Training and contralateral effects of 6 weeks isokinetic eccentric exercise on plantarflexor muscle-tendon mechanics

Description

INTRODUCTION: Large increases in joint range of motion (ROM) have been reported after eccentric resistance training [1], however limited data exist on the potential mechanisms associated with these changes. Furthermore, while the contralateral effects of eccentric training are well documented for strength [2], no data exist for ROM. Therefore, the present study examined the training and contralateral effects of a 6-week isokinetic eccentric plantarflexor training programme on muscle-tendon mechanics.

METHODS: Before and after the 6-week programme, dorsiflexion ROM, stretch tolerance, elastic energy, plantarflexor muscle-tendon stiffness, gastrocnemius medialis (GM) architecture, and maximal isometric plantarflexor torque were measured using dynamometry and sonography in both lower limbs of 13 participants (5 males, 8 females, age [mean ± SD] = 22.1±2.4 y, height = 1.7±0.1 m, mass = 71.3±16.2 kg). Training was performed twice-weekly on the right limb, consisting of 5 sets of 12 maximal isokinetic eccentric plantarflexor contractions performed at a 10°·s-1 velocity through a 30° ROM, with each contraction terminating at full passive dorsiflexion ROM.

RESULTS: Significant (P
CONCLUSION: The large increase in ROM after eccentric resistance training was associated with changes in neurological, mechanical, and structural adaptations in the trained limb, with evidence of a contralateral effect primarily being associated with a neurological (stretch tolerance) adaptation. The substantial and similar increases in isometric strength in both the trained and contralateral limbs are consistent with a previous review [2] confirming a stronger contralateral effect following eccentric resistance training than other contraction modes. The large changes in structural and functional measures combined with substantial changes in the contralateral limb have important implications for exercise prescription in healthy and clinical (e.g. injured, diseased, aged) populations where periods of inactivity may negatively influence these outcome measures.

REFERENCES
1.Kay et al. Med Sci Sports Exerc. 2023;doi:10.1249/MSS.0000000000003085
2.Cirer-Sastre et al. J Sports Sci Med. 2017;16:180-186.

Period	7 Jul 2023
Event title	28th Annual Congress of the European College of Sport Science (ECSS)
Event type	Conference
Location	Paris, FranceShow on map
Degree of Recognition	International