Effect of the Knee and Hip Angles on Knee Extensor Torque: Neural, Architectural, and Mechanical Considerations.

Patrizio Canepa,Christos Paizis,Romuald Lepers,Yoann M Garnier,Alain Martin

doi:10.3389/fphys.2021.789867

Patrizio Canepa, Christos Paizis + Show 3 more

Open Access

https://doi.org/10.3389/fphys.2021.789867

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Abstract

This study examined the influence of knee extensors’ hip and knee angle on force production capacity and their neuromuscular and architectural consequences. Sixteen healthy men performed sub-maximal and maximal voluntary isometric contractions (MVIC) of knee extensors with four different combinations of the knee and hip angles. Muscle architecture, excitation-contraction coupling process, muscular activity, and corticospinal excitability were evaluated on the vastus lateralis (VL) and rectus femoris (RF) muscles. MVIC and evoked peak twitch (Pt) torques of knee extensors increased significantly (p < 0.05) by 42 ± 12% and 47 ± 16% on average, respectively, under knee flexed positions (110° flexion, 0° = full extension) compared to knee extended positions (20° flexion) but were not different between hip positions (i.e., 0° or 60° flexion). Knee flexion also affected VL and RF muscle and fascicle lengths toward greater length than under knee extended position, while pennation angle decreased for both muscles with knee flexion. Pennation angles of the VL muscle were also lower under extended hip positions. Alternatively, no change in maximal muscle activation or corticospinal activity occurred for the VL and RF muscles across the different positions. Altogether these findings evidenced that MVIC torque of knee extensors depended particularly upon peripheral contractile elements, such as VL and RF muscle and fascicle lengths, but was unaffected by central factors (i.e., muscle activation). Furthermore, the hip position can affect the pennation angle of the VL, while VL muscle length can affect the pennation angle of the RF muscle. These elements suggest that the VL and RF muscles exert a mutual influence on their architecture, probably related to the rectus-vastus aponeurosis.

Highlights

Consistent findings demonstrate the influence that the knee joint exerts angle on the knee extensors’ maximal torque production capacity
No main effect was detected for the RMSMVIC/M ratio for both the vastus lateralis (VL) (p = 0.265; ηp2 = 0.089) and the rectus femoris (RF) muscles (p = 0.186; ηp2 = 0.115; see Table 1)
This increase in corticospinal activity could be explained by a greater muscle activity transcribed by the higher RMSMEP/RMSMVIC ratio observed both for the VL and RF muscle, suggesting that neural drive during voluntary

Summary

Introduction

Consistent findings demonstrate the influence that the knee joint exerts angle on the knee extensors’ maximal torque production capacity. Because the RF muscle originates from the acetabulum, a change in hip joint position could influence the knee joint’s torque due to the bi-articular RF muscle’s contribution (Herzog and ter Keurs, 1988). This model was further validated by the greater MVIC torque developed in a seated compared to a supine position (i.e., flexed vs extended hip position; Maffiuletti and Lepers, 2003; Rochette et al, 2003; Ema et al, 2017), while others did not find a difference between these two positions (Bampouras et al, 2017; Cavalcante et al, 2021). Contrary to the general agreement about the influence of knee joint angle on knee extensor’s MVIC, the effect of hip joint angle remains discussed

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