Pedaling Asymmetries in Cyclists With Unilateral Transtibial Amputation: Effect of Prosthetic Foot Stiffness

2011 ◽  
Vol 27 (4) ◽  
pp. 314-321 ◽  
Author(s):  
W. Lee Childers ◽  
Robert S. Kistenberg ◽  
Robert J. Gregor
Keyword(s):  
Time Trial ◽  
Transtibial Amputation ◽  
Intact Group ◽  
Prosthetic Foot ◽  
Unique Model ◽  
Simulated Time

Cyclists with unilateral transtibial amputation (CTA) provide a unique model to study integration of the neuromuscular and bicycle systems while having the option to modify this integration via the properties of the prosthesis. This study included eight CTA and nine intact cyclists. The cyclists pedaled on a stationary bicycle with instrumented force pedals. The CTA group pedaled with a stiff or flexible prosthetic foot during a simulated time trial and a low difficulty condition. During the time trial condition, pedaling with the flexible foot resulted in force and work asymmetries of 11.4% and 30.5%, the stiff foot displayed 11.1% and 21.7%, and the intact group displayed 4.3% and 4.2%, respectively. Similar trends were shown in the low difficulty condition. These data suggest foot stiffness has an effect on cycling symmetry in amputees.

scholarly journals Effectiveness of force production in persons with unilateral transtibial amputation during cycling

2011 ◽  
Vol 35 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Walter Lee Childers ◽  
Robert J Gregor
Keyword(s):  
Controlled Trial ◽  
Force Production ◽  
Time Trial ◽  
Future Research ◽  
Transtibial Amputation ◽  
Intact Group ◽  
Prosthetic Foot ◽  
Cycling Time Trial ◽  
Reaction Forces ◽  
Global Strategies

Background: Few published reports exist regarding the control of the human/prosthesis interface in persons with unilateral transtibial amputation. Objective: To investigate strategies employed by prosthetic users in controlling the human/prosthesis interface to highlight challenges associated with either the amputation or the design of the prosthesis. Study Design: Randomized controlled trial. Methods: Cycling was used as the locomotor task to allow for better control of task mechanics compared to walking. A group of nine cyclists with intact limbs were compared to eight cyclists with transtibial amputation (CTA) during a simulated cycling time trial. The CTA group pedaled with a stiff and flexible prosthetic foot. Reaction forces between the foot and the pedal were measured using an instrumented pedal system. The force effectiveness (FE) ratio was used as the measure of task performance. The FE ratio is the force component normal to the bicycle crank arm divided by the resultant force for both limbs and is commonly used to analyze pedaling technique. Results: The CTA group was equally as effective at applying forces as the intact group. Conclusions: These data suggest that individuals with lower limb loss are able to compensate for their amputation to utilize a similar pedaling technique for locomotor performance. As global strategies, e.g. force effectiveness, appear similar between groups future research should focus on local strategies, e.g. individual joint kinematics and kinetics.

scholarly journals Brain mapping after prolonged cycling and during recovery in the heat

2013 ◽  
Vol 115 (9) ◽  
pp. 1324-1331 ◽  
Author(s):  
Kevin De Pauw ◽  
Bart Roelands ◽  
Uroš Marušič ◽  
Helio Fernandez Tellez ◽  
Kristel Knaepen ◽  
...  
Keyword(s):  
Cold Water ◽  
Water Immersion ◽  
Time Trial ◽  
Insular Cortex ◽  
Cycling Performance ◽  
Cold Water Immersion ◽  
Active Recovery ◽  
Somatosensory Information ◽  
Postexercise Recovery ◽  
Simulated Time

The aim of this study was to determine the effect of prolonged intensive cycling and postexercise recovery in the heat on brain sources of altered brain oscillations. After a max test and familiarization trial, nine trained male subjects (23 ± 3 yr; maximal oxygen uptake = 62.1 ± 5.3 ml·min−1·kg−1) performed three experimental trials in the heat (30°C; relative humidity 43.7 ± 5.6%). Each trial consisted of two exercise tasks separated by 1 h. The first was a 60-min constant-load trial, followed by a 30-min simulated time trial (TT1). The second comprised a 12-min simulated time trial (TT2). After TT1, active recovery (AR), passive rest (PR), or cold water immersion (CWI) was applied for 15 min. Electroencephalography was measured at baseline and during postexercise recovery. Standardized low-resolution brain electromagnetic tomography was applied to accurately pinpoint and localize altered electrical neuronal activity. After CWI, PR and AR subjects completed TT2 in 761 ± 42, 791 ± 76, and 794 ± 62 s, respectively. A prolonged intensive cycling performance in the heat decreased β activity across the whole brain. Postexercise AR and PR elicited no significant electrocortical differences, whereas CWI induced significantly increased β3 activity in Brodmann areas (BA) 13 (posterior margin of insular cortex) and BA 40 (supramarginal gyrus). Self-paced prolonged exercise in the heat seems to decrease β activity, hence representing decreased arousal. Postexercise CWI increased β3 activity at BA 13 and 40, brain areas involved in somatosensory information processing.

Comparisons of Models of Cognitive Strategies During a Cycling Maximal Test and Simulated Time Trial

2007 ◽  
Vol 39 (Supplement) ◽  
pp. S411
Author(s):  
Brian Curry ◽  
Daniel B. Hollander ◽  
Jennifer J. Jeansonne ◽  
Ralph Wood ◽  
Edward P. Hebert
Keyword(s):  
Cognitive Strategies ◽  
Time Trial ◽  
Simulated Time

scholarly journals Time course of performance changes and fatigue markers during intensified training in trained cyclists

2002 ◽  
Vol 93 (3) ◽  
pp. 947-956 ◽  
Author(s):  
Shona L. Halson ◽  
Matthew W. Bridge ◽  
Romain Meeusen ◽  
Bart Busschaert ◽  
Michael Gleeson ◽  
...  
Keyword(s):  
Time Course ◽  
Time Trial ◽  
Exercise Stress ◽  
Maximal Heart Rate ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Plasma Urea ◽  
Cycling Efficiency ◽  
Perception Of Effort ◽  
Simulated Time

To study the cumulative effects of exercise stress and subsequent recovery on performance changes and fatigue indicators, the training of eight endurance cyclists was systematically controlled and monitored for a 6-wk period. Subjects completed 2 wk of normal (N), intensified (ITP), and recovery training. A significant decline in maximal power output (N = 338 ± 17 W, ITP = 319 ± 17 W) and a significant increase in time to complete a simulated time trial (N = 59.4 ± 1.9 min, ITP = 65.3 ± 2.6 min) occurred after ITP in conjunction with a 29% increase in global mood disturbance. The decline in performance was associated with a 9.3% reduction in maximal heart rate, a 5% reduction in maximal oxygen uptake, and an 8.6% increase in perception of effort. Despite the large reductions in performance, no changes were observed in substrate utilization, cycling efficiency, and lactate, plasma urea, ammonia, and catecholamine concentrations. These findings indicate that a state of overreaching can already be induced after 7 days of intensified training with limited recovery.

Examination of a Computer-simulated Time-trial to Assess Cycling Performance

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 731-732
Author(s):  
Michael J. Saunders ◽  
Tiffany L. Acker ◽  
Rachel L. Ondek ◽  
Brooke M. Shafer ◽  
Qingnian Goh ◽  
...  
Keyword(s):  
Time Trial ◽  
Cycling Performance ◽  
Simulated Time

Relating minimum toe clearance to prospective, self-reported, trip-related stumbles in the community

2016 ◽  
Vol 41 (4) ◽  
pp. 387-392 ◽  
Author(s):  
Noah J Rosenblatt ◽  
Angela Bauer ◽  
Mark D Grabiner
Keyword(s):  
Gait Analysis ◽  
Vertical Displacement ◽  
Gait Training ◽  
Risk Of Falling ◽  
Transtibial Amputation ◽  
Prosthetic Foot ◽  
Increased Risk ◽  
Increase Risk ◽  
Transtibial Amputees ◽  
Future Work

Background:Individuals with transtibial amputation are at increase risk of falling. The absence of an ankle joint and the associated musculature in these individuals can reduce clearance between the prosthetic foot and ground during the swing phase of gait, which may increase the risk of stumbling and in turn falling.Objectives:To associate minimum toe clearance during gait in the laboratory with community-based, trip-related stumbles by individuals with transtibial amputation using conventional feet.Study design:Prospective cohort design; following quantitative gait analysis, participants completed electronic surveys to prospectively report stumbles and falls for 1 year thereafter.Methods:General community with gait analysis conducted within a motion analysis laboratory and prospective tracking of stumbles occurring in the community. A volunteer sample of eight unilateral, transtibial amputees that were K3 or K4 level ambulators and current patients at a local prosthetic clinic. All participants completed the entire 1-year follow-up study. Prosthetic-side minimum toe clearance while walking on a level treadmill at self-selected speed and self-reported trip-related stumbles in the community. Minimum toe clearance was defined as a local minimum of the vertical displacement of the toe from toe-off to heelstrike relative to its position during midstance.Results:Prosthetic-side minimum toe clearance was more than 50% lower for participants who reported one or more trip-related stumbles on that side compared with participants who reported zero trip-related stumbles on the prosthetic side (minimum toe clearance = 12.3 ± 0.8 mm vs 25.6 ± 5.4 mm, respectively; p = 0.036).Conclusion:This is the first study relating laboratory-based measures to prospective stumbles by prosthesis users. The results suggest that prosthesis users with low minimum toe clearance may be at increased risk of experiencing a trip-related stumble in the community. Given that frequent stumbling increases the risk of falling, future work is warranted on the effectiveness of interventions focused on minimum toe clearance on reducing fall risk.Clinical relevanceInterventions to increase minimum toes clearance, which could include prescription of active dorsiflexing prostheses or gait training, may help reduce the risk of trip-related falls for individuals who report a history of trip-related stumbles.

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