Gait & Posture 41 (2015) 323–325
Contents lists available at ScienceDirect
Gait & Posture journal homepage: www.elsevier.com/locate/gaitpost
Short Communication
The effects of specific athletic training on path selection while running Amy L. Hackney a, Allison Zakoor b, Michael E. Cinelli b,* a b
Department of Kinesiology, University of Waterloo, ON, Canada Department of Kinesiology and Physical Education, Wilfrid Laurier University, ON, Canada
A R T I C L E I N F O
A B S T R A C T
Article history: Received 27 February 2014 Received in revised form 15 September 2014 Accepted 20 September 2014
Apertures that are smaller than 1.3 times the shoulder width (SW) require that individuals make an adjustment to their normal walking behavior [6]. When given a choice, individuals will choose to avoid apertures smaller than this ratio, rather than rotate their shoulders and walk through [7]. Research has yet to determine whether this choice in path selection can be influenced by the speed at which one approaches the aperture or by experience/training. Therefore, the current study investigated whether approach speed and/or specific athletic training influences the choice in path selection. Specificallytrained athletes (n = 6) and non-trained (n = 6) young adults ran toward a visible goal placed at the end of the path and avoided an aperture (created by two poles) placed along the midline of the path. The separation between the poles ranged between 0.6 and 1.8 times each participant’s SW, in increments of 0.2. Participants were permitted to either run through or around the aperture to get to the end goal. Results demonstrated that regardless of training experience, participants ran around apertures smaller than 1.4 the SW and ran through apertures larger than this ratio. Increased approach speed (i.e., running) therefore appears to elicit similar aperture crossing behaviors as walking [2,3,6,7]. Additionally, when faced with the choice to run around or to run through apertures, individuals who are specificallytraining to run through small spaces chose similar paths as individuals who are not trained to do so. Therefore, specific training does not appear to influence voluntary path selection. ß 2014 Elsevier B.V. All rights reserved.
Keywords: Aperture crossing Path selection Action-scaled Athletic training
1. Introduction Passing through small spaces requires individuals to accurately perceive the size of the aperture relative to their body size and consider their action capabilities, including restraints on movement ability (sitting in a wheelchair) [1], movement variability [2,3] and approach speed. During locomotion, individuals must be aware of such constraints and adapt their movements accordingly. Research has suggested that experience can also influence aperture crossing performance. American football players initiate shoulder rotations closer to the aperture and produce smaller rotations compared to non-trained individuals when running through apertures but no differences exist when walking [4]. Since offensive players are trained to pass through the small spaces between the opponent’s defense while running, they likely have established a heightened awareness of body size. Furthermore, these athletes are likely more attuned to their action capabilities of passing through gaps due to practicing through spaces they may
* Corresponding author. Tel.: +1 519 884 0710x4217; fax: +1 519 747 4594. E-mail addresses: [email protected], [email protected] (M.E. Cinelli). http://dx.doi.org/10.1016/j.gaitpost.2014.09.018 0966-6362/ß 2014 Elsevier B.V. All rights reserved.
otherwise choose not to pass through. Therefore, when forced to pass through an aperture [4], performance can be influenced by experience/training however the question remains as to whether specific-training influences the voluntary choice to pass through apertures. The objective of this study was to determine whether individuals who have received specific-training choose to voluntarily pass through smaller apertures than their non-trained counterparts. Recent work demonstrates that when given the choice, nontrained individuals voluntarily chose to walk around obstacles too small for straight passage rather than pass through and rotate the shoulders [5]. The aperture width to SW ratio (A/S) that separated straight walking and avoidance situations was similar to the ratio that elicited a rotation during confined aperture crossing (1.3 SW) [5,6]. Therefore, it was hypothesized that all individuals in the current study would chose to run around apertures too small for straight passage however, specifically-trained participants would run through smaller relative spaces compared to the non-trained controls (athletes will have smaller critical points). Since research [4] demonstrated that football players only performed differently than non-football players when running, the second objective was to extend previous findings by identifying the CP which was not
A.L. Hackney et al. / Gait & Posture 41 (2015) 323–325
324
13m 5m
Aperture Width
Goal
Shoulder Width
Path option 1
Path option 2
Fig. 1. Birds-eye view of the experimental set-up with possible routes.
reported previously [5,7] and determine the influence of an increased approach speed on voluntary path selection.
measures ANOVAs were conducted to determine whether approach speed and/or onset of deviations differed between groups and/or aperture width.
2. Methods Specifically-trained offensive football players (n = 6 males) and non-trained participants (n = 6 (4 males)) provided informed consent. Participants were 20–23 years of age and had no physical/ neurological disability affecting the ability to walk/run and had not suffered a concussion within the last 3 years. Participants were instructed to run at their maximum speed along a 13 m pathway toward a goal and avoid two vertical poles placed halfway along the path (Fig. 1). Participants were given the option to run through or around the aperture but were told not to hit the poles. The width between the obstacles ranged from 0.6 to 1.8 each participant’s SW in increments of 0.2. Each aperture width was presented four times in randomized order for a total of 28 trials. Kinematic data was measured using the OptoTrak camera system (Northern Digital Inc., Waterloo) at a sampling frequency of 60 Hz with infrared light-emitting diodes (IREDs) placed on the head and the shoulders. The SW of each participant was measured to the nearest centimeter using a measure tape.
3. Results Both the frequency of path deviations and the M–L COM position at TOC decreased as the size of the aperture width increased (F(6,60) = 7.21, p < 0.05 and F(6,60) = 13.17, p < 0.01, respectively) however no effect of group was identified for frequency of path deviation (Fig. 2a) or M–L COM at TOC (Fig. 2b). Post hoc analysis determined that aperture widths 0.6–1.2 were different from straight walking (p < 0.05) for both groups for both the frequency of path deviations and the M–L COM position at TOC. Aperture widths 1.4–1.8 were not different from the straight walking values, suggesting that the CP for non-trained and trained athletes was
2.1. Data/statistical analysis Path selection was determined by the medial–lateral (M–L) position of the center of mass (COM) at the time of crossing (TOC) the obstacles. M–L COM values close to 0 cm represented straight walking trial whereas values larger than half of the absolute aperture widths were trials where the participant deviated around the obstacles. A frequency count of the total number of deviation trials at each width was calculated for both groups and an arcsin transformation converted the frequencies into parametric data. A 7(aperture width) 2(group) repeated measures ANOVA was conducted to identify whether the frequency of path deviations changed as a function of aperture width and/or group. The smallest width not significantly different from zero was considered the critical point (CP) for each group. To confirm the CP, the M–L COM position at the TOC was run through a 7(aperture width) 2(group) repeated measures ANOVA. The onset of path deviations was identified as the distance from the obstacles in which the M–L COM fell outside two standard deviations from the average straight running trials. Repeated
Fig. 2. (a) M–L COM position and (b) proportion of deviation trials at each aperture width for both the trained and non-trained groups.
A.L. Hackney et al. / Gait & Posture 41 (2015) 323–325 Table 1 Averages and standard deviations for all dependent variables.
325
1.4. The proportion explained by ‘Group’ is 0.103 and thus is not responsible for a high percentage of the variance of the scores. Onset of path deviation was not different between groups or aperture width. Additionally, approach speed did not differ between groups, although specificallytrained athletes showed a trend of running faster than their non-trained counterparts. Trained-athletes and non-athletes had similar SW. Table 1 displays all averages and standard deviations.
specifically-trained athletes would have smaller thresholds than non-trained participants and deviate closer to the aperture. It is possible that a lack of difference between groups was a result of the task itself. American football players are trained to forcefully fit through small spaces while running, but also choose the largest gap in close proximity to fit through. Previous work [4] required participants to pass through an aperture and measured the onset and necessary magnitude of rotation. The current study allowed participants to self-select the path and measured their actions. It is also possible that the null finding was due to not wearing shoulder pads. Trained athletes practice fitting through tight gaps at high speeds and do so with shoulder pads and therefore future work should consider such an effect. It appears that the effects of training previously observed during forced apertures crossings is not transferable to tasks where individuals are free to choose their path.
4. Discussion
Conflict of interest
Variable of interest
Specifically trained
Non-trained
Frequency of path deviation M-L COM position at TOC (m) Critical point Onset of path deviation (m) Approach speed (m/s) Shoulder width (cm)
0.71 (71%) 0.06 0.35 0.11 1.40 0.15 2.03 0.81 4.94 0.88) 52.8 3.2
0.68 (68%) 0.17 0.26 0.18 1.38 0.13 2.12 0.46 4.66 0.96 49.7 6.7
When presented with an aperture too small to pass through without a rotation, all participants ran around the obstacles. This is not surprising since research has demonstrated that individuals prefer to walk around obstacles that are too small for straight passage [7]. Additionally, all participants circumvented apertures smaller than 1.4 SW and ran through apertures larger than this ratio. This CP is similar to that observed when forced to walk through apertures [2,3,6] and when given a choice of path [7], suggesting that even when individuals approach an aperture at a faster than normal rate, their CP is maintained at 1.4 SW. The overall finding that running does not influence the CP when compared to walking is noteworthy. It appears that in voluntary path selection situations, consistent behaviors are maintained regardless of speed. Both groups exhibited similar CPs and made deviations from the walking path at the same distance from the obstacles. This null finding was not expected as it was hypothesized that
The authors declare no conflicts of interest. References [1] Higuchi T, Cinelli ME, Greig MA, Patla AE. Locomotion through apertures when wider space for locomotion is necessary: adaptation to artificially altered bodily states. Exp Brain Res 2006;175:50–9. [2] Hackney AL, Cinelli ME. Older adults are guided by their dynamic perceptions during aperture crossing. Gait Posture 2013;37:93–7. [3] Wilmut K, Barnett AL. Locomotor adjustments when navigating through apertures. Hum Mov Sci 2010;29:289–98. [4] Higuchi T, Murai G, Kijima A, Seya Y, Wagman JB, Imanaka K. Athletic experience influences shoulder rotations when running through apertures. Hum Mov Sci 2011;30:534–49. [5] Hackney AL, Cinelli ME. Young and older adults use similar body-scaled information during a non-confined aperture crossing task. Exp Brain Res 2013;225:419–29. [6] Warren WH, Whang S. Visual guidance of walking through apertures: bodyscaled information for affordances. J Exp Psychol 1987;13:371–83. [7] Hackney AL, Vallis LA, Cinelli ME. Action strategies of individuals during aperture crossing in non-confined space. Q J Exp Psychol 2013;66:1104–12.
Contents lists available at ScienceDirect
Gait & Posture journal homepage: www.elsevier.com/locate/gaitpost
Short Communication
The effects of specific athletic training on path selection while running Amy L. Hackney a, Allison Zakoor b, Michael E. Cinelli b,* a b
Department of Kinesiology, University of Waterloo, ON, Canada Department of Kinesiology and Physical Education, Wilfrid Laurier University, ON, Canada
A R T I C L E I N F O
A B S T R A C T
Article history: Received 27 February 2014 Received in revised form 15 September 2014 Accepted 20 September 2014
Apertures that are smaller than 1.3 times the shoulder width (SW) require that individuals make an adjustment to their normal walking behavior [6]. When given a choice, individuals will choose to avoid apertures smaller than this ratio, rather than rotate their shoulders and walk through [7]. Research has yet to determine whether this choice in path selection can be influenced by the speed at which one approaches the aperture or by experience/training. Therefore, the current study investigated whether approach speed and/or specific athletic training influences the choice in path selection. Specificallytrained athletes (n = 6) and non-trained (n = 6) young adults ran toward a visible goal placed at the end of the path and avoided an aperture (created by two poles) placed along the midline of the path. The separation between the poles ranged between 0.6 and 1.8 times each participant’s SW, in increments of 0.2. Participants were permitted to either run through or around the aperture to get to the end goal. Results demonstrated that regardless of training experience, participants ran around apertures smaller than 1.4 the SW and ran through apertures larger than this ratio. Increased approach speed (i.e., running) therefore appears to elicit similar aperture crossing behaviors as walking [2,3,6,7]. Additionally, when faced with the choice to run around or to run through apertures, individuals who are specificallytraining to run through small spaces chose similar paths as individuals who are not trained to do so. Therefore, specific training does not appear to influence voluntary path selection. ß 2014 Elsevier B.V. All rights reserved.
Keywords: Aperture crossing Path selection Action-scaled Athletic training
1. Introduction Passing through small spaces requires individuals to accurately perceive the size of the aperture relative to their body size and consider their action capabilities, including restraints on movement ability (sitting in a wheelchair) [1], movement variability [2,3] and approach speed. During locomotion, individuals must be aware of such constraints and adapt their movements accordingly. Research has suggested that experience can also influence aperture crossing performance. American football players initiate shoulder rotations closer to the aperture and produce smaller rotations compared to non-trained individuals when running through apertures but no differences exist when walking [4]. Since offensive players are trained to pass through the small spaces between the opponent’s defense while running, they likely have established a heightened awareness of body size. Furthermore, these athletes are likely more attuned to their action capabilities of passing through gaps due to practicing through spaces they may
* Corresponding author. Tel.: +1 519 884 0710x4217; fax: +1 519 747 4594. E-mail addresses: [email protected], [email protected] (M.E. Cinelli). http://dx.doi.org/10.1016/j.gaitpost.2014.09.018 0966-6362/ß 2014 Elsevier B.V. All rights reserved.
otherwise choose not to pass through. Therefore, when forced to pass through an aperture [4], performance can be influenced by experience/training however the question remains as to whether specific-training influences the voluntary choice to pass through apertures. The objective of this study was to determine whether individuals who have received specific-training choose to voluntarily pass through smaller apertures than their non-trained counterparts. Recent work demonstrates that when given the choice, nontrained individuals voluntarily chose to walk around obstacles too small for straight passage rather than pass through and rotate the shoulders [5]. The aperture width to SW ratio (A/S) that separated straight walking and avoidance situations was similar to the ratio that elicited a rotation during confined aperture crossing (1.3 SW) [5,6]. Therefore, it was hypothesized that all individuals in the current study would chose to run around apertures too small for straight passage however, specifically-trained participants would run through smaller relative spaces compared to the non-trained controls (athletes will have smaller critical points). Since research [4] demonstrated that football players only performed differently than non-football players when running, the second objective was to extend previous findings by identifying the CP which was not
A.L. Hackney et al. / Gait & Posture 41 (2015) 323–325
324
13m 5m
Aperture Width
Goal
Shoulder Width
Path option 1
Path option 2
Fig. 1. Birds-eye view of the experimental set-up with possible routes.
reported previously [5,7] and determine the influence of an increased approach speed on voluntary path selection.
measures ANOVAs were conducted to determine whether approach speed and/or onset of deviations differed between groups and/or aperture width.
2. Methods Specifically-trained offensive football players (n = 6 males) and non-trained participants (n = 6 (4 males)) provided informed consent. Participants were 20–23 years of age and had no physical/ neurological disability affecting the ability to walk/run and had not suffered a concussion within the last 3 years. Participants were instructed to run at their maximum speed along a 13 m pathway toward a goal and avoid two vertical poles placed halfway along the path (Fig. 1). Participants were given the option to run through or around the aperture but were told not to hit the poles. The width between the obstacles ranged from 0.6 to 1.8 each participant’s SW in increments of 0.2. Each aperture width was presented four times in randomized order for a total of 28 trials. Kinematic data was measured using the OptoTrak camera system (Northern Digital Inc., Waterloo) at a sampling frequency of 60 Hz with infrared light-emitting diodes (IREDs) placed on the head and the shoulders. The SW of each participant was measured to the nearest centimeter using a measure tape.
3. Results Both the frequency of path deviations and the M–L COM position at TOC decreased as the size of the aperture width increased (F(6,60) = 7.21, p < 0.05 and F(6,60) = 13.17, p < 0.01, respectively) however no effect of group was identified for frequency of path deviation (Fig. 2a) or M–L COM at TOC (Fig. 2b). Post hoc analysis determined that aperture widths 0.6–1.2 were different from straight walking (p < 0.05) for both groups for both the frequency of path deviations and the M–L COM position at TOC. Aperture widths 1.4–1.8 were not different from the straight walking values, suggesting that the CP for non-trained and trained athletes was
2.1. Data/statistical analysis Path selection was determined by the medial–lateral (M–L) position of the center of mass (COM) at the time of crossing (TOC) the obstacles. M–L COM values close to 0 cm represented straight walking trial whereas values larger than half of the absolute aperture widths were trials where the participant deviated around the obstacles. A frequency count of the total number of deviation trials at each width was calculated for both groups and an arcsin transformation converted the frequencies into parametric data. A 7(aperture width) 2(group) repeated measures ANOVA was conducted to identify whether the frequency of path deviations changed as a function of aperture width and/or group. The smallest width not significantly different from zero was considered the critical point (CP) for each group. To confirm the CP, the M–L COM position at the TOC was run through a 7(aperture width) 2(group) repeated measures ANOVA. The onset of path deviations was identified as the distance from the obstacles in which the M–L COM fell outside two standard deviations from the average straight running trials. Repeated
Fig. 2. (a) M–L COM position and (b) proportion of deviation trials at each aperture width for both the trained and non-trained groups.
A.L. Hackney et al. / Gait & Posture 41 (2015) 323–325 Table 1 Averages and standard deviations for all dependent variables.
325
1.4. The proportion explained by ‘Group’ is 0.103 and thus is not responsible for a high percentage of the variance of the scores. Onset of path deviation was not different between groups or aperture width. Additionally, approach speed did not differ between groups, although specificallytrained athletes showed a trend of running faster than their non-trained counterparts. Trained-athletes and non-athletes had similar SW. Table 1 displays all averages and standard deviations.
specifically-trained athletes would have smaller thresholds than non-trained participants and deviate closer to the aperture. It is possible that a lack of difference between groups was a result of the task itself. American football players are trained to forcefully fit through small spaces while running, but also choose the largest gap in close proximity to fit through. Previous work [4] required participants to pass through an aperture and measured the onset and necessary magnitude of rotation. The current study allowed participants to self-select the path and measured their actions. It is also possible that the null finding was due to not wearing shoulder pads. Trained athletes practice fitting through tight gaps at high speeds and do so with shoulder pads and therefore future work should consider such an effect. It appears that the effects of training previously observed during forced apertures crossings is not transferable to tasks where individuals are free to choose their path.
4. Discussion
Conflict of interest
Variable of interest
Specifically trained
Non-trained
Frequency of path deviation M-L COM position at TOC (m) Critical point Onset of path deviation (m) Approach speed (m/s) Shoulder width (cm)
0.71 (71%) 0.06 0.35 0.11 1.40 0.15 2.03 0.81 4.94 0.88) 52.8 3.2
0.68 (68%) 0.17 0.26 0.18 1.38 0.13 2.12 0.46 4.66 0.96 49.7 6.7
When presented with an aperture too small to pass through without a rotation, all participants ran around the obstacles. This is not surprising since research has demonstrated that individuals prefer to walk around obstacles that are too small for straight passage [7]. Additionally, all participants circumvented apertures smaller than 1.4 SW and ran through apertures larger than this ratio. This CP is similar to that observed when forced to walk through apertures [2,3,6] and when given a choice of path [7], suggesting that even when individuals approach an aperture at a faster than normal rate, their CP is maintained at 1.4 SW. The overall finding that running does not influence the CP when compared to walking is noteworthy. It appears that in voluntary path selection situations, consistent behaviors are maintained regardless of speed. Both groups exhibited similar CPs and made deviations from the walking path at the same distance from the obstacles. This null finding was not expected as it was hypothesized that
The authors declare no conflicts of interest. References [1] Higuchi T, Cinelli ME, Greig MA, Patla AE. Locomotion through apertures when wider space for locomotion is necessary: adaptation to artificially altered bodily states. Exp Brain Res 2006;175:50–9. [2] Hackney AL, Cinelli ME. Older adults are guided by their dynamic perceptions during aperture crossing. Gait Posture 2013;37:93–7. [3] Wilmut K, Barnett AL. Locomotor adjustments when navigating through apertures. Hum Mov Sci 2010;29:289–98. [4] Higuchi T, Murai G, Kijima A, Seya Y, Wagman JB, Imanaka K. Athletic experience influences shoulder rotations when running through apertures. Hum Mov Sci 2011;30:534–49. [5] Hackney AL, Cinelli ME. Young and older adults use similar body-scaled information during a non-confined aperture crossing task. Exp Brain Res 2013;225:419–29. [6] Warren WH, Whang S. Visual guidance of walking through apertures: bodyscaled information for affordances. J Exp Psychol 1987;13:371–83. [7] Hackney AL, Vallis LA, Cinelli ME. Action strategies of individuals during aperture crossing in non-confined space. Q J Exp Psychol 2013;66:1104–12.
