Interference of Endurance Training on Strength Development and Neuromuscular Adaptations

This study aims to find out if performing combined strength and endurance exercise in the same program (called concurrent training-CT) leads to similar long-term improvements in neuromuscular function as doing each type of exercise separately. The main questions it seeks to answer are:

Does performing CT result in similar improvements in strength and power as doing just strength training? Does performing CT result in similar improvements in cardiorespiratory fitness as doing just endurance training? Are neuromuscular adaptations similar between CT and just strength training? Researchers will compare the results between three groups: the CT group, the endurance training group (E), and the strength training group (S) to answer these questions.

Study Overview

• Status: Active, not recruiting
• Conditions: Exercise
• Intervention / Treatment: Behavioral: Endurance Exercise; Behavioral: Strength Exercise; Behavioral: Concurrent Exercise

Detailed Description

This study looks at how different types of exercise affect neuromuscular and cardiorespiratory improvements over time. It aims to see how combining strength and endurance training (concurrent training - CT) affects neuromuscular and cardiorespiratory adaptations compared to doing just strength or endurance training. Participants who regularly do both types of exercise will be split into three groups: Concurrent training (CT), endurance training (E), or strength training (S) and will be involved in 11 weeks of supervised training, three days a week:

Endurance training involves 30 minutes of continuous running, three days a week, at an intensity corresponding to the heavy domain (between the first and second ventilatory threshold) Strength training includes weightlifting three days a week, focusing on building both strength and power.

Concurrent training incorporates both strength and endurance exercises in the same session, three days a week, with strength training being executed prior to endurance training.

Researchers will collect data at three time-points during the 11 weeks: before starting the program (Baseline), at the end of week 5 (Week 5), and at the end of the program (Week 11). Measurements include lower-body strength and power, aerobic capacity, nerve evoked responses, and muscle structure if the quadriceps femoris.

Researchers will then compare the CT, E, and S groups at each measurement point to see which type of training elicited the best adaptations for the different neuromuscular and cardiorespiratory outcomes.

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

Contacts and Locations

Study Locations

• Portugal
  • Cruz Quebrada - Dafundo
    • Lisboa, Cruz Quebrada - Dafundo, Portugal, 1499-002
      • Faculdade de Motricidade Humana - Universidade de Lisboa

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Active training status (strength and endurance (running) exercise at least 2 times per week over the last three months prior to inclusion in the study)

Exclusion Criteria:

• Active smoking status
• Orthopedic injuries
• On medication
• Known cardiovascular or respiratory disease

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Endurance	Behavioral: Endurance Exercise; 30 minutes of running at an intensity corresponding to the heavy-domain (between the first and second ventilatory thresholds)
Experimental: Strength	Behavioral: Strength Exercise; Combination of strength and power exercises Weeks 1-5 focus on building maximal strength Weeks 6-11 focus on maintaining maximal strength and improve muscle power
Experimental: Concurrent	Behavioral: Concurrent Exercise; Combining both strength and endurance training programs, with strength preceding endurance, incorporating a 20-min rest period between each modality

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Surface EMG	Using surface electromyography (EMG), the muscle activation of the plantarflexors muscles will me assessed, as well as the quadriceps femoris during the leg press and back squat exercise	Baseline, Week 5, Week 11
H-reflex excitability	Using percutaneous electrostimulation of the tibial nerve, spinal reflex excitability will be explored by assessing H-reflex evoked responses	Baseline, Week 5, Week 11
V-wave	Using percutaneous electrostimulation of the tibial nerve, neural drive to the active muscle will be assessed by measuring V-wave amplitudes	Baseline, Week 5, Week 11
Maximal Isometric Strength	Maximal voluntary isometric strength of the plantarflexors and leg press exercise in Newtons	Baseline, Week 5, Week 11
Maximal Dynamic Strength	Maximal dynamic strength on the back squat exercise in kilograms lifted	Baseline, Week 5, Week 11
Lower Body Muscle Power	Lower body muscle power in watts will be assessed during countermovement jumps	Baseline, Week 5, Week 11
Muscle fascicle length	Fascicle length of the vastus lateralis muscles in centimeters	Baseline, Week 5, Week 11
Muscle fascicle pennation angle	Pennation angle of the vastus laterais fascicles, in degrees	Baseline, Week 5, Week 11
Muscle thickenss	Muscle thickenss of the vastus lateralis, in centimeters	Baseline, Week 5, Week 11

Collaborators and Investigators

• Sponsor: University of Lisbon
• Collaborators: Fundação para a Ciência e a Tecnologia

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2022
• Primary Completion (Actual): July 30, 2024
• Study Completion (Estimated): July 30, 2025

Study Registration Dates

• First Submitted: April 8, 2024
• First Submitted That Met QC Criteria: April 19, 2024
• First Posted (Actual): April 22, 2024

Study Record Updates

• Last Update Posted (Actual): December 3, 2024
• Last Update Submitted That Met QC Criteria: November 27, 2024
• Last Verified: November 1, 2024

More Information

Terms related to this study

• Keywords: Concurrent training; Strength; Endurance; Interference effect; Neuromuscular adaptations
• Other Study ID Numbers: 6/2021

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No