# Effects of relaxation training after volleyball exercise on blood lactate concentration, muscle hardness, and heart rate

## TL;DR

This study finds that guided relaxation training improves recovery in volleyball athletes compared to passive rest, based on blood lactate, muscle hardness, heart rate, and soreness.

## Contribution

The study introduces guided relaxation training as a superior recovery method for volleyball athletes using multidimensional physiological and subjective measures.

## Key findings

- Relaxation training significantly lowers blood lactate levels compared to passive rest after volleyball exercise.
- Muscle hardness and heart rate recovery improve more with relaxation training than passive rest.
- Athletes report better overall recovery and less soreness with guided relaxation training.

## Abstract

Volleyball recovery optimisation is not a well-studied topic although recovery is physiologically demanding. This experiment was conducted to determine the effectiveness of guided relaxation training over passive rest based on biochemical, mechanical and autonomic recovery measures.

A total of 600 adolescent volleyball athletes (16.8 ± 1.1 years) were recruited across four training centres in China. Participants completed both relaxation and passive recovery conditions in a randomised crossover design, with a one-week washout between sessions. Blood lactate, muscle hardness (via Myoton), heart rate recovery at 60 s (HRR60s), total quality recovery (TQR), and soreness using a visual analogue scale (VAS) were measured at baseline, T1 (immediate post), T2 (15 min), and T3 (30 min). Nonparametric comparisons (Mann–Whitney U test) and an aligned rank transform analysis of variance (ANOVA) were used for between-group and within-group analyses, respectively.

At T3, mean lactate was significantly lower in the relaxation group (2.02 ± 0.72 mmol/L) than passive rest (2.76 ± 0.81 mmol/L; U = 34,011, p = 0.001). Muscle hardness reduction was greater in the relaxation group (−18.04 ± 7.12 N/m) compared to passive rest (−11.12 ± 6.87 N/m; U = 36,291, p = 0.002). HRR60s improved more markedly in the relaxation group (+31.84 ± 6.72 bpm vs. +26.91 ± 7.20 bpm; U = 33,712, p = 0.001). TQR scores were higher (15.9 ± 1.6 vs. 14.7 ± 1.9; U = 32,598, p = 0.001) and VAS soreness lower (2.4 ± 1.2 vs. 3.1 ± 1.4; U = 35,811, p = 0.001) under relaxation.

Relaxation training enhances multidimensional recovery outcomes in competitive volleyball athletes.