Published in:
01-04-2017 | Original Article
The effect of prior knowledge of test endpoint on non-local muscle fatigue
Published in: European Journal of Applied Physiology | Issue 4/2017
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Introduction
If the work duration or volume is known, it is common for individuals to anticipate this challenge by pursuing a strategy that may decrease the initial force output and maintain a force level that ensures a force reserve towards the end of the task. However, it is unknown whether this is a global strategy that is transferred to a non-exercised muscle following fatigue of a contralateral homologous muscle.
Methods
To clarify if prior knowledge of task endpoint has an effect on non-local muscle fatigue (NLMF), 15 male participants (22.4 ± 3.8 years) completed four conditions: (1) KNtest > fatigue (known endpoint after fatigue), (2) UNKtest > fatigue (unknown endpoint after fatigue), (3) KNtest > control (known endpoint without fatigue), (4) UNKtest > control (unknown endpoint without fatigue). For fatigue conditions, a maximal intensity, unilateral knee extension protocol was completed (two sets of 100 s maximal voluntary isometric contractions (MVIC) with 60 s rest between), whereas the control condition involved rest (260 s). The participants were either informed (known (KN) conditions) or not informed (unknown (UNK) conditions) of the duration of a post-intervention strength–endurance test (contralateral knee extension MVIC, ≥30 s).
Results
During the strength–endurance test, the UNKtest > fatigue displayed meaningful decreases in force (UNKtest > fatigue 10–12% over first 30 s), which was largest at the 25–30-s period (UNKtest > fatigue 7.4–41.1% from 25 to 1930s) compared to KNtest > fatigue and KNtest > control conditions, respectively.
Conclusion
Prior knowledge of task endpoint can modify NLMF and affect pacing strategies.