Acute Effects of Neuromuscular Electrical Stimulation Priming on Volleyball Spike Performance and Three-Dimensional Kinematics

Summary

This study examined the acute effects of neuromuscular electrical stimulation priming on volleyball spike performance and three-dimensional kinematics in male university volleyball players. Compared with the time-matched control group, the NMES conditioning group demonstrated greater ball velocity and phase-specific differences in lower-limb joint angles, segmental velocities, and shoulder–hip separation angle.

Abstract

Volleyball spiking is a complex explosive skill that requires coordinated force generation and transfer across the upper limbs, trunk, and lower limbs. Neuromuscular electrical stimulation (NMES) has been proposed as a preconditioning strategy for enhancing neuromuscular activation; however, its acute effects on phase-specific volleyball spike kinematics remain unclear. This study investigated the acute effects of NMES priming on spike performance and three-dimensional kinematics in male university volleyball players. Thirty participants were randomly assigned to an NMES conditioning group (n = 15) or a control group (n = 15). All participants completed a baseline spike assessment and a second assessment 72 h later. Immediately before the second assessment, the NMES group received 30 min of stimulation applied to the upper-limb muscles, including the deltoid, biceps brachii, and triceps brachii; the external oblique as a core muscle; and the vastus lateralis as a lower-limb muscle. The control group completed the same time-matched assessment without NMES. Three-dimensional kinematic data were collected using a synchronized four-camera three-dimensional motion-analysis system. The primary analysis compared performance and kinematic variables between the groups at the second assessment. Compared with the control group, the NMES group demonstrated greater ball velocity, smaller knee and ankle angles at bilateral-foot contact, greater hip, knee, and ankle angles at bilateral take-off, and higher thigh, calf, and foot segmental velocities. The NMES group also showed a smaller shoulder–hip separation angle at bilateral take-off and ball contact. These findings indicate that acute NMES priming applied to upper-limb, core, and lower-limb muscles may influence phase-specific joint configurations, lower-limb segmental velocities, and ball velocity during volleyball spiking. NMES may therefore have potential as a pre-performance neuromuscular activation strategy, although further studies using concealed allocation, blinded assessment, and direct group-by-time analyses are required.

Introduction

Volleyball is a competitive sport that relies heavily on explosive power and coordination, and spiking is one of the most important means of scoring¹. This technical movement places high demands on the athlete’s muscle output capacity, movement timing control, and neuromuscular control ability². A successful spike consists of three key stages: the run-up, take-off, and aerial hitting phases. Effective performance across these stages depends on coordinated force production and efficient energy transfer through the segments of the kinetic chain³. Previous studies have shown that hip-knee-ankle....

Protocol

Participants and eligibility criteria

The study protocol was approved by the Academic Ethics Committee of Jimei University (Approval No. JD02RS02406) and was conducted in accordance with the Declaration of Helsinki. Before enrollment, all participants received a detailed explanation of the study purpose, experimental procedures, potential risks, and their right to withdraw from the study at any time without penalty. Written informed consent was obtained from all participants before any study-related procedures were performed. Thirty healthy male university students with volleyball training experience were rec....

Results

Between-group differences in spike performance and kinematic parameters

Table 1 presents the between-group differences in volleyball spike performance and phase-specific kinematic parameters at the second assessment. Each group included 15 participants. During the aerial hitting phase, ball velocity at the moment of ball contact was significantly higher in the NMES conditioning group than in the control group (11.69 ± 2.14 vs. 9.95 ± 1.48 m/s; Z = &#.......

Discussion

The study investigated the acute effects of a single immediate NMES intervention on volleyball players’ spiking performance, with a focus on kinematic changes during the run-up, take-off, and aerial hitting phases. The results showed that when NMES was applied immediately to the lower limbs and key core muscle groups, participants’ joint angles, movement velocity, and ball velocity were significantly improved. This shows that NMES can instantly improve neuromuscular coordination and movement output efficiency.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Frequency-modulated pulse therapy device	Manufacturer not specified in the study records	Guangzhou, China	ZN-566
High-speed camera	Sony Corporation	Tokyo, Japan	PXW-FS7
SPSS	IBM	Armonk, NY, USA	Version 27 for Windows
Three-dimensional motion-analysis system	Visol Inc.	Gwangmyeong, Republic of Korea	Kwon3D