Inertial flywheel knee- and hip-dominant hamstring strength exercises in professional soccer players: Muscle use and velocity-based (mechanical) eccentric overload.

Luis Suarez-Arrones,F Javier Núñez,Pilar Lara-Lopez,Alberto Méndez-Villanueva,Valter Di Salvo,Daniel Boullosa

doi:10.1371/journal.pone.0239977

Luis Suarez-Arrones, F Javier Núñez + Show 4 more

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https://doi.org/10.1371/journal.pone.0239977

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Abstract

The primary aim of the present study was to analyze mechanical responses during inertial knee- and hip-dominant hamstring strengthening exercises (flywheel leg-curl and hip-extension in conic-pulley), and the secondary aim was to measure and compare regional muscle use using functional magnetic resonance imaging. Mean power, peak power, mean velocity, peak velocity and time in the concentric (CON) and eccentric (ECC) phases were measured. The transverse relaxation time (T2) shift from pre- to post-exercise were calculated for the biceps femoris long (BFl) and short (BFs) heads, semitendinosus (ST) and semimembranosus (SM) muscles at proximal, middle and distal areas of the muscle length. Peak and mean power in flywheel leg-curl were higher during the CON than the ECC phase (p<0.01). ECC peak power was higher than CON phase (p<0.01) in conic-pulley hip-extension exercise, while mean power was higher during the CON than ECC phase (p<0.01). Flywheel leg-curl showed a higher T2 values in ST and BFs and BFl (p<0.05), while the conic-pulley hip-extension had a higher T2 values in the proximal region of the ST and BFl (p<0.05). In conclusion, ECC overload was only observed in peak power during the conic-pulley hip-extension exercise. Flywheel leg-curl involved a greater overall use of the 4 muscle bellies, more specifically in the ST and BFs, with a selective augmented activity (compared with the conic-pulley) in the 3 regions of the BFs, while conic-pulley hip-extension exercise selectively targeted the proximal and medial regions of the BFl. Physiotherapists and strength and conditioning coaches should consider this when optimizing the training and recovery process for hamstring muscles, especially after injury.

Highlights

Hamstring injuries are the most common soccer-related muscle injury [1,2] representing more than 37% of all soccer-related injuries and requiring long rehabilitation periods [1,2]
ECC time was higher than CON time (p
The main findings of the present study were: 1) CON mean power was always higher than ECC mean power in both exercises; 2) ECC overload was only observed in peak power during the Versa Pulley (VP); 3) VP allowed greater mean and peak power than LC, while players perceived a higher training load after LC exercise; 4) overall, changes in T2 values in most regions of the 4 muscle bellies, the BFs and semitendinosus muscle (ST), were greater during the knee-flexion exercise (LC); and 5) VP appeared more capable of selectively engaging the biceps femoris muscle [long head (BFl) proximal and medial regions while all regions of BFs were selectively used by the LC

Summary

Introduction

Hamstring injuries are the most common soccer-related muscle injury [1,2] representing more than 37% of all soccer-related injuries and requiring long rehabilitation periods [1,2]. Previous studies showed that the ST muscle could play a key role as the most important neuromuscular ACL agonist, suggesting that an increasing in ST muscle activity via neuromuscular training intervention can be a key part of ACL preventive strategy [9]. All this information helps to understand the importance of this muscle group for performance and from the point of view of both prevention of and recovery from injuries. Most preventive strategies aimed at decreasing hamstring and non-contact ACL injuries include some sort of neuromuscular training of the hamstring muscles as an essential aspect [10,11,12,13]

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