Author(s): VATOVEC, R., KOZINC, Ž., VOGLAR, M., Institution: UNIVERSITY OF PRIMORSKA, FACULTY OF HEALTH SCIENCES , Country: SLOVENIA, Abstract-ID: 2112

INTRODUCTION:
Eccentric training is commonly prescribed to improve athletic performance. However, exercise-induced muscle damage (EIMD) is a potential limitation of eccentric training due to its detrimental impact on subsequent performance. Recovery strategies aimed at decreasing the negative impact of EIMD are commonly implemented following strenuous exercise. In this regard, foam rolling (FR) has shown promising effects in promoting recovery after EIMD [1]. On the other hand, the effects of FR prior to eccentric exercise on markers of EIMD are still unknown. In addition, EIMD has been recently associated with increased muscle stiffness [2], which could potentially serve as a marker of EIMD. The aim of this study was to investigate the effects of FR prior to intense eccentric exercise on measures of hamstring stiffness.
METHODS:
The study sample consisted of 14 healthy young adults (7 males, 7 females; age range = 18-35 years). We conducted a within-subject randomized controlled trial, in which one leg served as the intervention and the other as the control leg. Outcome measures were assessed at baseline, immediately after and one hour after eccentric exercise. Following baseline measurements, the participants completed an aerobic warm-up and a short bout of FR on the posterior thigh of intervention leg (2 × 60 s of FR at a predetermined tempo of 27 bpm). The eccentric training protocol included three sets of 10 repetitions of maximal eccentric knee extensions on an isokinetic dynamometer, followed by three sets of six repetitions of the Nordic hamstring exercise. Passive stiffness of the long head of biceps femoris (BF) and semimembranosus (SM) were measured via ultrasound-based shear wave elastography in a prestretched position, whereas passive knee extension torque (PKET) was measured on an isokinetic dynamometer. The data were analysed using the repeated measures analysis of variance (3×2) with two within-subject factors (time and condition). The margin for statistical significance was set at α=0.05. The effect size was expressed as η2 and interpreted as small (η2=0.01), moderate (η2=0.06) or large (η2=0.14).
RESULTS:
Our results showed a significant time effect for BF stiffness (p<0.001, η2=0.50) and PKET (p=0.002, η2=0.40). The time effect for SM stiffness was not significant (p=0.37, η2=0.07). Furthermore, we did not find a significant condition (p=0.17–0.60, η2=0.02–0.15) or interaction effect (time×condition) (p=0.08–0.49, η2=0.06–0.18) for none of the included outcome measures.
CONCLUSION:
Eccentric training leads to increased stiffness of the long head of BF and PKET. Moreover, a short bout of FR prior to eccentric exercise does not have a significant impact on changes of hamstring stiffness. It appears that FR does not decrease the amount of EIMD following eccentric exercise.
1. Wiewelhove et al. (2019) 2. Ličen & Kozinc (2022)