AUTHOR=Zhou Zixiang , Chen Chao , Chen Xin , Yi Wenjuan , Cui Weijia , Wu Rui , Wang Dexin 

TITLE=Lower extremity isokinetic strength characteristics of amateur boxers

JOURNAL=Frontiers in Physiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2022.898126

DOI=10.3389/fphys.2022.898126

ISSN=1664-042X

ABSTRACT=Aim: Sufficient strength and dynamic stability of the lower limbs are essential to improving punching force and preventing injury in amateur boxers. However, there are still no comprehensive reports on the isokinetic knee strength of boxers with different performance levels. The aims of the current study were to profile the isokinetic muscle strength of flexion and extension of the knee in boxers, as well as bilateral, unilateral, and functional ratios, and to investigate the variation in these muscle strength characteristics associated with different performance levels.

Methods: Boxers were divided in two performance groups, elite (5 males, 4 females) and non-elite group (5 males, 4 females). Muscle strength of the knee was determined via an IsoMed2000 device. Parameters examined included peak torque of the hamstring (H) and quadriceps (Q) during concentric (con) and eccentric (ecc) contractions at low (60°/S), medium (180°/S), and high (240°/S) speed, and bilateral ratios (BLs), unilateral ratios (ULs), and functional ratios of dominant (D) and non-dominant (ND) limbs.

Results: In all angular velocities, the peak torque of H and Q were stronger in the elite group than in the non-elite group. ULs were lower in the elite group than in the non-elite group in Hcon/Qcon at 180D (p < 0.01) and 180ND (p < 0.05), and in Hecc/Qecc at 60D, 180D (p < 0.05) and 240D (p < 0.01). The elite group had a higher BLs than the non-elite group in Hcon at 60°/S (p < 0.05), and Qcon at 180°/S (p < 0.05). The non-elite group had a higher functional ratio than elite boxers in Hecc/Qcon at 180D and 240D (p＜0.01). 
 
Conclusion: Elite boxers had stronger knee strength in con and ecc contractions. All boxers had normal Hecc/Qecc and Hcon/Qecc. Hcon/Qcon and Hecc/Qcon were abnormal at lower angular velocity. Elite boxers had higher BLs and lower ULs, indicating that they are at a higher risk of injury.