Sympathetic Nerve Activity and Strength Gains in Resistance Versus Concurrent Training (SKNA-CT)

Sympathetic Activation and Strength Gains Rise Together Under Resistance Training But Uncouple Under Concurrent Training: An 8-Week Randomized Controlled Trial in Untrained Men

This study examines how the body's stress (sympathetic) nervous system responds to 8 weeks of either strength training alone or strength training combined with endurance (treadmill running) training in previously untrained young men. Skin sympathetic nerve activity, a noninvasive marker of sympathetic nervous system activity, is measured before and after training, along with muscle strength, jumping ability, and heart rate variability. The study investigates whether changes in sympathetic nervous system activity are associated with changes in strength and jumping ability, and whether this relationship differs between men who perform strength training alone versus those who combine strength and endurance training.

Study Overview

• Status: Completed
• Conditions: Sympathetic Nervous System
• Intervention / Treatment: Other: Strength-only training; Other: Concurrent training

Detailed Description

This study examined how the body's stress (sympathetic) nervous system responds to 8 weeks of either strength training alone or strength training combined with endurance (treadmill running) training in previously untrained young men. Skin sympathetic nerve activity, a noninvasive marker of sympathetic nervous system activity, was measured before and after training, along with muscle strength, jumping ability, and heart rate variability. The study found that in men who did strength training only, those whose sympathetic nervous system activity increased the most also gained the most strength and jumping ability. This relationship was not seen, and in some cases reversed, in men who combined strength training with endurance training. The findings suggest that adding endurance exercise changes how the nervous system adapts to a strength training program, alongside the well-documented reduction in strength gains seen with combined training (the "interference effect").

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Beijing, China, 100091
    • Beijing sport University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy young men
• No hypertension or cardiovascular/vascular disease
• No migraine or neurodegenerative disease
• No smoking or alcohol use
• No prior structured exercise training
• No musculoskeletal injury
• Willing to abstain from caffeine, alcohol, and strenuous exercise for 24 hours before testing

Exclusion Criteria:

• Hypertension or cardiovascular/vascular disease
• Migraine or neurodegenerative disease
• Current smoking or alcohol use
• Prior structured exercise training history
• Musculoskeletal injury precluding resistance or endurance exercise

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Strength-only training; Participants performed a supervised resistance training program three times weekly for 8 weeks: weighted calf raises (80% 1RM, 4x6), back squats (75% 1RM, 4x6), countermovement jumps (60-cm target height, 4x6), and weighted lunges (60% 1RM, 4x5), using a Smith machine.	Other: Strength-only training; Supervised resistance exercise comprising weighted calf raises, back squats, countermovement jumps, and weighted lunges, performed on a Smith machine three times weekly for 8 weeks.
Experimental: Concurrent training; Participants performed the identical resistance training program as the Strength-only arm, followed by 30-40 minutes of moderate-intensity treadmill running (46-64% VO2max) once heart rate had returned to 40% of maximum, three times weekly for 8 weeks (a strength-priority exercise sequence).	Other: Concurrent training; performed on a Smith machine three times weekly for 8 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
skin sympathetic nerve activity (aSKNA)	Average rectified voltage of skin sympathetic nerve activity recorded noninvasively via the neuECG method.	Baseline and 8 weeks
Change in one-repetition maximum (1RM) back squat		Baseline and 8 weeks
Change in countermovement jump (CMJ) height		Baseline and 8 weeks

Secondary Outcome Measures

Outcome Measure	Time Frame
Change in CMJ peak velocity	Baseline and 8 weeks
Change in CMJ peak power	Baseline and 8 weeks
Change in SKNA burst duration	Baseline and 8 weeks
Change in SKNA burst amplitude	Baseline and 8 weeks
Change in SKNA burst total area	Baseline and 8 weeks
Change in CMJ peak force	Baseline and 8 weeks

Collaborators and Investigators

• Sponsor: Beijing Sport University
• Collaborators: China institute of sport science

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2024
• Primary Completion (Actual): December 12, 2024
• Study Completion (Actual): December 13, 2024

Study Registration Dates

• First Submitted: June 22, 2026
• First Submitted That Met QC Criteria: June 25, 2026
• First Posted (Actual): July 2, 2026

Study Record Updates

• Last Update Posted (Actual): July 2, 2026
• Last Update Submitted That Met QC Criteria: June 25, 2026
• Last Verified: September 1, 2024

More Information

Terms related to this study

• Keywords: autonomic nervous system; resistance training; skin sympathetic nerve activity; concurrent training
• Other Study ID Numbers: BSU-2024224H

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data that underlie the results reported in this article will be made available upon reasonable request to the corresponding author.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No