Examining the relationship between lower limb muscular strength and endurance performance

Introduction

Recent findings have revealed a relationship between resistance training and endurance performance in both trained and untrained individuals. This has been attributed to the increase in myofibre size as well as accompanied changes in contractile elements that result following strength training. However, the effects of muscular strength on factors affecting endurance performance in competition settings (e.g. swimming) have not been significant. The purpose of the present study was to investigate the relationship between muscular strength and endurance performance in laboratory and field settings.

Methods

34 healthy male adults (age 21.62.5 years, BMI 24.42.2) performed three maximal oxygen consumption () assessments using a treadmill test (TT), the 20m Multistage Shuttle Run Test (20mMST), and the 20m Square Shuttle Run Test (20mSST). Data evaluating lower extremity muscular strength were obtained using knee flexion (PTF) and extension (PTE) isokinetic dynamometry at 60·sec-1. Total peak torque (PTT) generated was also calculated. Controlling for , General Linear Model (GLM) framework was adopted to identify potential causality of muscular strength on endurance performance.

Results

Performance in the TT demonstrated only a moderate linear relationship with PTF (p<0.05), while PTT remained positive but non-significant (p>0.05). Concurrently, performance in the 20mMST correlated with the PTT at r=0.63 (p<0.001), while the equivalent for 20mSST was significant at r=0.44 (p<0.05). Controlling for gold standard (i.e. TT) , stepwise GLM analyses revealed that the inclusion of leg strength parameters increased the coefficient of determination (R2) by 9% (p<0.001) and 4% (p<0.05) in predicting 20mMST and 20mSST performance, respectively.

Discussion/Conclusions

The present results suggest that individuals possessing greater lower extremity strength are likely to perform better in endurance activities - independently of - compared to individuals with inferior lower extremity strength levels. The latter may be attributed to adaptations from increased strength on lactate threshold (LT) and myofibre size. Increased muscular strength allows for a more efficient utilization of by increasing LT, where an increase in myofibre size improves type I fibre utilization allowing endurance athletes to delay the recruitment of other fibres [1]. A significant portion of endurance performance relies on lower extremity muscular strength in both laboratory- and field-based settings.
References
[1].Tanaka et al. (1998). Sports Medicine, 3: 191-200.