Relationship of the knee extensor strength but not the quadriceps femoris muscularity with sprint performance in sprinters: a reexamination and extension

Miyuki Hori,Masafumi Terada,Mitsuo Otsuka,Takahiro Tanaka,Yuki Kusagawa,Tadao Isaka,Tadashi Suga,Akinori Nagano

doi:10.1186/s13102-021-00293-1

Abstract

PurposeThis study examined the relationships of knee extensor strength and quadriceps femoris size with sprint performance in sprinters.MethodsFifty-eight male sprinters and 40 body size-matched male non-sprinters participated in this study. The knee extensor isometric and isokinetic strengths were measured using a dynamometer. The isokinetic strength measurements were performed with slow and fast velocities at 60°/s and 180°/s, respectively. The quadriceps femoris muscle volume (MV) was measured using magnetic resonance imaging. The relative knee extensor strengths and quadriceps femoris MV were calculated by normalizing to body mass.ResultsAbsolute and relative knee extensor strengths during two velocity isokinetic contractions, but not during isometric contraction, were significantly higher in sprinters than in non-sprinters (P = 0.047 to < 0.001 for all). Such a significant difference was also observed for relative quadriceps femoris MV (P = 0.018). In sprinters, there were positive correlations between all three knee extensor strengths and quadriceps femoris MV (r = 0.421 to 0.531, P = 0.001 to < 0.001 for all). The absolute and relative strengths of the fast-velocity isokinetic knee extension correlated negatively with personal best 100-m sprint time (r = −0.477 and −0.409, P = 0.001 and < 0.001, respectively). In contrast, no such significant correlations were observed between absolute and relative quadriceps femoris MVs and personal best 100-m sprint time.ConclusionsThese findings suggest that despite the presence of the relationship between muscle strength and size, the knee extensor strength may be related to superior sprint performance in sprinters independently of the quadriceps femoris muscularity.

Highlights

Superior sprint performance is achieved using gross torques of the lower limb joints [1]
A recent study by Miller et al [10] reported that isometric knee extensor strength did not correlate with 100-m sprint performance in 31 male sprinters, which was a relatively large sample size. These findings suggest that isokinetic strength, rather than isometric strength, of knee extension may be a more important variable for superior sprint performance in sprinters
Fast-velocity isokinetic strength, but not isometric and slow-velocity isokinetic strengths, of the knee extension relative to quadriceps femoris muscle volume (MV) was significantly higher in sprinters than in non-sprinters (d = 0.42, P = 0.044)

Summary

Introduction

Superior sprint performance is achieved using gross torques of the lower limb joints [1]. The knee extensor torque contributes to accelerating the center of mass of the body and maintaining the height of the center of mass of the body during the stance phase while sprinting [1,2,3]. These roles of the knee extensor torque help increasing peak vertical ground reaction forces during sprinting [1,2,3], which is a major determinant of sprint performance [4, 5]. The knee extensor strength may be an important variable for achieving superior sprint performance in sprinters

Methods

Results

Conclusion