Comparison between high- and low-intensity eccentric cycling of equal mechanical work for muscle damage and the repeated bout effect.

Georgios Mavropalias,Oliver R Barley,Anthony J Blazevich,Wayne C K Poon,Aiden J Fisher,Kazunori Nosaka,Tomoko Koeda

doi:10.1007/s00421-020-04341-5

Georgios Mavropalias, Oliver R Barley + Show 5 more

Open Access

https://doi.org/10.1007/s00421-020-04341-5

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Abstract

We compared high- and low-intensity eccentric cycling (ECC) with the same mechanical work for changes in muscle function and muscle soreness, and examined the changes after subsequent high-intensity ECC. Twenty men performed either high-intensity ECC (1min × 5 at 20% of peak power output: PPO) for two bouts separated by 2weeks (H-H, n = 11), or low-intensity (4min × 5 at 5% PPO) for the first and high-intensity ECC for the second bout (L-H, n = 9). Changes in indirect muscle damage markers were compared between groups and bouts. At 24h after the first bout, both groups showed similar decreases in maximal isometric (70° knee angle, - 10.6 ± 11.8%) and isokinetic ( - 11.0 ± 8.2%) contraction torque of the knee extensors (KE), squat ( - 7.7 ± 10.4%) and counter-movement jump ( - 5.9 ± 8.4%) heights (p < 0.05). Changes in KE torque and jump height were smaller after the second than the first bout for both the groups (p < 0.05). Increases in plasma creatine kinase activity were small, and no significant changes in vastus lateralis or intermedius thickness nor ultrasound echo-intensity were observed. KE soreness with palpation was greater (p < 0.01) in H-H (peak: 4.2 ± 1.0) than L-H (1.4 ± 0.6) after the first bout, but greater in L-H (3.6 ± 0.9) than H-H (1.5 ± 0.5) after the second bout. This was also found for muscle soreness with squat, KE stretch and gluteal palpation. The high- and low-intensity ECC with matched mechanical work induced similar decreases in muscle function, but DOMS was greater after high-intensity ECC, which may be due to greater extracellular matrix damage and inflammation.

Highlights

Lengthening muscle actions are performed when activated muscles are lengthened by an external force
The high- and low-intensity eccentric cycling (ECC) with matched mechanical work induced similar decreases in muscle function, but delayed-onset muscle soreness (DOMS) was greater after high-intensity ECC, which may be due to greater extracellular matrix damage and inflammation
While many factors affect the magnitude of muscle damage and repeated bout effect (RBE) induced by eccentric exercise, exercise intensity appears to be a key factor; i.e., higher intensity eccentric actions induce greater damage than lower intensity ones (Nosaka and Newton 2002; Chen et al 2007, 2012; Hasenoehrl et al 2017; Tsuchiya et al 2019)

Summary

Introduction

Lengthening muscle actions (eccentric actions) are performed when activated muscles are lengthened by an external force. It has been well documented that exercises consisting of unaccustomed eccentric actions induce muscle damage (Clarkson et al 1992). Repeating the same exercise within several weeks after the initial bout results in smaller changes in these markers when compared with the initial bout, which is referred to as the repeated bout effect (RBE) (Nosaka and Clarkson 1995; Hortobágyi et al 1998; McHugh 2003). While many factors affect the magnitude of muscle damage and RBE induced by eccentric exercise, exercise intensity appears to be a key factor; i.e., higher intensity eccentric actions induce greater damage than lower intensity ones (Nosaka and Newton 2002; Chen et al 2007, 2012; Hasenoehrl et al 2017; Tsuchiya et al 2019).

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