Effect of vastus lateralis fatigue on load sharing between quadriceps femoris muscles during isometric knee extensions

Abstract

The present study aimed to investigate the effects of selective fatigue (i.e., one muscle of the quadriceps) on load sharing strategies during submaximal knee extensions. Shear wave elastography was used to measure muscle shear elastic modulus, as this is considered to be an index of individual muscle force. Sixteen participants attended two experimental sessions that each involved six 10-s knee extensions at 20% of maximal voluntary contraction (MVC) followed by a sustained submaximal isometric knee extension at 20% of MVC, until task failure (Tlim). Between the 10-s contractions and Tlim, participants were required to rest (5 min) for the control session or underwent 5 min of electromyostimulation (EMS) on vastus lateralis (EMS session). Compared with the control session, vastus lateralis shear elastic modulus values were significantly lower after EMS considering both the start of Tlim (54.6 ± 11.8 vs. 68.4 ± 19.2 kPa; P = 0.011) and the entire Tlim contraction (59.0 ± 14.0 vs. 74.4 ± 20.3 kPa; P = 0.019). However, no significant differences were observed for the other recorded muscles (vastus medialis and rectus femoris; both P = 1), i.e., different patterns of changes were found between participants. In conclusion, this study demonstrates that prefatiguing a single agonist muscle does not lead to a consistent redistribution of load sharing among the quadriceps muscles between individuals. These results suggest that the central nervous system does not use a common principle among individuals to control load sharing when neuromuscular fatigue occurs.

Nature of the coupling between neural drive and force-generating capacity in the human quadriceps muscle

“…Although we cannot rule out the possible influence of methodological issues such as crosstalk and amplitude cancellation, we do not believe that it would be significantly different between VM and VL. To support our assertion, a study that used elastography, which is insensitive to both crosstalk and amplitude cancellation, suggested a more variable force production in VM than VL across repeated isometric knee extensions [31]. It is, therefore, likely that this variability has a neurophysiological basis that might be related to the fact that in addition to knee extension, VM contributes to the control of the patellofemoral joint.…”

Shear-Wave Elastography Assessments of Quadriceps Stiffness Changes prior to, during and after Prolonged Exercise: A Longitudinal Study during an Extreme Mountain Ultra-Marathon

“…It is worth noting that lower quadriceps shear modulus values were obtained during a subsequent submaximal isometric torque-matched task [83], as shear modulus values are an indicator of lower force production caused by quadriceps muscle fatigue. However, neuromuscular fatigue does not necessarily correlate with running distance, as it was less prominent among the runners who completed the Tor des Géants than those who completed shorter MUMs [50].…”

Futsal Match-Related Fatigue Affects Running Performance and Neuromuscular Parameters but Not Finishing Kick Speed or Accuracy

“…The uncoupling between VA and RMS responses might be a result of the characteristic of the measures, since VA is the sum of the responses of all the knee extensor muscles to the superimposed motor nerve stimulation, while the EMG is a muscle-specific index (Girard et al, 2015b). Furthermore, it is possible that the load sharing strategies of quadriceps femoris could be altered under fatigue and contribute to maintenance of the RMS value of the vastus lateralis muscle after the simulated game (Bouillard et al, 2014). …”