The effect of dominant first dorsal interosseous fatigue on the force production of a contralateral homologous and heterologous muscle

Crossover and non-local muscle fatigue (NLMF) has generally focused on large muscle groups. It is unclear whether fatigue of a small muscle can result in NLMF of a larger muscle. The purpose of the present study was to examine the effect of small muscle (first dorsal interosseous; FDI) fatigue on the force and activation of contralateral homologous and larger heterologous muscles (biceps brachii, BB). Fifteen right-handed, male subjects performed three pre-test index finger abduction or elbow flexion maximum voluntary isometric contractions (MVICs) on the non-dominant side. Subsequently, they performed two 100s index finger abduction MVICs on the dominant side (experimental [fatigue] group) or rested for 5 minutes (control group). Afterwards, a single MVIC and a 12 repetition MVIC fatiguing protocol were completed with index finger abduction or elbow flexion on the non-dominant side. Force and electromyography (EMG) were measured from both sides. The force and EMG (median frequency:MDF) of non-exercised index finger abductors (IFA)/FDI and elbow flexors (EF)/BB significantly decreased after the fatiguing protocol. Compared with the control condition, the non-exercised IFA (12.5% and 5.7%) had significantly greater force and MDF fatigue indexes than the EF (5.2% and 1.7%). There were no significant force differences with the single MVIC test between conditions. The small muscle fatiguing protocol produced NLMF effects on both contralateral homologous and larger heterologous muscles, with the force decrements greater with the homologous muscle.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author