G Model JSAMS-1110; No. of Pages 5
ARTICLE IN PRESS Journal of Science and Medicine in Sport xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Journal of Science and Medicine in Sport journal homepage: www.elsevier.com/locate/jsams
Original research
The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study Laura Hutchison, Rolf Scharfbillig, Hayley Uden, Chris Bishop ∗ School of Health Sciences, University of South Australia, City East Campus, Adelaide, Australia
a r t i c l e
i n f o
Article history: Received 23 December 2013 Received in revised form 17 September 2014 Accepted 7 November 2014 Available online xxx Keywords: Shoes Biomechanics Knee Orthotic devices Running
a b s t r a c t Objectives: This study aimed to determine the immediate effects of footwear and foot orthoses on transverse plane rotation of the knee joint during the stance phase of jogging gait. Design: An experimental, within subjects, repeated measures design. Methods: Three-dimensional knee kinematics were estimated in the transverse plane by surface-mounted markers as 14 asymptomatic participants ran in four randomised conditions; neutral shoe, neutral shoe with customised orthoses, neutral shoe with prefabricated orthoses, and a stability shoe. Peak internal/external rotation joint angles and ranges of motion (ROM) during loading response, midstance and propulsion were determined. Immediate subjective comfort was also recorded for each condition using a 100 mm visual analogue scale. Results: Significant main effects of condition were observed for all outcomes except transverse plane knee ROM during loading response (p < 0.05). All significant differences occurred between the stability shoe and another condition, with less knee internal rotation in the stability shoe (mean differences ranged between 1.7◦ and 6.1◦ ) (p < 0.05). The neutral shoe with prefabricated orthoses was reported as more uncomfortable than all other testing conditions. Conclusions: The stability shoe reduced peak knee internal rotation throughout stance phase of jogging more than any other condition. Importantly, it was subjectively as comfortable as the other conditions. These results identify the ability for footwear alone to induce immediate proximal kinematic effects. The use of the kinematic theory behind foot orthoses therapy is also questioned. © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
1. Introduction Injuries to the knee are the most common lower limb injury sustained during running.1 As a treatment strategy of knee injuries in clinical practice, foot orthoses are routinely used with the belief that they have a direct effect on the knee. Excessive pronation (hindfoot eversion) of the subtalar joint with associated internal rotation of the tibia relative to the femur (transverse plane knee rotation) has been postulated to be a causative factor of lower limb overuse injuries such as anterior knee pain.2 In an attempt to understand both the mechanism of injury and the orthoses in executing their effect, biomechanical modelling techniques have been used to investigate the role of altered knee biomechanics, and specifically lower leg rotation.3 Central to these investigations has been the immediate role of foot orthoses. Foot orthoses have been shown to exert their effects on the lower limb through a number
∗ Corresponding author. E-mail address: [email protected] (C. Bishop).
of pathways including alteration of joint kinematics, kinetics (i.e. joint moments), attenuation of impact forces and neuromotor control paradigms.3,4 However, the most widely used clinically is the kinematic theory, which is based on the premise that excessive pronation of the subtalar joint is reduced by the use of foot orthoses which in turn restores the joint coupling relationship between the foot and lower leg.3 To date though, the literature relating to the effect of foot orthotics on knee kinematics demonstrates small effects (i.e. 0.64,11 within session CMC = 0.96912 ) and consistent with output from models using functional methods.11 The duration of stance phase was time normalised to 101 points. Given the prior established relationship between foot eversion and transverse plane rotation of the lower leg,18 peak internal and external rotation angles were calculated, as was transverse
Table 1 Anatomical marker locations. Segment
Reference markers
Tracking markers
Pelvis
Thigh
Right anterior superior iliac spine Right posterior superior iliac spine Left anterior superior iliac spine Left posterior superior iliac spine Right greater trochanter
Right anterior superior iliac spine Right posterior superior iliac spine Left anterior superior iliac spine Left posterior superior iliac spine 4 plate mounted markers on distal 1/3 of thigh segment (right leg)
Lower leg
Right lateral femoral Epicondyle Right medial femoral Epicondyle Right lateral femoral Epicondyle
Foot–shoe complex
Right medial femoral Epicondyle Right lateral Malleolus Right medial Malleolus Right lateral Malleolus Right medial Malleolus 1st metatarsal head 5th metatarsal head
4 plate mounted markers on distal 1/3 of shank segment (right leg)
Posterior calcaneus 1st metatarsal head 2nd metatarsal head 5th metatarsal head
Please cite this article in press as: Hutchison L, et al. The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.007
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Table 2 Research variable data. Research variable
Peak knee flexion angle (◦ ) Peak knee internal rotation angle (◦ ) Peak knee external rotation angle (◦ ) Total knee rotation ROM (◦ ) Knee rotation ROM during Loading (◦ ) Knee rotation ROM during Midstance (◦ ) Knee rotation ROM during propulsion (◦ ) Shoe comfort (mm on 100 mm VAS)
Neutral shoe (NS)
NS + Custom orthotic
NS + Prefab orthotic
Stability shoe
Mean
SD
Mean
SD
Mean
SD
Mean
SD
34.2 21.9 −2.1 24.5 2.4 11.3 24.1 69.5
3.4 5.3 6.4 6.1 2.0 3.6 6.7 22.8
35.4 21.9 −2.8 23.9 2.9 11.4 23.8 62.6
2.9 5.3 8.0 6.0 1.9 4.3 6.0 20.0
34.2 22.2 −3.5 26.1 2.3 11.2 25.8 49.3
3.0 5.0 6.3 6.0 1.6 3.3 5.9 28.9
35.6 18.6 −8.2 26.4 2.8 12.8 26.0 69.4
6.3 6.1 7.6 6.5 1.8 3.0 6.9 21.3
plane range of motion (ROM) during loading response (0–15% of stance). Transverse plane ROM during midstance (15–50% of stance) and propulsion (50–100% of stance) were also extracted as the remaining functional ranges during stance phase. Data were analysed in SPSS (version 20, IBM, USA). All data were examined visually for normality (all data were normally distributed), and a general linear mixed model with post hoc sequential Bonferroni adjusted t-tests was used to determine differences between each experimental condition relative to the neutral shoe (p = 0.05). To rule out the influence of cross-talk, the peak knee flexion angle during stance was added as a covariate to the model. Paired-sample t-tests with Bonferroni corrections for multiple comparisons were computed for differences in self-reported comfort of each condition. 3. Results No significant differences in running speed occurred between testing conditions (range = 2.94–2.97 ms−1 , p > 0.05). In the model, individual trials and knee flexion had p-values greater than 0.05 which means that they are not significant predictors of rotation and can be removed from the model. Significant main effect of condition occurred for both peak internal and peak external knee rotation, and transverse plane ROM during midstance and propulsion (p < 0.05, ES range 0.41–0.87, see Table 2). The knee was significantly less internally rotated in the stability shoe condition compared to all other conditions (mean difference range = 3.2–3.5◦ , p < 0.001, ES range = 0.49–0.87, see Fig. 1). As there was no difference in total ROM, the stability shoe was more externally rotated than all condition at its peak value (mean difference range = 4.7–6.1◦ , p < 0.001, ES range = 0.67–0.87). A significant, but small, increase in transverse plane ROM also occurred in the stability shoe compared to the neutral shoe alone (mean difference = 1.6◦ , p = 0.043, ES = 0.41) and the neutral shoe with prefabricated orthoses (mean difference = 1.7◦ , p = 0.027, ES = 0.45) conditions during midstance. During propulsion, more transverse plane ROM was identified in the stability shoe condition compared to the neutral shoe with customised orthoses during propulsion (mean difference = 2.2◦ , p = 0.032, ES = 0.44). No significant main effect of condition occurred for transverse plane ROM during loading response (p > 0.05). In terms of comfort, the means ± standard deviations (SD) for each condition are provided in Table 2. Whilst no significant differences were identified between conditions (p > 0.05), the size of the effect identified between the neutral shoe + prefabricated orthotic and all other conditions were moderate (ES range = 0.52–0.74). 4. Discussion The aims of this study were to determine the immediate effect of footwear and foot orthoses on transverse plane knee kinematics during the stance phase of running. Within this study, evidence was presented to suggest the immediate use of stability footwear
Main effect
p > 0.05 p < 0.05 p < 0.05 p > 0.05 p > 0.05 p < 0.05 p < 0.05 p > 0.05
alters transverse plane knee kinematics compared to a neutral shoe. However, there were no significant differences to suggest the immediate use of prefabricated or customised foot orthoses had an effect on transverse plane knee rotation when compared to the neutral shoe condition. Few studies have previously investigated the effect of footwear on transverse plane knee kinematics during over ground running. Lilley and co-workers19 reported results in agreement with the current study, with a decrease in peak knee internal rotation angle during a motion control condition compared to a neutral shoe (p < 0.05). This agreement in results is likely due to similarity in interventions used in the current study. Other studies investigating the effect of footwear on transverse plane knee kinematics have not resulted in significant main effect of shoe.20–22 It is likely these three studies do not concur with the current study due to discrepancies in shoe type and methodologies. The analysis of knee joint kinematics in this study has been conducted to give as much relevance to clinical practice as possible, so we choose to analyse kinematics via the functional phases of gait; loading response, midstance and propulsion. However, we do accept that the results presented are specific to the type of orthoses used in this study. Analysis of the running gait cycle has revealed that peak hindfoot eversion occurs during loading response (0–15% stance). A coupling relationship has previously been shown between hindfoot eversion and transverse plane tibial internal rotation; that is as the hindfoot reaches peak eversion, the tibia should be in peak internal rotation.18 However, within the current study, peak tibial internal rotation was found to occur within the ‘propulsive’ phase of gait (in the last 50% of stance phase). This further questions the kinematic theory behind the use of foot orthoses for knee joint pathology and if it is still appropriate to be using this clinical reasoning in practice. In comparison to the paucity of literature describing the effect of athletic footwear on the knee joint kinematics, a number of studies have evaluated the effect of foot orthoses on transverse plane knee kinematics during over ground running. A systematic review by Mills and co-workers3 identified 20 comparisons between foot orthoses and a control involving tibial internal rotation during running. A meta-analysis found when participants with no injury history wore posted non-moulded orthoses, a small decrease of 1.33◦ in tibial internal rotation occurred when running.3 However, it is questionable whether such a small difference actually occurred as a result of the intervention. Where mean-differences between conditions are important data (especially pilot data given it is often used to power future research), transverse plane kinematics are highly variable and affected by methods in their calculation. Therefore, considering the relationship between kinematics and patient-reported outcome measures is likely to provide more information to the true effect of an intervention on a participant and/or population. In the current study, no significant differences in transverse plane knee joint rotation were detected between either orthoses condition and the neutral shoe (p > 0.05). This indicates that the addition of these devices in this study did not provide
Please cite this article in press as: Hutchison L, et al. The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.007
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Fig. 1. The transverse plane knee joint angle normalised to 100% of stance.
additional immediate biomechanical effect on the knee (i.e. change the coupling ratio) over and above that identified when wearing the neutral shoe. However, it is important to understand that this study was designed to investigate immediate effects, and future research should attempt to capture prolonged data of the effect of orthoses after a prolonged acclimatisation period. This may well provide different results than seen in this study. Although statistically significant differences were noted in previous studies regarding foot orthoses and comfort, no differences were identified in this study (p > 0.05). This is likely because of the small sample size and exploratory nature of this work. In saying this, moderate effects were noticed between the prefabricated orthotic condition and all other condition, and it is important to determine whether these differences are clinically relevant. The minimal clinically important difference is defined as the smallest difference in a score that patients perceive to be beneficial.23 Mills et al.14 determined a clinically important change in comfort as 10.2 mm on the 100 mm VAS. Despite the lack of statistical significance (which is likely a result of the study being underpowered to identify a difference), it can therefore be concluded that the neutral shoe with prefabricated orthoses condition was clinically more uncomfortable than each of the other conditions. Limitations within the current study are acknowledged. Principally, we acknowledge the variability of calculating transverse plane kinematics. Small differences were noted in this study that could possibly be introduced by errors including STA, cross-talk and marker placement. It is important that in future studies, kinematic data is considered in light of its clinical relevance (i.e. a small kinematic change could be very meaningful if a large reduction was associated with the change). The sample size was small (14 participants) and potentially underpowered, yet this was hypothesis generating research (i.e. a pilot study). We acknowledge the potential differences between males and females in terms of lower limb biomechanics and injury risk, and differentiating population cohorts based on age and sex is certainly warranted in the future. In relation to the orthoses used, it can be debated whether the customised orthoses provided to participants (based on a standardised prescription) were indicative of those used in clinical practice. As
there is no accepted approach to foot orthotic prescription in the literature and that the individual response to orthoses is widely variable, we wanted to control for as much variability as possible by using a standardised prescription. In saying this, it is likely that in the future (and with the creation of appropriate consensus statements), the understanding of orthoses effects will benefit from customised prescriptions for each participant. It could be argued that the running speed in this study was quite slow, yet it was of the belief that such a speed (3 ms−1 ± 5%) is likely representative of the average recreational runner (approximately 10.5 km/h). Further, it must be again emphasised that immediate effects were reported, and prolonged exposure to the experimental conditions may produce markedly different results. Finally, the question of whether the magnitude of change seen between conditions is clinically relevant was not intended to be and cannot be directly answered by this study. This study was designed to explore potential kinematic effects. In saying this, given this was both a pilot study and recruited asymptomatic participants, we again emphasise the need to associate kinematic data with patient reported outcome measures to identify whether any changes in transverse plane rotations are actually clinically meaningful. Thus, despite our data providing preliminary evidence to the potential effect of footwear and orthoses, it should be used to power future research designed to investigate populations experiencing pain and/or discomfort resulting from transverse plane deformity (e.g. anterior knee pain).
5. Conclusion This study looked to describe the immediate effect of footwear and foot orthoses on the knee joint during stance phase of running. The results indicated that a stability shoe alters knee joint kinematics when compared to a neutral shoe and both customised and prefabricated foot orthoses, with less peak internal rotation and greater peak external rotation observed. Using the peak knee flexion angle during stance as a covariate enabled us to determine that the differences in transverse plane kinematics were true effects of condition, and not a result of cross-talk. This identifies
Please cite this article in press as: Hutchison L, et al. The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.007
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the ability of footwear alone to produce proximal kinematic effects. Importantly, the stability shoe was clinically as comfortable as the other testing conditions. The results of the current study also found there is no evidence to suggest the immediate use of prefabricated or customised orthoses changes transverse plane knee joint kinematics during the stance phase of running over and above that seen when wearing neutral shoes. This questions the use of the kinematic theory behind the basis of foot orthoses therapy for knee joint pathology. However, due to observed clinical effects of foot orthoses on the knee, it is possible that they affect the knee in other ways than altering joint kinematics. Given the positive clinical benefits of foot orthoses in the literature, appropriately powered research needs to explore the preliminary relationships identified in this study, as well as other potential mechanisms of effect of both footwear and foot orthoses. This research could also be targeted towards pathological populations to determine if similar trends are apparent. 6. Practical implications 1) Footwear alone has a direct effect on the knee supported by the fact that the stability shoe reduced internal knee joint rotation more than either orthoses condition. 2) Prefabricated orthoses are clinically more uncomfortable than customised orthoses, and neutral and stability shoes alone. 3) The assumed kinematic basis behind foot orthotic success must be re-visited. Conflict of interests None. Acknowledgements ASICS Oceania, Vasyli Medical. References 1. Taunton J, Ryan M, Clement D et al. A retrospective case-control analysis of 2002 running injuries. Br J Sports Med 2002; 44:11. 2. Hadley A, Griffiths S, Griffiths L et al. Antipronation taping and temporary orthoses. J Am Podiatr Med Assoc 1999; 89(3):6.
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3. Mills K, Blanch P, Chapman A et al. Foot orthoses and gait: a systematic review and meta-analysis of literature pertaining to potential mechanisms. Br J Sports Med 2010; 44:11. 4. Mündermann A, Nigg BM, Humble RN et al. Foot orthotics affect lower extremity kinematics and kinetics during running. Clin Biomech 2003; 18(3): 254–262. 5. Cheung RT, Wong MY, Ng GY. Effects of motion control footwear on running: a systematic review. J Sports Sci 2011; 29(12):1311–1319. 6. Redmond A. The foot posture index: user guide and manual, 2005. Available at: http://www.leeds.ac.uk/medicine/FASTER/fpi.htm 7. WMA. World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects, 2008. Available at: http://www.wma. net/en/30publications/10policies/b3/17c.pdf 8. Dallal G. Welcome to randomization.com, 2008. Available at: www. randomization.com 9. Bishop C, Paul G, Thewlis D. The reliability, accuracy and minimal detectable difference of a multi-segment kinematic model of the foot–shoe complex. Gait Posture 2012. 10. Thewlis D, Richards J, Bower J. Discrepancies in knee joint moments using common anatomical frames defined by different palpable landmarks. J Appl Biomech 2008; 24(2):185–190. 11. Besier TF, Sturnieks DL, Alderson JA, Lloyd DG. Repeatability of gait data using a functional hip joint centre and a mean helical knee axis. J Biomech 2003; 36(8):1159–1168. 12. Collins TD, Ghoussayni SN, Ewins DJ, Kent JA. A six degrees-of-freedom marker set for gait analysis: repeatability and comparison with a modified Helen Hayes set. Gait Posture 2009; 30(2):173–180. 13. Van Sint Jan S. Color atlas of skeletal landmark definitions: guidelines for reproducible manual and virtual palpations, Elsevier, 2007. 14. Mills K, Blanch P, Vicenzino B. Identifying clinically meaningful tools for measuring comfort perception of footwear. Med Sci Sports Exerc 2010; 42(10):1966–1971. 15. Winter D. Biomechanics and motor control of human movement, John Wiley & Sons, Inc., 2005. 16. Cappozzo A, Catani F, Della Croce U et al. Position and orientation in space of bones during movement: anatomical frame definition and determination. Clin Biomech 1995; 10(4):171–178. 17. Lu T-W, O’Äôconnor J. Bone position estimation from skin marker co-ordinates using global optimisation with joint constraints. J Biomech 1999; 32(2): 129–134. 18. DeLeo AT, Dierks TA, Ferber R et al. Lower extremity joint coupling during running: a current update. Clin Biomech 2004; 19(10):983–991. 19. Lilley K, Stiles V, Dixon S. The influence of motion control shoes on the running gait of mature and young females. Gait Posture 2013; 37:5. 20. Butler RJ, Davis IS, Hamill J. Interaction of arch type and footwear on running mechanics. Am J Sports Med 2006; 34(12):1998–2005. 21. MacLean CL, Davis IS, Hamill J. Influence of running shoe midsole composition and custom foot orthotic intervention on lower extremity dynamics during running. J Appl Biomech 2009; 25(1):54. 22. Lee Y, Kim YK, Kim YH. Kinematic and kinetic analyses of novice running in dress shoes and running shoes. Acta Bioeng Biomech 2011; 13(3):55–61. 23. Mills K, Blanch P, Vicenzino B. Influence of contouring and hardness of foot orthoses on ratings of perceived comfort. Med Sci Sports Exerc 2011; 43(8):1507–1512.
Please cite this article in press as: Hutchison L, et al. The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.007
ARTICLE IN PRESS Journal of Science and Medicine in Sport xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Journal of Science and Medicine in Sport journal homepage: www.elsevier.com/locate/jsams
Original research
The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study Laura Hutchison, Rolf Scharfbillig, Hayley Uden, Chris Bishop ∗ School of Health Sciences, University of South Australia, City East Campus, Adelaide, Australia
a r t i c l e
i n f o
Article history: Received 23 December 2013 Received in revised form 17 September 2014 Accepted 7 November 2014 Available online xxx Keywords: Shoes Biomechanics Knee Orthotic devices Running
a b s t r a c t Objectives: This study aimed to determine the immediate effects of footwear and foot orthoses on transverse plane rotation of the knee joint during the stance phase of jogging gait. Design: An experimental, within subjects, repeated measures design. Methods: Three-dimensional knee kinematics were estimated in the transverse plane by surface-mounted markers as 14 asymptomatic participants ran in four randomised conditions; neutral shoe, neutral shoe with customised orthoses, neutral shoe with prefabricated orthoses, and a stability shoe. Peak internal/external rotation joint angles and ranges of motion (ROM) during loading response, midstance and propulsion were determined. Immediate subjective comfort was also recorded for each condition using a 100 mm visual analogue scale. Results: Significant main effects of condition were observed for all outcomes except transverse plane knee ROM during loading response (p < 0.05). All significant differences occurred between the stability shoe and another condition, with less knee internal rotation in the stability shoe (mean differences ranged between 1.7◦ and 6.1◦ ) (p < 0.05). The neutral shoe with prefabricated orthoses was reported as more uncomfortable than all other testing conditions. Conclusions: The stability shoe reduced peak knee internal rotation throughout stance phase of jogging more than any other condition. Importantly, it was subjectively as comfortable as the other conditions. These results identify the ability for footwear alone to induce immediate proximal kinematic effects. The use of the kinematic theory behind foot orthoses therapy is also questioned. © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
1. Introduction Injuries to the knee are the most common lower limb injury sustained during running.1 As a treatment strategy of knee injuries in clinical practice, foot orthoses are routinely used with the belief that they have a direct effect on the knee. Excessive pronation (hindfoot eversion) of the subtalar joint with associated internal rotation of the tibia relative to the femur (transverse plane knee rotation) has been postulated to be a causative factor of lower limb overuse injuries such as anterior knee pain.2 In an attempt to understand both the mechanism of injury and the orthoses in executing their effect, biomechanical modelling techniques have been used to investigate the role of altered knee biomechanics, and specifically lower leg rotation.3 Central to these investigations has been the immediate role of foot orthoses. Foot orthoses have been shown to exert their effects on the lower limb through a number
∗ Corresponding author. E-mail address: [email protected] (C. Bishop).
of pathways including alteration of joint kinematics, kinetics (i.e. joint moments), attenuation of impact forces and neuromotor control paradigms.3,4 However, the most widely used clinically is the kinematic theory, which is based on the premise that excessive pronation of the subtalar joint is reduced by the use of foot orthoses which in turn restores the joint coupling relationship between the foot and lower leg.3 To date though, the literature relating to the effect of foot orthotics on knee kinematics demonstrates small effects (i.e. 0.64,11 within session CMC = 0.96912 ) and consistent with output from models using functional methods.11 The duration of stance phase was time normalised to 101 points. Given the prior established relationship between foot eversion and transverse plane rotation of the lower leg,18 peak internal and external rotation angles were calculated, as was transverse
Table 1 Anatomical marker locations. Segment
Reference markers
Tracking markers
Pelvis
Thigh
Right anterior superior iliac spine Right posterior superior iliac spine Left anterior superior iliac spine Left posterior superior iliac spine Right greater trochanter
Right anterior superior iliac spine Right posterior superior iliac spine Left anterior superior iliac spine Left posterior superior iliac spine 4 plate mounted markers on distal 1/3 of thigh segment (right leg)
Lower leg
Right lateral femoral Epicondyle Right medial femoral Epicondyle Right lateral femoral Epicondyle
Foot–shoe complex
Right medial femoral Epicondyle Right lateral Malleolus Right medial Malleolus Right lateral Malleolus Right medial Malleolus 1st metatarsal head 5th metatarsal head
4 plate mounted markers on distal 1/3 of shank segment (right leg)
Posterior calcaneus 1st metatarsal head 2nd metatarsal head 5th metatarsal head
Please cite this article in press as: Hutchison L, et al. The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.007
G Model JSAMS-1110; No. of Pages 5
ARTICLE IN PRESS L. Hutchison et al. / Journal of Science and Medicine in Sport xxx (2014) xxx–xxx
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Table 2 Research variable data. Research variable
Peak knee flexion angle (◦ ) Peak knee internal rotation angle (◦ ) Peak knee external rotation angle (◦ ) Total knee rotation ROM (◦ ) Knee rotation ROM during Loading (◦ ) Knee rotation ROM during Midstance (◦ ) Knee rotation ROM during propulsion (◦ ) Shoe comfort (mm on 100 mm VAS)
Neutral shoe (NS)
NS + Custom orthotic
NS + Prefab orthotic
Stability shoe
Mean
SD
Mean
SD
Mean
SD
Mean
SD
34.2 21.9 −2.1 24.5 2.4 11.3 24.1 69.5
3.4 5.3 6.4 6.1 2.0 3.6 6.7 22.8
35.4 21.9 −2.8 23.9 2.9 11.4 23.8 62.6
2.9 5.3 8.0 6.0 1.9 4.3 6.0 20.0
34.2 22.2 −3.5 26.1 2.3 11.2 25.8 49.3
3.0 5.0 6.3 6.0 1.6 3.3 5.9 28.9
35.6 18.6 −8.2 26.4 2.8 12.8 26.0 69.4
6.3 6.1 7.6 6.5 1.8 3.0 6.9 21.3
plane range of motion (ROM) during loading response (0–15% of stance). Transverse plane ROM during midstance (15–50% of stance) and propulsion (50–100% of stance) were also extracted as the remaining functional ranges during stance phase. Data were analysed in SPSS (version 20, IBM, USA). All data were examined visually for normality (all data were normally distributed), and a general linear mixed model with post hoc sequential Bonferroni adjusted t-tests was used to determine differences between each experimental condition relative to the neutral shoe (p = 0.05). To rule out the influence of cross-talk, the peak knee flexion angle during stance was added as a covariate to the model. Paired-sample t-tests with Bonferroni corrections for multiple comparisons were computed for differences in self-reported comfort of each condition. 3. Results No significant differences in running speed occurred between testing conditions (range = 2.94–2.97 ms−1 , p > 0.05). In the model, individual trials and knee flexion had p-values greater than 0.05 which means that they are not significant predictors of rotation and can be removed from the model. Significant main effect of condition occurred for both peak internal and peak external knee rotation, and transverse plane ROM during midstance and propulsion (p < 0.05, ES range 0.41–0.87, see Table 2). The knee was significantly less internally rotated in the stability shoe condition compared to all other conditions (mean difference range = 3.2–3.5◦ , p < 0.001, ES range = 0.49–0.87, see Fig. 1). As there was no difference in total ROM, the stability shoe was more externally rotated than all condition at its peak value (mean difference range = 4.7–6.1◦ , p < 0.001, ES range = 0.67–0.87). A significant, but small, increase in transverse plane ROM also occurred in the stability shoe compared to the neutral shoe alone (mean difference = 1.6◦ , p = 0.043, ES = 0.41) and the neutral shoe with prefabricated orthoses (mean difference = 1.7◦ , p = 0.027, ES = 0.45) conditions during midstance. During propulsion, more transverse plane ROM was identified in the stability shoe condition compared to the neutral shoe with customised orthoses during propulsion (mean difference = 2.2◦ , p = 0.032, ES = 0.44). No significant main effect of condition occurred for transverse plane ROM during loading response (p > 0.05). In terms of comfort, the means ± standard deviations (SD) for each condition are provided in Table 2. Whilst no significant differences were identified between conditions (p > 0.05), the size of the effect identified between the neutral shoe + prefabricated orthotic and all other conditions were moderate (ES range = 0.52–0.74). 4. Discussion The aims of this study were to determine the immediate effect of footwear and foot orthoses on transverse plane knee kinematics during the stance phase of running. Within this study, evidence was presented to suggest the immediate use of stability footwear
Main effect
p > 0.05 p < 0.05 p < 0.05 p > 0.05 p > 0.05 p < 0.05 p < 0.05 p > 0.05
alters transverse plane knee kinematics compared to a neutral shoe. However, there were no significant differences to suggest the immediate use of prefabricated or customised foot orthoses had an effect on transverse plane knee rotation when compared to the neutral shoe condition. Few studies have previously investigated the effect of footwear on transverse plane knee kinematics during over ground running. Lilley and co-workers19 reported results in agreement with the current study, with a decrease in peak knee internal rotation angle during a motion control condition compared to a neutral shoe (p < 0.05). This agreement in results is likely due to similarity in interventions used in the current study. Other studies investigating the effect of footwear on transverse plane knee kinematics have not resulted in significant main effect of shoe.20–22 It is likely these three studies do not concur with the current study due to discrepancies in shoe type and methodologies. The analysis of knee joint kinematics in this study has been conducted to give as much relevance to clinical practice as possible, so we choose to analyse kinematics via the functional phases of gait; loading response, midstance and propulsion. However, we do accept that the results presented are specific to the type of orthoses used in this study. Analysis of the running gait cycle has revealed that peak hindfoot eversion occurs during loading response (0–15% stance). A coupling relationship has previously been shown between hindfoot eversion and transverse plane tibial internal rotation; that is as the hindfoot reaches peak eversion, the tibia should be in peak internal rotation.18 However, within the current study, peak tibial internal rotation was found to occur within the ‘propulsive’ phase of gait (in the last 50% of stance phase). This further questions the kinematic theory behind the use of foot orthoses for knee joint pathology and if it is still appropriate to be using this clinical reasoning in practice. In comparison to the paucity of literature describing the effect of athletic footwear on the knee joint kinematics, a number of studies have evaluated the effect of foot orthoses on transverse plane knee kinematics during over ground running. A systematic review by Mills and co-workers3 identified 20 comparisons between foot orthoses and a control involving tibial internal rotation during running. A meta-analysis found when participants with no injury history wore posted non-moulded orthoses, a small decrease of 1.33◦ in tibial internal rotation occurred when running.3 However, it is questionable whether such a small difference actually occurred as a result of the intervention. Where mean-differences between conditions are important data (especially pilot data given it is often used to power future research), transverse plane kinematics are highly variable and affected by methods in their calculation. Therefore, considering the relationship between kinematics and patient-reported outcome measures is likely to provide more information to the true effect of an intervention on a participant and/or population. In the current study, no significant differences in transverse plane knee joint rotation were detected between either orthoses condition and the neutral shoe (p > 0.05). This indicates that the addition of these devices in this study did not provide
Please cite this article in press as: Hutchison L, et al. The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.007
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Fig. 1. The transverse plane knee joint angle normalised to 100% of stance.
additional immediate biomechanical effect on the knee (i.e. change the coupling ratio) over and above that identified when wearing the neutral shoe. However, it is important to understand that this study was designed to investigate immediate effects, and future research should attempt to capture prolonged data of the effect of orthoses after a prolonged acclimatisation period. This may well provide different results than seen in this study. Although statistically significant differences were noted in previous studies regarding foot orthoses and comfort, no differences were identified in this study (p > 0.05). This is likely because of the small sample size and exploratory nature of this work. In saying this, moderate effects were noticed between the prefabricated orthotic condition and all other condition, and it is important to determine whether these differences are clinically relevant. The minimal clinically important difference is defined as the smallest difference in a score that patients perceive to be beneficial.23 Mills et al.14 determined a clinically important change in comfort as 10.2 mm on the 100 mm VAS. Despite the lack of statistical significance (which is likely a result of the study being underpowered to identify a difference), it can therefore be concluded that the neutral shoe with prefabricated orthoses condition was clinically more uncomfortable than each of the other conditions. Limitations within the current study are acknowledged. Principally, we acknowledge the variability of calculating transverse plane kinematics. Small differences were noted in this study that could possibly be introduced by errors including STA, cross-talk and marker placement. It is important that in future studies, kinematic data is considered in light of its clinical relevance (i.e. a small kinematic change could be very meaningful if a large reduction was associated with the change). The sample size was small (14 participants) and potentially underpowered, yet this was hypothesis generating research (i.e. a pilot study). We acknowledge the potential differences between males and females in terms of lower limb biomechanics and injury risk, and differentiating population cohorts based on age and sex is certainly warranted in the future. In relation to the orthoses used, it can be debated whether the customised orthoses provided to participants (based on a standardised prescription) were indicative of those used in clinical practice. As
there is no accepted approach to foot orthotic prescription in the literature and that the individual response to orthoses is widely variable, we wanted to control for as much variability as possible by using a standardised prescription. In saying this, it is likely that in the future (and with the creation of appropriate consensus statements), the understanding of orthoses effects will benefit from customised prescriptions for each participant. It could be argued that the running speed in this study was quite slow, yet it was of the belief that such a speed (3 ms−1 ± 5%) is likely representative of the average recreational runner (approximately 10.5 km/h). Further, it must be again emphasised that immediate effects were reported, and prolonged exposure to the experimental conditions may produce markedly different results. Finally, the question of whether the magnitude of change seen between conditions is clinically relevant was not intended to be and cannot be directly answered by this study. This study was designed to explore potential kinematic effects. In saying this, given this was both a pilot study and recruited asymptomatic participants, we again emphasise the need to associate kinematic data with patient reported outcome measures to identify whether any changes in transverse plane rotations are actually clinically meaningful. Thus, despite our data providing preliminary evidence to the potential effect of footwear and orthoses, it should be used to power future research designed to investigate populations experiencing pain and/or discomfort resulting from transverse plane deformity (e.g. anterior knee pain).
5. Conclusion This study looked to describe the immediate effect of footwear and foot orthoses on the knee joint during stance phase of running. The results indicated that a stability shoe alters knee joint kinematics when compared to a neutral shoe and both customised and prefabricated foot orthoses, with less peak internal rotation and greater peak external rotation observed. Using the peak knee flexion angle during stance as a covariate enabled us to determine that the differences in transverse plane kinematics were true effects of condition, and not a result of cross-talk. This identifies
Please cite this article in press as: Hutchison L, et al. The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.007
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the ability of footwear alone to produce proximal kinematic effects. Importantly, the stability shoe was clinically as comfortable as the other testing conditions. The results of the current study also found there is no evidence to suggest the immediate use of prefabricated or customised orthoses changes transverse plane knee joint kinematics during the stance phase of running over and above that seen when wearing neutral shoes. This questions the use of the kinematic theory behind the basis of foot orthoses therapy for knee joint pathology. However, due to observed clinical effects of foot orthoses on the knee, it is possible that they affect the knee in other ways than altering joint kinematics. Given the positive clinical benefits of foot orthoses in the literature, appropriately powered research needs to explore the preliminary relationships identified in this study, as well as other potential mechanisms of effect of both footwear and foot orthoses. This research could also be targeted towards pathological populations to determine if similar trends are apparent. 6. Practical implications 1) Footwear alone has a direct effect on the knee supported by the fact that the stability shoe reduced internal knee joint rotation more than either orthoses condition. 2) Prefabricated orthoses are clinically more uncomfortable than customised orthoses, and neutral and stability shoes alone. 3) The assumed kinematic basis behind foot orthotic success must be re-visited. Conflict of interests None. Acknowledgements ASICS Oceania, Vasyli Medical. References 1. Taunton J, Ryan M, Clement D et al. A retrospective case-control analysis of 2002 running injuries. Br J Sports Med 2002; 44:11. 2. Hadley A, Griffiths S, Griffiths L et al. Antipronation taping and temporary orthoses. J Am Podiatr Med Assoc 1999; 89(3):6.
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3. Mills K, Blanch P, Chapman A et al. Foot orthoses and gait: a systematic review and meta-analysis of literature pertaining to potential mechanisms. Br J Sports Med 2010; 44:11. 4. Mündermann A, Nigg BM, Humble RN et al. Foot orthotics affect lower extremity kinematics and kinetics during running. Clin Biomech 2003; 18(3): 254–262. 5. Cheung RT, Wong MY, Ng GY. Effects of motion control footwear on running: a systematic review. J Sports Sci 2011; 29(12):1311–1319. 6. Redmond A. The foot posture index: user guide and manual, 2005. Available at: http://www.leeds.ac.uk/medicine/FASTER/fpi.htm 7. WMA. World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects, 2008. Available at: http://www.wma. net/en/30publications/10policies/b3/17c.pdf 8. Dallal G. Welcome to randomization.com, 2008. Available at: www. randomization.com 9. Bishop C, Paul G, Thewlis D. The reliability, accuracy and minimal detectable difference of a multi-segment kinematic model of the foot–shoe complex. Gait Posture 2012. 10. Thewlis D, Richards J, Bower J. Discrepancies in knee joint moments using common anatomical frames defined by different palpable landmarks. J Appl Biomech 2008; 24(2):185–190. 11. Besier TF, Sturnieks DL, Alderson JA, Lloyd DG. Repeatability of gait data using a functional hip joint centre and a mean helical knee axis. J Biomech 2003; 36(8):1159–1168. 12. Collins TD, Ghoussayni SN, Ewins DJ, Kent JA. A six degrees-of-freedom marker set for gait analysis: repeatability and comparison with a modified Helen Hayes set. Gait Posture 2009; 30(2):173–180. 13. Van Sint Jan S. Color atlas of skeletal landmark definitions: guidelines for reproducible manual and virtual palpations, Elsevier, 2007. 14. Mills K, Blanch P, Vicenzino B. Identifying clinically meaningful tools for measuring comfort perception of footwear. Med Sci Sports Exerc 2010; 42(10):1966–1971. 15. Winter D. Biomechanics and motor control of human movement, John Wiley & Sons, Inc., 2005. 16. Cappozzo A, Catani F, Della Croce U et al. Position and orientation in space of bones during movement: anatomical frame definition and determination. Clin Biomech 1995; 10(4):171–178. 17. Lu T-W, O’Äôconnor J. Bone position estimation from skin marker co-ordinates using global optimisation with joint constraints. J Biomech 1999; 32(2): 129–134. 18. DeLeo AT, Dierks TA, Ferber R et al. Lower extremity joint coupling during running: a current update. Clin Biomech 2004; 19(10):983–991. 19. Lilley K, Stiles V, Dixon S. The influence of motion control shoes on the running gait of mature and young females. Gait Posture 2013; 37:5. 20. Butler RJ, Davis IS, Hamill J. Interaction of arch type and footwear on running mechanics. Am J Sports Med 2006; 34(12):1998–2005. 21. MacLean CL, Davis IS, Hamill J. Influence of running shoe midsole composition and custom foot orthotic intervention on lower extremity dynamics during running. J Appl Biomech 2009; 25(1):54. 22. Lee Y, Kim YK, Kim YH. Kinematic and kinetic analyses of novice running in dress shoes and running shoes. Acta Bioeng Biomech 2011; 13(3):55–61. 23. Mills K, Blanch P, Vicenzino B. Influence of contouring and hardness of foot orthoses on ratings of perceived comfort. Med Sci Sports Exerc 2011; 43(8):1507–1512.
Please cite this article in press as: Hutchison L, et al. The effect of footwear and foot orthoses on transverse plane knee motion during running – A pilot study. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.007
