Alan R Hamilton1, David G Behm2. 1. Kinesiology, School of Human Kinetics and Recreation, Memorial University of Newfoundland, 230 Elizabeth Ave., St. John's, NL, A1C 5S7, Canada. 2. Kinesiology, School of Human Kinetics and Recreation, Memorial University of Newfoundland, 230 Elizabeth Ave., St. John's, NL, A1C 5S7, Canada. dbehm@mun.ca.
Abstract
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.
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.
Authors: Markus Amann; Massimo Venturelli; Stephen J Ives; John McDaniel; Gwenael Layec; Matthew J Rossman; Russell S Richardson Journal: J Appl Physiol (1985) Date: 2013-05-30
Authors: D G Behm; E M Colwell; G M J Power; H Ahmadi; A S M Behm; A Bishop; C Murph; J Pike; B McAssey; K Fraser; S Kearley; M Ryan Journal: Eur J Appl Physiol Date: 2019-11-06 Impact factor: 3.078
Authors: David G Behm; Shahab Alizadeh; Saman Hadjizedah Anvar; Courtney Hanlon; Emma Ramsay; Mohamed Mamdouh Ibrahim Mahmoud; Joseph Whitten; James P Fisher; Olaf Prieske; Helmi Chaabene; Urs Granacher; James Steele Journal: Sports Med Date: 2021-04-05 Impact factor: 11.136