Acute Power Training Effects in Older Adults (APTE-OA)

Acute Neuromuscular and Physiological Responses to Different Velocity Loss Thresholds During Power Training in Older Adults

The goal of this clinical trial is to learn how older adults respond to power training when the level of fatigue during exercise is different. Power training means performing fast movements with moderate loads to improve strength, power and mobility.

The main questions the study aims to answer are:

• How does the level of fatigue during power training acutely affect strength, movement, and muscle function?
• How does it affect recovery, muscle soreness, and how hard the exercise feels?

Researchers will compare three power-training sessions with different fatigue levels to see which approach may be safest and most effective for older adults.

Participants will be healthy older adults aged 65 to 85 years. Each participant will complete three supervised exercise sessions on a leg press machine. The sessions will take place about one week apart.

During the study, participants will:

• Perform power training on a pneumatic leg press machine
• Complete strength and mobility tests before and after exercise
• Provide small blood samples to measure body responses to exercise
• Rate how hard the exercise feels
• Report muscle soreness for up to two days after exercise

The results may help researchers design safer and more effective power-training programs to improve strength, mobility, and recovery in older adults.

Study Overview

• Status: Recruiting
• Conditions: Physiological Responses; Functional Performance; Healthy Older Adults; Neuromuscular Function; Muscle Power; Older Adults (65 Years and Older)
• Intervention / Treatment: Behavioral: Power Training at Different Fatigue Levels

• Study Type: Interventional
• Enrollment (Estimated): 42
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Max Riesbeck, Master of Science; Phone Number: +32 11 26 84 93; Email: max.riesbeck@uhasselt.be
• Study Contact Backup: Name: Evelien Van Roie, PhD; Phone Number: +3211269062; Email: evelien.vanroie@uhasselt.be

Study Locations

• Belgium
  • Flanders
    • Diepenbeek, Flanders, Belgium, 3590
      • Recruiting
      • REVAL - Faculty of Rehabilitation Sciences
      • Contact: Faculteit Revalidatiewetenschappen; Phone Number: +32(0)11 26 93 11; Email: reval.rws@uhasselt.be

Participation Criteria

Eligibility Criteria

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

Description

Inclusion criteria:

Participants must:

• Be 65 to 85 years old.
• Be able to live independently and perform everyday activities without help.
• Not have regularly done resistance or strength training in the past year.
• Be able to understand study instructions and communicate in the study language.
• Have a recent statement from their treating physician confirming that their heart and blood vessels are healthy enough to safely take part in this study.

Exclusion criteria

Participants will not be eligible if they have any of the following:

• Unstable heart disease, neurological disease, acute infection, or fever.
• Use of non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, in the 5 days before the study.
• Use of whey protein, casein, or amino acid supplements in the month before the study.
• Acute or chronic injuries to the legs or lower body muscles.
• Any injury or condition that prevents safe leg extension exercises.
• Recent lower-limb joint replacement (less than 6 months ago).
• Dependence on walking aids.
• Current participation in another interventional trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low-Fatigue Power Training (10% velocity loss); Participants perform a single supervised session of power training on a pneumatic leg press, consisting of 4 sets. During the exercise, movement speed is continuously monitored. In this arm, the exercise set will be stopped when movement speed decreases by 10% compared with the fastest repetition, which corresponds to a low level of fatigue (small amount of repetitions).	Behavioral: Power Training at Different Fatigue Levels; Participants perform supervised power-training exercises on a pneumatic leg press. The sessions are designed to test different levels of fatigue: In one session, participants stop the exercise set when their movement speed drops by 10%.; In another session, they stop when their movement speed drops by 30%.; In a third session, participants perform the same total work as the 30% session, but stop at 10% velocity loss. Each session lasts a single training bout (4 sets), and is separated from the next session by one week. During and after each session, researchers measure immediate and post 24h responses to the training in neuromuscular function, physiological responses (e.g., blood markers, muscle oxygenation), functional performance, perceived effort, and muscle soreness. This intervention is different from other exercise studies because it focuses on how varying fatigue levels during power training affect immediate performance and recovery in healthy older adults.; Other Names: Power Training at Different Velocity Loss Thresholds; Power Training at Different Velocity-Based Training Doses
Experimental: Moderate Fatigue Power Training (30% velocity loss); Participants perform a single supervised session of power training on a pneumatic leg press, consisting of 4 sets. During the exercise, movement speed is continuously monitored. In this arm, the exercise set will be stopped when movement speed decreases by 30% compared with the fastest repetition, which corresponds to a moderate level of fatigue (more repetitions, performed closer to muscle failure).	Behavioral: Power Training at Different Fatigue Levels; Participants perform supervised power-training exercises on a pneumatic leg press. The sessions are designed to test different levels of fatigue: In one session, participants stop the exercise set when their movement speed drops by 10%.; In another session, they stop when their movement speed drops by 30%.; In a third session, participants perform the same total work as the 30% session, but stop at 10% velocity loss. Each session lasts a single training bout (4 sets), and is separated from the next session by one week. During and after each session, researchers measure immediate and post 24h responses to the training in neuromuscular function, physiological responses (e.g., blood markers, muscle oxygenation), functional performance, perceived effort, and muscle soreness. This intervention is different from other exercise studies because it focuses on how varying fatigue levels during power training affect immediate performance and recovery in healthy older adults.; Other Names: Power Training at Different Velocity Loss Thresholds; Power Training at Different Velocity-Based Training Doses
Experimental: Cluster-Set Power Training (10% Velocity Loss); Participants perform a single supervised session of power training on a pneumatic leg press. In this arm, the exercise is organized into 4 cluster sets. A cluster set consists of small groups of repetitions separated by short rest periods within the set. Participants will perform clusters of 3-4 repetitions with 20 seconds of rest between clusters. During the exercise, movement speed is continuously monitored. Each cluster will be performed within the range of 10% velocity loss compared with the fastest repetition, which corresponds to a low level of fatigue. Clusters will continue until the total number of repetitions matches the training volume (amount of total repetitions) reached in the 30% velocity loss condition. This design allows participants to complete a similar total training volume as in the moderate fatigue condition, while maintaining lower fatigue, enabling researchers to separate the effects of exercise volume from the effects of fatigue.	Behavioral: Power Training at Different Fatigue Levels; Participants perform supervised power-training exercises on a pneumatic leg press. The sessions are designed to test different levels of fatigue: In one session, participants stop the exercise set when their movement speed drops by 10%.; In another session, they stop when their movement speed drops by 30%.; In a third session, participants perform the same total work as the 30% session, but stop at 10% velocity loss. Each session lasts a single training bout (4 sets), and is separated from the next session by one week. During and after each session, researchers measure immediate and post 24h responses to the training in neuromuscular function, physiological responses (e.g., blood markers, muscle oxygenation), functional performance, perceived effort, and muscle soreness. This intervention is different from other exercise studies because it focuses on how varying fatigue levels during power training affect immediate performance and recovery in healthy older adults.; Other Names: Power Training at Different Velocity Loss Thresholds; Power Training at Different Velocity-Based Training Doses

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum Voluntary Contraction (MVC)	Maximum voluntary contraction (MVC) will be assessed to determine the maximum force-generating capacity of the leg extensors using an isokinetic dynamometer (Humac Norm). Simultaneously, muscle activity will be recorded using surface electromyography (EMG; Delsys EMG system). Primary outcome metric: Peak torque (Nm) obtained from three maximal isometric trials recorded on the dynamometer, combined with EMG amplitude (µV) to quantify muscle activation. Interpretation: Higher torque values indicate greater knee extensor strength. EMG amplitude reflects the level of muscle activation during maximal voluntary effort. Interpretation: Higher force values indicate greater leg muscle strength. EMG values indicate the level of muscle activation during the maximal effort.	Measurements will be taken before exercise (baseline), 5 minutes after each training session, and 24 hours after each session.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of Torque Development (RTD)	Rate of torque development (RTD) will be assessed to determine how quickly participants can generate torque with their leg extensors. This will be measured using an isokinetic dynamometer (Humac Norm), which records joint torque, alongside surface electromyography (EMG; Delsys EMG system), which measures muscle activation. This parameter provides insight into neuromuscular responses to different levels of power training-induced fatigue. Metric: Peak rate of torque development (Nm/s) calculated from three maximal trials, together with EMG amplitude (µV). RTD will be calculated as the slope of the torque-time curve over a specified time interval (e.g., 0-100ms, 100-200 ms).	Measurements will be taken before exercise (baseline), 5 minutes after each training session, and 24 hours after each session.
Muscle Activity	Muscle activity will be assessed by recording the electrical signals of the leg muscles during the leg press exercise using surface electromyography (sEMG; Delsys EMG system). This method enables quantification of muscle activation and fatigue-related changes in neuromuscular function. Surface electrodes will be placed on three key thigh muscles: the vastus lateralis, vastus medialis, and biceps femoris. Metric: EMG amplitude (µV), derived from the recorded electrical signals, representing the level of muscle activation during exercise.	Measurements will be taken before exercise (baseline), during exercise session (mean value across the full session), 5 minutes post exercise, and 24 hours post exercise (3 exercise sessions, 1 week apart)
Strength Training Data: Mean Movement Velocity	Mean concentric movement velocity (meter per second (m/s)) recorded during each leg press (exercise) repetition using the Keiser A400 Leg Press.	During each exercise session (mean values across the full session) (3 Sessions ; ~1 week apart)
Strength Training Data: Power	Mean mechanical power (Watts (W)) produced during each leg press repetition recorded by the Keiser A400 Leg Press.	During each exercise session (mean value across the full session) (3 Sessions ; ~1 week apart)
Strength Training Data: Total Number of Repetitions	Total number of repetitions (count) completed during each exercise session on the leg press.	During each exercise session (mean value across the full session) (3 Sessions ; ~1 week apart)
Muscle Oxygenation	Muscle oxygenation will be assessed to determine oxygen availability in the thigh muscle (vastus lateralis) during and after exercise using near-infrared spectroscopy (NIRS). In addition, a vascular occlusion test will be performed to evaluate muscle oxygen extraction and the recovery kinetics of oxygenation following transient blood flow restriction. Metric: Muscle oxygen saturation (%; e.g., SmO₂), as well as reoxygenation rate and amplitude following occlusion.	Baseline (pre-exercise), continuously during each exercise session, 5 minutes post-exercise, and 24 hours post-exercise (for each of the 3 sessions, 1 week apart)
Blood Lactate	Small blood sample will be taken to measure lactate, in millimoles per liter analysed through standard laboratory tests, including Enzyme-Linked Immunosorbent Assay (ELISA).	Measurements will be taken at baseline and immediately post exercise session (3 sessions, 1 week apart)
Blood Gas	A Small blood sample will be taken to measure blood gas levels (blood oxygen/carbon dioxide levels) using standard laboratory tests, including Enzyme-Linked Immunosorbent Assay (ELISA).	Measurements will be taken at baseline and immediately post exercise session (3 sessions, 1 week apart).
Creatine Kinase (CK)	Small blood samples will be taken to measure creatine kinase (CK), an enzyme that increases in the blood when muscles are damaged or stressed. Metric: CK concentration in units per liter (U/L).	Measurements will be taken at Baseline and 24 hours after each exercise session.
Functional Performance: Five-Repetition Sit-to-Stand Test	Five-Repetition Sit-to-Stand (5xSTS) test: Participants stand up from a chair repeatedly. An inertial measurement unit (DynaPort MoveTest, McRoberts, The Hague, NL) measures speed (meters per second (m/s)), movement duration (s) , and power (W).	Measurements will be taken at Baseline, immediate post exercise and 24 hours after each exercise session.
Functional Performance: Counter Movement Jump	Countermovement Jump (CMJ): Participants jump vertically from a standing position. Jump height (cm), force (Nm), and power (W) are measured using KINVENT force plates.	Measurements will be taken at Baseline, immediate post exercise and 24 hours after each exercise session.
Functional Performance: Stair Ascent test	Stair Ascent Test (SA): Participants climb a set of stairs while wearing an inertial measurement unit (DynaPort MoveTest, McRoberts, The Hague, NL), which measures speed (m/s), movement duration (s), distance (cm), and power (W).	Measurements will be taken at Baseline, immediate post exercise and 24 hours after each exercise session.
Functional Performance: 30-s Sit-to-Stand Test	30-Second Sit-to-Stand (30sSTS) Tests: Participants stand up from a chair repeatedly. An inertial measurement unit (DynaPort MoveTest, McRoberts, The Hague, NL) measures speed (m/s), movement duration (s), and power (W).	Measurements will be taken at Baseline, immediate post exercise and 24 hours after each exercise session.
Perceived Exertion	Perceived exertion will be assessed using the OMNI Resistance Exercise Scale (OMNI-RES). Participants will rate their level of effort after each exercise set during the leg press sessions. The scale ranges from 1 (no exertion at all) to 10 (maximum effort), with higher scores indicating greater perceived exertion.	Assessed after each exercise set during each exercise session (mean value across the full session) (3 Sessions ; ~1 week apart)
Delayed Onset Muscle Soreness (DOMS)	Delayed onset of muscle soreness (DOMS) will be assessed using a Visual Analog Scale (VAS). Participants will rate perceived soreness in the leg muscles on a scale from 0 (no soreness) to 10 (worst possible soreness), with higher scores indicating greater muscle soreness.	Ratings will be collected at baseline, 24 hours after exercise, and 48 hours after exercise using a remote survey.

Collaborators and Investigators

• Sponsor: Hasselt University
• Investigators: Principal Investigator: Evelien Van Roie, PhD, Hasselt University, Faculty of Rehabilitation Sciences; Principal Investigator: Bruno Tassignon, PhD, Hasselt University, Faculty of Rehabilitation Sciences

Study record dates

Study Major Dates

• Study Start (Estimated): April 20, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 1, 2027

Study Registration Dates

• First Submitted: March 25, 2026
• First Submitted That Met QC Criteria: April 3, 2026
• First Posted (Actual): April 13, 2026

Study Record Updates

• Last Update Posted (Actual): April 13, 2026
• Last Update Submitted That Met QC Criteria: April 3, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Older Adults; Aging; Resistance Training; Muscle Power; Functional Performance; Power Training; Neuromuscular Function; Physiological Responses; Exercise Fatigue; Velocity Loss
• Other Study ID Numbers: B1152025000035; BOF25OWB22 (Other Grant/Funding Number: BOF)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Pseudonymazed participant data, including study measurements and outcomes, along with relevant supporting documents (e.g., study protocol, statistical analysis plan). Data will be shared via a Data Transfer Agreement (DTA). Access may be provided through a secure repository such as FAIRVault.
• IPD Sharing Time Frame: Beginning upon publication until 5 years after the publication of results.

IPD Sharing Access Criteria

Only qualified researchers affiliated with recognized academic or research institutions will be eligible. Researchers must submit a formal request describing the purpose and planned analyses. The research proposal must relate to legitimate scientific questions consistent with the original study aims. The proposed statistical methods must be clearly described.

Researchers submit a data access request through the study's contact point or the FAIRVault platform. Once approved, they will sign a Data Transfer Agreement (DTA) before receiving access to the data. All requests will be reviewed by the study team or designated independent reviewers to ensure the research is appropriate, the data will be handled responsibly, and privacy protections are met.

• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

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