and with Gender and Age Group Age (men and women)"
Gender and age Men"
WomenC
N
20-39 40-59 60-69 70-79 20-39 40-59 60-69. 70-79 20-39 40-59 60-69 70-79
15 15 15 16 15 15 15 15
Dorsiflexion
Plantarflexion
25.51 25.38 22.98 22.57
± ± ± ±
6.6 5.9 5.2 6.1
44.60 40.30 38.89 37.03
25.0 27.1 25.4 26.4 26.0 23.7 20.6 18.5
± ± ± ± ± ± ± ±
7.0 5.9 4.7 4.7 6.4 5.7 4.6 4.8
± ± ± ±
8.8 7.8 6.8 7.2
41.0±9.9 40.0 ± 6.2 36.2 ± 5.6 33.7 ± 6.9 48.2 ± 5.9 40.6 ± 9.4 41.6 ± 7.1 40.5 ± 5.9
Inversion
20.61 20.70 17.14 17.05
± ± ± ±
6.7 8.0 5.8 5.7
Eversion
14.93 13.77 12.29 11.39
19.8±6.1 21.8 ± 8.2 19.0 ± 5.5 18.6 ± 5.6 21.4 ± 7.3 19.6±7.9 15.3 ± 5.5 15.3 ± 5.5
± ± ± ±
Abduction
5.1 3.3 3.2 3.3
37.81 33.22 31.65 31.29
± ± ± ±
10.1 7.6 5.4 8.5
12.6 ± 4.0 13.3 ± 3.6 13.0 ± 3.4 11.4 ± 3.2 17.2 ± 5.2 14.2 ± 3.1 11.6±2.9 11.4 ± 3.5
35.4 32.5 30.7 29.7 40.2 33.9 32.6 33.0
± ± ± ± ± ± ± ±
9.1 6.8 4.5 8.8 10.7 8.5 6.1 8.1
Adduction
34.61 29.93 27.86 27.07
± ± ± ±
9.5 9.1 8.5 7.4
33.5±10.1 32.3 ± 6.6 30.6 ± 6.3 27.7 ± 6.6 35.8 ± 8.9 27.6 ± 10.7 25.1 ± 9.8 26.4 ± 8.5
a Plantarflexion, inversion, abduction, and adduction were significantly different with age (P < .05). Dorsiflexion and eversion had a significant gender and age interaction (P < .05). b Plantarflexion was significantly different with age (P < .05). C Dorsiflexion, plantarflexion, inversion, eversion, and adduction were significantly different with age (P < .05).
3. Articular cartilage is changing with increasing age, reducing the possible motion in a joint. Changes of articular cartilage as a function of age, such as a gradual decrease in tensile fatigue properties," have been documented. However, the relationship between these changes and actual movement are not known yet. In general, the AIROM values of the foot for the combined male and female group (Table 5) decreased between 20 and 80 years of age. The relative changes were in the same order of magnitude for all six directions (dorsiflexion, plantarflexion, inversion, eversion, adduction, and abduction; 12% to 24%). However, the findings were different for women and men in the subject sample used in this study. The gender-relateddifferences can be summarized and discussed as follows: First, the reduction of the absolute AIROM values from the youngest to the oldest group was about twice as large for women than for men. It may be speculated that this may be a result of the different amount and type of physical activity of men and women, assuming that the AIROM of the foot and physical activity are related and that men in general may do more physical activity than women during their life span. Second, women showed the lowest relative reduction as a function of age in movement directions, whereas men showed the highest reduction, and vice versa. Female AIROM reductions were significantly higher for dorsiflexion and eversion, movement components which occur more likely in physical activities but only in a limited amount in daily activities. Third, the change in the AIROM results was influenced by the initial starting values. A comparison of the AIROM values for the youngest age group showed that the AIROM was larger for women than for men for all movement directions (Table 6). However, with increas-
TABLE 5 Mean Differences in AIROM between the Youngest and the Oldest Age Groups for the Total Group as well as for the Male and Female Groups Difference (young, old) Movement
All
Men
Women (0) (%)
(0)
(%)
(0)
Dorsiflexion Plantarflexion Inversion Eversion Abduction Adduction
2.9 7.6 3.6 3.5 6.5 7.5
12 17 17 24 17 22
-1.4 7.3 1.2 1.2 5.7 5.8
-1 18 6 10 16 17
7.5 7.7 6.1 5.8 7.2 9.4
29 a 16 29 34 a 18 26
Average difference
5.3
18
3.8
11
7.3
25
(%)
Differences between results for male and female groups were determined with a multivariate analysis of variance test. a
TABLE 6 Differences in AIROM Values between Males and Females for the Youngest and the Oldest Age Groups Men and women Movement
Youngest group (0)
Oldest group (0)
Dorsiflexion Plantarflexion Inversion Eversion Abduction Adduction
-1.0 -7.1 -1.6 -4.6 -4.8 -2.3
+7.9 -6.8 +3.3 0.0 -3.3 +1.3
Average differences
-3.5
+0.4
ing age, the ranking changed. The biggest differences occurred in dorsiflexion, where the AIROM values for men became significantly larger than for women with increasing age. In general, men showed in the average a smaller AIROM than women in the young adult age,
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whereas men and women showed about the same AIROM for the high age. However, differences existed in the specific movement directions for the oldest age group. Fourth, the differences between males and females in dorsiflexion-plantarflexion suggest that functional aspects may be of importance. Male and female footwear is often different in the dorsiflexion-plantarflexion construction. The use of high heel shoes by women may shorten the Achilles tendon, hampering AIROM in dorsiflexion but aiding AIROM in plantarflexion. In support of this speculation is the fact that dorsiflexion is about 8° smaller and plantarflexion about 8° higher for women than for men for the oldest age group. The possible connection between changes in the AIROM and physical activities is speculation, and the present setup of the experiment does not allow conclusive statements in this context. Experiments analyzing the influence of physical activity on the ROM of several joints have shown that physical activity increases the ROM of the analyzed joints and movements in these joints." More experiments specifically related to the complex movement of the foot may provide the necessary missing information to answer this question. Based on the findings of this study, we speculated that: (1) changes in the AIROM of the foot depend on age and gender; (2) changes in the AIROM of the foot are different for men and women; and (3) decreases in the AIROM of the foot as a function of age may be reduced with appropriate physical activity, Discussions about the "appropriate" measurement of the AIROM for the foot with noninvasive methods will continue. The method for the determination of the AIROM of the foot used in this project has limitations as outlined in the "Methods" section. However, one of the important advantages consists in the fact that the motion quantified corresponds to a motion that may be registered during actual movement. For locomotion analysis, the lower leg and the rear foot are usually treated as one rigid body. The movement of the rear foot with respect to the lower leg is affected by the relative bone movement, as described in the "Methods" section. Consequently, the AIROM measured with the selected methodology and the actual movement of the rear foot during locomotion may show some correlation, because similar variables are quantified. Currently, it is not clear how the findings of this study relate to shoe construction. One may speculate that stability of a shoe may become more important with decreasing AIROM of the foot. However, specific future studies quantifying the loading in the internal foot structures 14 are needed to provide specific answers to this question. Furthermore, one may speculate that, in general, shoes, and especially sport shoes for young
women, should be constructed differently than (sport) shoes for young men because (1) the AIROM of the foot is larger for women than for men in this age bracket and (2) the AIROM of the foot is shifted (about 8°) toward plantarflexion for women compared with men. ACKNOWLEDGMENTS
This project has been supported by a research grant from the Canadian Fitness and Lifestyle Research Institute, the Alberta Heritage Foundation for Medical Research, and a research grant from Adidas.
REFERENCES 1. Alexander, R.McN.: Elastic Mechanisms in Animal Movement. Cambridge, Cambridge University Press, 1988. 2. Allinger, T.L.: A Method to Determine the Static Range of Motion of the Ankle Joint Complex In Vivo. Master's thesis, University of Calgary, Canada, 1990. 3. Barnett, C.H., and Napier, J.R.: The axis of rotation at the ankle joint in man. Its influence upon the form of the talus and the mobility of the fibula. Anatomy, 86:1-9,1952. 4. Close, J.R.: Some application of the functional anatomy of the ankle joint. J. Bone Joint Surg., 38(A4):761-781, 1956. 5. Engsberg, J.R.: A biomechanical analysis of the tala-calcaneal jointin vitro. J. Biomech., 20:429-442, 1987. 6. Engsberg, J.R., and Allinger, T.L.: A function of the talocalcaneal joint during running support. Foot Ankle, 11:93-96, 1990. 7. Engsberg, J.R., Grimston, S.K., and Wackwitz, J.: Predicting talo-calcaneal joint orientations from talo-calcaneal/talo-crural joint orientations. J. Orthop. Res., 6:749-757,1988. 8. Inman, V.T., and Mann, R.A.: Biomechanics of the foot and ankle. In Surgery of the Foot. St. Louis, C.V. Mosby, 1973, pp. 3-22. 9. Ker, R.F., Bennett, M.B., Bibby, S.R., Kester, R.C., and Alexander, R.McN.: The spring in the arch of the human foot. Nature, 325:147-149, 1987. 10. Luethi, S.M., Frederick, E.C., Hawes, M.R., and Nigg, B.M.: Influence of shoe construction on lower extremity kinematics and load during lateral movements in tennis. Int. J. Sports Biomech., 2:166-174,1986. 11. Lundberg, A., Goldie, I., Kalin, B., and Selvik, G.: Kinematics of the ankle/foot complex: plantarflexion and dorsiflexion. Foot Ankle, 9:194-200, 1989a. 12. Lundberg, A., Svensson, O.K., Bylund, C., Goldie, I., and Selvik, G.: Kinematics of the ankle/foot complex-part 2: pronation and supination. Foot Ankle, 9:248-253, 1989b. 13. Lundberg, A., Svensson, O.K., Bylund, C., and Selvik, G.: Kinematics of the ankle/foot complex-part 3: influence of leg rotation. Foot Ankle, 9:304-309, 1989c. 14. Morlock, M., and Nigg, B.M.: Theoretical considerations and practical results on the influence of the representation of the foot for the estimation of internal forces with models. Clin. Biomech., 6:3-13,1991. 15. Nigg, B.M.: Biomechanics of Running Shoes. Champaign, IL, Human Kinetics, 1986. 16. Nigg, B.M., Frederick, E.C., Hawes, M.R., and Luethi, S.M.: Factors influencing short term pain and injuries in tennis. Int. J. Sports Biomech., 2:156-165,1986. 17. Noyes, F.R., and Grood, E.S.: The strength of the anterior
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18.
19.
20. 21.
cruciate ligament in humans and rhesus monkeys. Age related and species related changes. J. Bone Joint Surg., 58A:10741082,1976. Raab, M.S., Agre, J.C., McAdam, M., and Smith, E.L.: Light resistance and stretching exercise in elderly women: effect upon flexibility. Arch. Phys. Med. Rehabil., 69:268-272, 1988. Roass, A., and Anderson, G.B.J.: Normal range of motion of the hip, knee and ankle joints in male subjects, 30-40 years of age. Acta Orthop. Scand., 53:205-208,1982. Scott, S.H., and Winter, D.A.: Personal communication, 1991. Siegler, S., Chen, J., and Schneck, C.D.: The three-dimensional kinematics and flexibility characteristics of the human ankle and subtalar joints-part I: kinematics. J. Biomech. Eng., 110:364-
343
373,1988. 22. Stormont, D.M., Morrey, B.F., An, K., and Cass, J.R.: Stability of the loaded ankle-relation between articular restraint and primary and secondary static restraints. Am. J. Sports Med., 13:295-300,1985. 23. Weightman, B.: In vitro fatigue testing of articular cartilage. Ann. Rheum. Dis., 34(Suppl 2):108-110, 1975. 24. Weseley, M.S., Koval, R., and Kleiger, B.: Roentgen measurements of ankle flexion-extension measurement. Clin. Orthop., 65:167-174,1969. 25. Wright, D.G., Desai, S.M., and Henderson, W.H.: Action of the subtalar and ankle joint complex during the stance phase of walking. J. Bone Joint Surg., 46(A2):361-382, 1964.
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& ANKLE
Copyright © 1992 by the American Orthopaedic FootSociety, Inc.
Range of Motion of the Foot as a Function of Age 8.M. Nigg, Ph.D., V. Fisher, T.L. Allinger, J.R. Ronsky, and J.R. Engsberg, Ph.D. Calgary, Alberta, Canada
ABSTRACT Movement of the foot is essential for human locomotion. The purpose of this paper was to quantify the range of motion of the foot as a function of age and to compare the rage of motion measurements for the foot in a laboratory coordinate system and a coordinate system fixed to the tibia. The measurements were taken in vivo using a range of motion instrument developed by Allinger (University of Calgary, Canada, 1990) from 121 subjects. The results suggest that: (1) the range of motion in general is greater for women than for men in the young adult group; (2) the range of motion in general is in the same order of magnitude for women and men in the oldest age group; and (3) the range of motion is about 8° smaller in dorsiflexion and about 8° higher in plantarflexion for women than for men in the oldest age group. It is speculated that physical activity and common shoe wear are factors influencing the age- and gender-dependent differences in range of motion. Furthermore, it has been shown that the range of motion values measured in a laboratory coordinate system and in a coordinate system fixed in the tibia are different in all directions except inversion. The differences in plantarflexion and dorsiflexion and inversion and eversion are relatively small. However, they are substantial for adduction and abduction. In all cases, the results were bigger for measurements in the laboratory coordinate system compared with the tibia coordinate system, because the movement of the lower leg was included in the measurements in the laboratory coordinate system. The data indicate that foot range of motion is different for women and men. Consequently, it is speculated that these differences may be related to possible overloading of the locomotor system, especially in sporting activities in which the loading of the foot is significant. The differences in the plantarflexion and dorsiflexion direction were assumed to influence the loading of the Achilles tendon, and it is suggested that some of the Achilles tendon problems may be predictable based on range of motion measurements.
INTRODUCTION
Motion of the foot is an important aspect during human locomotion. It may be related to performance aspects of locomotion on one side or to overuse and injury aspects on the other side. For instance, it has been proposed that the compliance of the foot is related to energy storage during locornotlon.l-" Additionally, excessive or insufficient motion of the foot has been assumed to be associated with the etiology of sports injuries.1o,15,16 Motion of the foot consists of relative movement of several bones of the lower leg and foot and is influenced by joint surface geometry, ligaments, and muscle-tendon units in and around the joint.8.22 Relative motion between the lower leg and the rearfoot is mainly determined by the motion in the joint between the tibia and the talus, the talocrural joint, and by the motion in the joint between the talus and the calcaneus, the talocalcaneal or the subtalar joint. 6,21 It is clinically difficult, if not impossible, to distlnqulsh between the movements in these two joints during normal or pathological locomotion because the talus is encompassed by the distal aspects of tibia and fibula. An attempt has been made to circumvent this difficulty by describing the complex movement in the talocrural and the subtalar joint as a movement of one universal joint, the ankle joint complex (AJC).5,25 Another approach to solve this question could be to determine a relationship between the talocrural and the subtalar joint and to use it in the description of the specific joint motion.7,2o Motion of the foot can be quantified with respect to a coordinate system in the tibia or a coordinate system in the laboratory. A tibia coordinate system (TIBIACS) is usually defined by the position of the medial malleolus, a point on the tibial crest and the tibial tuberosity.2,5,21 A TIBIACS does not include the movement of the tibia during foot movement influencing the motion of the foot in the laboratory coordinate system (LABCS). A LABCS takes the motion of the tibia into account. However, it does not allow one to distinguish between movement of the foot with respect to the
From the Human Performance Laboratory, The University of Calgary, Calgary, Alberta, Canada. Address reprint requests to: B. M. Nigg, Dr. Sc. Nat., Human Performance Laboratory, The University of Calgary, 2500 University Dr. NW., Calgary, Alberta, Canada, T2N 1N4.
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lower leg and movement of the foot due to relative movement of the tibia. The two approaches provide different results and contain different information. Both views of quantifying the motion of the foot are important and provide relevant insight into the function of the lower extremities. However, only research using a TIBIACS approach is known to the authors. It is proposed that results using the LABCS approach and a comparison between the two approaches may provide additional insight into the understanding of the function of the foot during locomotion. Motion of the foot is usually described by dorsiflexion and plantarflexion, adduction and abduction, and inversion and eversion. This subdivision assumes two rigid bodies for the leg and the foot. This assumption is not well fulfilled for the foot 11-13 and the leg,3,4 because bones of the foot and the lower leg can move relative to each other. However, using appropriate coordinate systems (for instance, for the tibia and calcaneus), this possible source of errors may be limited. The unconstrained movement of the AJC consists of three rotations and three translations. The movement in the AJC in vitro or in vivo was the subject of several studies using external fixtures supporting the foot and leg. Enqsberq" developed a 6° of freedom fixture to determine the influence of displacement and external load variations on the motion in the AJC and to determine the range of motion in vitro. Siegler and coworkers" analyzed the range of motion (ROM) of the AJC in vitro by distinguishing between contributions from the talocalcaneal and talocrural joint using a joint coordinate system approach. Because the definitions of the axes were not consistent in these two projects, the possibility for a comparison of the two results is limited. ROM studies for the AJC using a TIBIACS were performed on cadavers.":" They have the limitation that the results may not be relevant for in vivo situations. In vivo range of motion studies for the AJC 19 did not concentrate on specific age or gender groups. It may be speculated that the ROM of the foot is directly related to the actual movement of the foot during locomotion or that the difference between actual ROM during locomotion and active or passive ROM during laboratory tests may be an indicator for possible etiology of injuries. Furthermore, it may be speculated that the ROM changes with increasing age and that these changes may be relevant for the subject's potential mobility. However, changes of ROM related to age or gender have not yet been shown conclusively. If in fact the ROM does change as a function of age or gender, it may be of interest for the shoe industry to study how this change may affect the requirements for a shoe for the aging population.
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The purpose of this paper was (1) to quantify the range of motion of the foot in a LABCS as a function of age and (2) to compare the range of motion of the foot in a LABCS with the range of motion in a TIBIACS. The movement of the foot is quantified for two different coordinate systems to account for the influence of the tibia and fibula (LASCS) or to exclude their influence (TIBIACS) in the assessment of the range of motion. METHODS Range of Motion Assessment in the LABCS
Results from 121 subjects recruited from a general population were included in this study. All included subjects were physically active at least once a week and gave informed consent to participate after being informed about idea, content, and manipulations to be performed during the study. The subjects were recruited from different age groups between the ages of 20 and 80 years. Exclusion criteria for the study included artificial joints, walking aids, and any current pain conditions. Furthermore, subjects with previous major injuries which could influence gait or flexibility were excluded. Mean data and standard deviation of age, height, and weight, together with the subject numbers for each group, are listed in Table 1. Range of motion measurements were taken using a 6° of freedom machine that was developed for in vivo measurements of foot movement. 2 This construction consisted of three frames (Fig. 1). First, an outer frame that included a seat for the subject and the mounting support for the two inner frames; second, a first inner frame that fixated the leg; and third, a second inner frame that fixated the foot on a movable plate. The leg of the test subject was pressed onto the foot plate with a compressive force of 100 N. The frame allowed unconstrained motion between leg and foot as well as TABLE 1 Age, Height, Weight, and Number of Subjects for Each Age and Gender Group Included in This Study (Mean ± SO) Age group
Men N Age Height Weight Women N Age Height Weight Total N
20-39
40-59
15 26.1 ± 4.3 182.4±9.1 77.3 ± 5.7
15 50.9 ± 5.9 177.7 ± 6.3 80.0 ± 6.9
60-69
16 15 64.1 ± 2.6 73.7 ± 2.9 176.8 ± 4.3 169.9 ± 5.8 80.8 ± 10.7 76.7 ± 8.9
15 15 15 28.2 ± 4.1 48.9 ± 1.6 65.1 ± 2.9 165.9 ± 6.4 166.3 ± 4.1 161.3 ± 5.7 61.8 ± 15.0 66.6 ± 10.0 61.9 ± 8.9 30
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30
70-79
30
15 73.5 ± 4.9 159.0 ± 5.4 62.4 ± 9.2 31
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and to hold each maximal position for about 3 sec, during which time the angular displacement from neutral in the LASCS was digitally recorded (±0.1°) from potentiometers attached to the actual axes of the foot plate. For each of the six possible movements, the SUbjects were asked to perform three practice trials. After these practice trials, two trials were measured and the average of these two trials was used as the active integral range of motion measure (AIROM) in this study, describing the movement of the foot in the LASCS.
Comparison of Range of Motion Results in the LASCS and TISIACS
~OOtc As attiage Se Illbl
A' rJll-
y
Fig. 1. Illustration of the 6° of freedom measuring device." AA = abduction-adduction, DP = dorsiflexion-plantarflexion, EI = eversioninversion.
rotation of the tibia with respect to its longitudinal axis. The femur was fixed in a 90° flexion position with respect to the tibia to ensure that knee rotation and thigh movement were excluded. The LASCS was identical with the first outer frame, which corresponded to the position of the thigh. The TISIACS was defined by applying markers at the medial malleolus, at the tibial crest, and at the tibial tuberosity. With this frame, maximum dorsiflexion-plantarflexion, inversion-eversion, and abduction-adduction were measured for the left leg. The subjects wore a tight-fitting standard laboratory running shoe that was available in all sizes with no socks to minimize foot movement inside the shoe. The subject sat on a seat with the left knee at 90° flexion and was secured in the apparatus in a neutral position. The lower leg was in a vertical position and the plantar surface of the foot on the foot plate was in the horizontal plane. The leg was fixed by a V-clamp and Velcro strap around the knee and two additional V-clamps on either side of the lower leg just above the malleoli. The foot was fastened by means of Velcro straps over the heel counter, the midtarsal, and the metatarsal bones to a movable foot plate. The subjects were asked to perform a maximal active motion starting from the neutral position in the six previously mentioned directions (dorsiflexion, plantarflexion, adduction, abduction, inversion, and eversion),
The correlation between the AIROM results measured using the LASCS and the TISIACS was determined for a group of 17 subjects arbitrarily selected from the original sample. The angular displacement of the foot in the LASCS was measured in the same way as described above, using potentiometers connected to the foot plate. Simultaneously with the collection of the data in the LASCS, the angular displacement of the foot in the TISIACS was determined by using threedimensional video data (MAC system). The spatial position of the tibia was defined by markers placed on the medial malleolus, the tibial crest, and the tibial tuberosity. Following the same procedure as before, the subjects were asked to perform a maximal active motion starting from the neutral position in the six previously mentioned directions, and to hold each maximal position for about 3 sec, during which time the angular displacement from neutral was recorded. For each of the six possible movements, the subjects were asked to perform three practice trials. After these practice trials, two trials were measured and the average of these two trials was used. Using these data, the differences between the two methods were determined. Additionally, the correlation between the two measurements was calculated. Statistical Analysis
Differences between the two methods (AJC and foot) were established using a paired t-test. Multivariate analysis of variance was used to compare the results for the different age and gender groups. Differences as a function of age for each gender were determined using a one-way analysis of variance. A level of significance of .05 was used for all statistical comparisons. A correlation between the two methods was determined using a linear correlation and regression model.
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Foot & AnklejVol. 13, No. 6/July/August 1992 Angle in TibiaCS [deg]
RESULTS AND DISCUSSION Comparison of the Range of Motion Results in the LASCS and the TISIACS
The results summarizing the differences in the active range of motion for the two coordinate systems, the AIROM and the active ankle joint complex range of motion (AAROM) (Table 2), illustrate that these two methodologies provide, except for inversion, significantly different results. The differences are substantial, especially for abduction-adduction because the determination of the AIROM using the LASCS allows for rotation of the tibia with respect to the foot. Consequently, all AIROM results based on the LASCS are higher than the AAROM results based on the TISIACS. The results summarizing the correlation between the AIROM results based on the LASCS and the AAROM results based on the TISIACS illustrate the correlation for plantarflexion-dorsiflexion (Fig. 2), inversion-eversion (Fig. 3), and abduction-adduction (Fig. 4). The
10
o - l - - - - - -.......~------10
-20
+--_-.....--+--....- ....- _....
-30 ·30
·20
-10
0
10
20
30
Angle in LabCS [deg]
I Eversion I
I Inversion I
Fig. 3. Correlation between the AIROM for the AJC (y-axis) and the foot (x-axis) for inversion-eversion measured from 17 subjects with 15 different positions per subject.
Angle in TibiaCS [deg]
TABLE 2 Differences between AIROM and AAROM Results Movement
Mean AIROM (0)
Mean AAROM (0)
Difference AIROM-AAROM (0)
P
Dorsiflexion Plantarflexion Inversion Eversion Abduction Adduction
24.7 38.9 16.9 13.4 34.3 32.3
21.2 31.4 16.5 10.4 6.9 14.9
3.5 7.5 0.4 3.0 27.4 17.3
.00001 e .0001 e .5530 .0001" .0001 a .0001"
a
339
0i---~~-+-7"'-'-'-'--,~---
-10
Significant difference on the .05 level. Angle in TibiaCS [deg]
o
Angle
+-__- .....--+--....- ....- _..~ in LabCS -40
-20
I Adduction I
0
20
40
60
[deg]
I Abduction I
Fig. 4. Correlation between the AIROM for the AJC (y-axis) and the foot (x-axis) for adduction-abduction measured from 17 subjects with 30 different positions per subject.
20 0i---------::'fF-------
TABLE 3 Correlation Coefficient and Regression Equations for the Comparison of AIROM and AAROM Results
-20
Plantarflexion -40
-_--+--....-_-.. o
+--....
-60 ·60
-40
-20
I Plantarflexion I
20
40
Angle ~ in LabCS [deg]
Dorsiflexion
Fig. 2. Correlation between the AIROM for the AJC (y-axis) and the foot (x-axis) for plantarflexion-dorsiflexion measured from 17 subjects with 15 different positions per subject.
Movement
Correlation coefficient
Plantarflexion-dorsiflexion Inversion-eversion Adduction-abduction
0.99 0.96 0.88
Regression equation" y = -0.06 Y = -1.40 y = -4.40
+ 0.90x + 0.86x + 0.34x
"In the regression equation, y stands for the results from the assessment using the LABCS method (AIROM), and x is for the results from the assessment using the TIBIACS method (AAROM).
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correlation coefficients and the regression equations are summarized in Table 3. The summarized data (Figs. 2, 3, and 4 and Table 2) indicate that, in general, AIROM and AAROM results for plantarflexion, dorsiflexion, inversion, and eversion will not show large differences; however, the results for adduction and abduction will show large differences for the two methods compared. Consequently, the AIROM and AAROM results quantify two different aspects of foot range of motion and should be well distinguished. The differences are due primarily to relative motion between the tibia and the outer frame of the fixation device. AIROM for the Foot as a Function of Age and Gender
The results of the AIROM measurements for the different age and gender groups are summarized in Figure 5. The results for the total population are illustrated in Figure 5A, for male test subjects in Figure 58, and for female test subjects in Figure 5C. Additionally, the results are summarized numerically (including standard deviation) in Table 4. The multivariate analysis of variance showed a significant change in AIROM with age for the total group for plantarflexion, inversion, abduction, and adduction, but not for eversion and dorsiflexion. The changes in the AIROM values as a function of age were different for the different genders. Male test subjects showed no significant change among the different age groups for dorsiflexion, with average dorsiflexion angles between 25.3° and 27.1°. Female test subjects showed a significant decrease in dorsiflexion as a function of age from 26.0° for the youngest to 18.5° for the oldest age group. The results for plantarflexion were similar for the two gender groups, with higher AIROM values for the youngest and lower AIROM values for the oldest subject groups. The decrease in the AIROM results for plantarflexion was about 8° over the studied age range for both genders. The results for inversion showed less than 4° of difference among the age groups for male test subjects. However, the results for inversion of female test subjects showed a significant decrease of 6.1° with increasing age. The results for eversion showed no significant change as a function of age for male test subjects, but a significant decrease from 17.2° for the youngest to 11.4° for the oldest female age group. The results for abduction and adduction showed similar results for both gender groups. They decreased as a function of age in the same order of magnitude (about 6° and 10°) for both gender groups. The finding that, in general, the AIROM values decreased with increasing age for the combined group
A
MALES AND FEMALES
ROM (dog} 50
.20-39 r:;l40-59 060-69
40
~70-79
30 20 10
dorsi
plantar
B
lnv
ev
abd
add
MALES
ROM
(dog) 50 .20-39 1':l40-59 12160-69 f170-79
40 30 20 10 0
dorsi
plantar
C
Inv
ev
add
FEMALES
ROM (dog) 50
.20-39 ~40-59
40
060-69 5170-79
30 20
/ / / /
10
dorsi
plantar
inv
ev
abd
add
Fig. 5. Summary of the AIROM results for A, the total group, for B, males, and for C, women.
was expected. However, the possible reasons for this change are not yet answered. Possible factors involved in a reduction of the AIROM values include: 1. The active muscle forces responsible for the movement are decreasing with increasing age, resulting in less strength available to perform the movement. Measurements of passive range of motion in which the individual muscular influence is excluded may provide insight into the muscular contribution to the AIROM. 2. The ligaments and the capsule apparatus are becoming stiffer with increasing age, allowing less movement in the joints. Support for this suggestion provides results quantifying the age influence on the elastic modulus, showing that the elastic modulus decreases from about 120 MPa at the age of 20 to about 60 MPa at the age of 80. 17
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341
TABLE 4 Comparison of Active ROM Measures (±SD) with Age and with Gender and Age Group Age (men and women)"
Gender and age Men"
WomenC
N
20-39 40-59 60-69 70-79 20-39 40-59 60-69. 70-79 20-39 40-59 60-69 70-79
15 15 15 16 15 15 15 15
Dorsiflexion
Plantarflexion
25.51 25.38 22.98 22.57
± ± ± ±
6.6 5.9 5.2 6.1
44.60 40.30 38.89 37.03
25.0 27.1 25.4 26.4 26.0 23.7 20.6 18.5
± ± ± ± ± ± ± ±
7.0 5.9 4.7 4.7 6.4 5.7 4.6 4.8
± ± ± ±
8.8 7.8 6.8 7.2
41.0±9.9 40.0 ± 6.2 36.2 ± 5.6 33.7 ± 6.9 48.2 ± 5.9 40.6 ± 9.4 41.6 ± 7.1 40.5 ± 5.9
Inversion
20.61 20.70 17.14 17.05
± ± ± ±
6.7 8.0 5.8 5.7
Eversion
14.93 13.77 12.29 11.39
19.8±6.1 21.8 ± 8.2 19.0 ± 5.5 18.6 ± 5.6 21.4 ± 7.3 19.6±7.9 15.3 ± 5.5 15.3 ± 5.5
± ± ± ±
Abduction
5.1 3.3 3.2 3.3
37.81 33.22 31.65 31.29
± ± ± ±
10.1 7.6 5.4 8.5
12.6 ± 4.0 13.3 ± 3.6 13.0 ± 3.4 11.4 ± 3.2 17.2 ± 5.2 14.2 ± 3.1 11.6±2.9 11.4 ± 3.5
35.4 32.5 30.7 29.7 40.2 33.9 32.6 33.0
± ± ± ± ± ± ± ±
9.1 6.8 4.5 8.8 10.7 8.5 6.1 8.1
Adduction
34.61 29.93 27.86 27.07
± ± ± ±
9.5 9.1 8.5 7.4
33.5±10.1 32.3 ± 6.6 30.6 ± 6.3 27.7 ± 6.6 35.8 ± 8.9 27.6 ± 10.7 25.1 ± 9.8 26.4 ± 8.5
a Plantarflexion, inversion, abduction, and adduction were significantly different with age (P < .05). Dorsiflexion and eversion had a significant gender and age interaction (P < .05). b Plantarflexion was significantly different with age (P < .05). C Dorsiflexion, plantarflexion, inversion, eversion, and adduction were significantly different with age (P < .05).
3. Articular cartilage is changing with increasing age, reducing the possible motion in a joint. Changes of articular cartilage as a function of age, such as a gradual decrease in tensile fatigue properties," have been documented. However, the relationship between these changes and actual movement are not known yet. In general, the AIROM values of the foot for the combined male and female group (Table 5) decreased between 20 and 80 years of age. The relative changes were in the same order of magnitude for all six directions (dorsiflexion, plantarflexion, inversion, eversion, adduction, and abduction; 12% to 24%). However, the findings were different for women and men in the subject sample used in this study. The gender-relateddifferences can be summarized and discussed as follows: First, the reduction of the absolute AIROM values from the youngest to the oldest group was about twice as large for women than for men. It may be speculated that this may be a result of the different amount and type of physical activity of men and women, assuming that the AIROM of the foot and physical activity are related and that men in general may do more physical activity than women during their life span. Second, women showed the lowest relative reduction as a function of age in movement directions, whereas men showed the highest reduction, and vice versa. Female AIROM reductions were significantly higher for dorsiflexion and eversion, movement components which occur more likely in physical activities but only in a limited amount in daily activities. Third, the change in the AIROM results was influenced by the initial starting values. A comparison of the AIROM values for the youngest age group showed that the AIROM was larger for women than for men for all movement directions (Table 6). However, with increas-
TABLE 5 Mean Differences in AIROM between the Youngest and the Oldest Age Groups for the Total Group as well as for the Male and Female Groups Difference (young, old) Movement
All
Men
Women (0) (%)
(0)
(%)
(0)
Dorsiflexion Plantarflexion Inversion Eversion Abduction Adduction
2.9 7.6 3.6 3.5 6.5 7.5
12 17 17 24 17 22
-1.4 7.3 1.2 1.2 5.7 5.8
-1 18 6 10 16 17
7.5 7.7 6.1 5.8 7.2 9.4
29 a 16 29 34 a 18 26
Average difference
5.3
18
3.8
11
7.3
25
(%)
Differences between results for male and female groups were determined with a multivariate analysis of variance test. a
TABLE 6 Differences in AIROM Values between Males and Females for the Youngest and the Oldest Age Groups Men and women Movement
Youngest group (0)
Oldest group (0)
Dorsiflexion Plantarflexion Inversion Eversion Abduction Adduction
-1.0 -7.1 -1.6 -4.6 -4.8 -2.3
+7.9 -6.8 +3.3 0.0 -3.3 +1.3
Average differences
-3.5
+0.4
ing age, the ranking changed. The biggest differences occurred in dorsiflexion, where the AIROM values for men became significantly larger than for women with increasing age. In general, men showed in the average a smaller AIROM than women in the young adult age,
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whereas men and women showed about the same AIROM for the high age. However, differences existed in the specific movement directions for the oldest age group. Fourth, the differences between males and females in dorsiflexion-plantarflexion suggest that functional aspects may be of importance. Male and female footwear is often different in the dorsiflexion-plantarflexion construction. The use of high heel shoes by women may shorten the Achilles tendon, hampering AIROM in dorsiflexion but aiding AIROM in plantarflexion. In support of this speculation is the fact that dorsiflexion is about 8° smaller and plantarflexion about 8° higher for women than for men for the oldest age group. The possible connection between changes in the AIROM and physical activities is speculation, and the present setup of the experiment does not allow conclusive statements in this context. Experiments analyzing the influence of physical activity on the ROM of several joints have shown that physical activity increases the ROM of the analyzed joints and movements in these joints." More experiments specifically related to the complex movement of the foot may provide the necessary missing information to answer this question. Based on the findings of this study, we speculated that: (1) changes in the AIROM of the foot depend on age and gender; (2) changes in the AIROM of the foot are different for men and women; and (3) decreases in the AIROM of the foot as a function of age may be reduced with appropriate physical activity, Discussions about the "appropriate" measurement of the AIROM for the foot with noninvasive methods will continue. The method for the determination of the AIROM of the foot used in this project has limitations as outlined in the "Methods" section. However, one of the important advantages consists in the fact that the motion quantified corresponds to a motion that may be registered during actual movement. For locomotion analysis, the lower leg and the rear foot are usually treated as one rigid body. The movement of the rear foot with respect to the lower leg is affected by the relative bone movement, as described in the "Methods" section. Consequently, the AIROM measured with the selected methodology and the actual movement of the rear foot during locomotion may show some correlation, because similar variables are quantified. Currently, it is not clear how the findings of this study relate to shoe construction. One may speculate that stability of a shoe may become more important with decreasing AIROM of the foot. However, specific future studies quantifying the loading in the internal foot structures 14 are needed to provide specific answers to this question. Furthermore, one may speculate that, in general, shoes, and especially sport shoes for young
women, should be constructed differently than (sport) shoes for young men because (1) the AIROM of the foot is larger for women than for men in this age bracket and (2) the AIROM of the foot is shifted (about 8°) toward plantarflexion for women compared with men. ACKNOWLEDGMENTS
This project has been supported by a research grant from the Canadian Fitness and Lifestyle Research Institute, the Alberta Heritage Foundation for Medical Research, and a research grant from Adidas.
REFERENCES 1. Alexander, R.McN.: Elastic Mechanisms in Animal Movement. Cambridge, Cambridge University Press, 1988. 2. Allinger, T.L.: A Method to Determine the Static Range of Motion of the Ankle Joint Complex In Vivo. Master's thesis, University of Calgary, Canada, 1990. 3. Barnett, C.H., and Napier, J.R.: The axis of rotation at the ankle joint in man. Its influence upon the form of the talus and the mobility of the fibula. Anatomy, 86:1-9,1952. 4. Close, J.R.: Some application of the functional anatomy of the ankle joint. J. Bone Joint Surg., 38(A4):761-781, 1956. 5. Engsberg, J.R.: A biomechanical analysis of the tala-calcaneal jointin vitro. J. Biomech., 20:429-442, 1987. 6. Engsberg, J.R., and Allinger, T.L.: A function of the talocalcaneal joint during running support. Foot Ankle, 11:93-96, 1990. 7. Engsberg, J.R., Grimston, S.K., and Wackwitz, J.: Predicting talo-calcaneal joint orientations from talo-calcaneal/talo-crural joint orientations. J. Orthop. Res., 6:749-757,1988. 8. Inman, V.T., and Mann, R.A.: Biomechanics of the foot and ankle. In Surgery of the Foot. St. Louis, C.V. Mosby, 1973, pp. 3-22. 9. Ker, R.F., Bennett, M.B., Bibby, S.R., Kester, R.C., and Alexander, R.McN.: The spring in the arch of the human foot. Nature, 325:147-149, 1987. 10. Luethi, S.M., Frederick, E.C., Hawes, M.R., and Nigg, B.M.: Influence of shoe construction on lower extremity kinematics and load during lateral movements in tennis. Int. J. Sports Biomech., 2:166-174,1986. 11. Lundberg, A., Goldie, I., Kalin, B., and Selvik, G.: Kinematics of the ankle/foot complex: plantarflexion and dorsiflexion. Foot Ankle, 9:194-200, 1989a. 12. Lundberg, A., Svensson, O.K., Bylund, C., Goldie, I., and Selvik, G.: Kinematics of the ankle/foot complex-part 2: pronation and supination. Foot Ankle, 9:248-253, 1989b. 13. Lundberg, A., Svensson, O.K., Bylund, C., and Selvik, G.: Kinematics of the ankle/foot complex-part 3: influence of leg rotation. Foot Ankle, 9:304-309, 1989c. 14. Morlock, M., and Nigg, B.M.: Theoretical considerations and practical results on the influence of the representation of the foot for the estimation of internal forces with models. Clin. Biomech., 6:3-13,1991. 15. Nigg, B.M.: Biomechanics of Running Shoes. Champaign, IL, Human Kinetics, 1986. 16. Nigg, B.M., Frederick, E.C., Hawes, M.R., and Luethi, S.M.: Factors influencing short term pain and injuries in tennis. Int. J. Sports Biomech., 2:156-165,1986. 17. Noyes, F.R., and Grood, E.S.: The strength of the anterior
Downloaded from fai.sagepub.com at UNIV ALABAMA LIBRARY/SERIALS on December 19, 2014
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18.
19.
20. 21.
cruciate ligament in humans and rhesus monkeys. Age related and species related changes. J. Bone Joint Surg., 58A:10741082,1976. Raab, M.S., Agre, J.C., McAdam, M., and Smith, E.L.: Light resistance and stretching exercise in elderly women: effect upon flexibility. Arch. Phys. Med. Rehabil., 69:268-272, 1988. Roass, A., and Anderson, G.B.J.: Normal range of motion of the hip, knee and ankle joints in male subjects, 30-40 years of age. Acta Orthop. Scand., 53:205-208,1982. Scott, S.H., and Winter, D.A.: Personal communication, 1991. Siegler, S., Chen, J., and Schneck, C.D.: The three-dimensional kinematics and flexibility characteristics of the human ankle and subtalar joints-part I: kinematics. J. Biomech. Eng., 110:364-
343
373,1988. 22. Stormont, D.M., Morrey, B.F., An, K., and Cass, J.R.: Stability of the loaded ankle-relation between articular restraint and primary and secondary static restraints. Am. J. Sports Med., 13:295-300,1985. 23. Weightman, B.: In vitro fatigue testing of articular cartilage. Ann. Rheum. Dis., 34(Suppl 2):108-110, 1975. 24. Weseley, M.S., Koval, R., and Kleiger, B.: Roentgen measurements of ankle flexion-extension measurement. Clin. Orthop., 65:167-174,1969. 25. Wright, D.G., Desai, S.M., and Henderson, W.H.: Action of the subtalar and ankle joint complex during the stance phase of walking. J. Bone Joint Surg., 46(A2):361-382, 1964.
Downloaded from fai.sagepub.com at UNIV ALABAMA LIBRARY/SERIALS on December 19, 2014
