Muscle fiber typology substantially influences time to recover from high-intensity exercise
Eline Lievens japplphysiol 30 JAN 2020
Human fast-twitch muscle fibers generate high power in a short amount of time but are easily fatigued, while slow-twitch fibers are more fatigue resistant. The transfer of this knowledge to coaching, is hampered by the invasive nature of the current evaluation of the muscle typology by biopsies. Therefore, a non-invasive method was developed to estimate muscle typology through proton magnetic resonance spectroscopy in the gastrocnemius. The aim of this study was to investigate if male subjects with an a priori determined fast typology (FT) are characterized with a more pronounced Wingate exercise-induced fatigue and delayed recovery compared to the ones with a slow typology (ST).
Ten subjects with an estimated higher percentage of fast fibers and 10 subjects with an estimated higher percentage of slow fibers underwent the test protocol, consisting of three 30 sec all-out Wingate tests. Recovery of knee extension torque was evaluated by maximal voluntary contraction combined with electrical stimulation up to 5 h after the Wingate tests. Although both groups delivered the same mean power across all Wingates, the power drop was higher in the FT group (-61%) compared to the ST group (-41%).
The torque at maximal voluntary contraction had fully recovered in the ST group after 20 min, while the FT group had not yet recovered 5 h into recovery. This non-invasive estimation of muscle typology can predict the extent of fatigue and time to recover following repeated all-out exercise and may have applications as a tool to individualize training and recovery cycles.
