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Force–time course parameters and force fatigue model during an intermittent fatigue protocol in motorcycle race riders
Author(s) -
Marina M.,
Rios M.,
Torrado P.,
Busquets A.,
AnguloBarroso R.
Publication year - 2015
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12220
Subject(s) - muscle fatigue , forearm , muscular fatigue , mathematics , medicine , simulation , physical medicine and rehabilitation , materials science , physical therapy , surgery , electromyography , computer science
Fatigue in forearm muscles may be critical for motorcycle riders in relation to performance and forearm disorders. Force–time course parameters were examined to better characterize the reduction in the maximal force generating capacity ( MVC ) during an intermittent fatigue protocol ( IFP ) specifically designed for motorcycle riders. Also, a mathematical force fatigue model is proposed. Forty motorcyclists (aged 27.6 ± 6.8 years) performed an IFP that simulated the braking gesture and posture of a rider. Fatigue was confirmed by a 40% decrement of the normalized MVC in comparison with basal value. Contraction time increased in comparison with basal condition ( P ≤ 0.034). Relaxation kinetics presented two phases: (a) a pre‐fatigue phase where half relaxation time ( HRT raw ) and normalized ( HRT nor ) decreased ( P ≤ 0.013) while relaxation rate ( RR raw ) remained unchanged; and (b) a fatiguing phase where HRT raw , HRT nor increased and RR raw decreased ( P ≤ 0.047). Normalized RR raw ( RR nor ) declined progressively ( P ≤ 0.016). The proposed nonlinear force fatigue model confirmed a satisfactory adjustment ( R 2 = 0.977 ± 0.018). This mathematical expression derived three patterns of force fatigue: three‐phase, exponential and linear, representing 70%, 13%, and 17% of the participants, respectively. Overall, these results provided further support to force fatigue theoretical and applied proposals.