Functional Performance, Healthy Older Adults, Muscle Power, Neuromuscular Function, Older Adults (65 Years and Older), Physiological Responses
Conditions
Keywords
Power Training, Older Adults, Aging, Muscle Power, Velocity Loss, Resistance Training, Neuromuscular Function, Functional Performance, Physiological Responses, Exercise Fatigue
Brief summary
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.
Interventions
BEHAVIORALPower Training at Different Fatigue Levels
Participants perform supervised power-training exercise on a pneumatic leg press. Each participant completes three exercise sessions, each separated by approximately one week. In each session, participants perform 4 sets of leg press exercise under different fatigue conditions: A) Exercise sets are terminated when movement velocity decreases by 10%. B) Exercise sets are terminated when movement velocity decreases by 30%. C) Exercise sets are terminated at 10% velocity loss, with total work matched to the 30% condition.
Sponsors
Hasselt University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
NONE
Intervention model description
Participants will complete three exercise sessions different by fatigue and volume levels, each separated by about one week. The order of the first two sessions will be randomized. These sessions involve two different exercise conditions with different levels of fatigue. The third session will always be performed last. This session is designed to match the total amount of exercise volume performed in one of the earlier sessions for each participant individually. Because this matching depends on the amount of exercise volume completed previously, the final session must occur after the first two sessions. This study design allows researchers to compare how different levels of fatigue affect participants' responses to exercise, while also examining the effects of exercise volume independently of fatigue.
Eligibility
Sex/Gender
ALL
Age
65 Years to 85 Years
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Maximum Voluntary Contraction (MVC) | Measurements will be taken before exercise (baseline), 5 minutes after each training session, and 24 hours after each session. | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Rate of Torque Development (RTD) | Measurements will be taken before exercise (baseline), 5 minutes after each training session, and 24 hours after each session. | 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). |
| Muscle Activity | 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) | 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. |
| Strength Training Data: Mean Movement Velocity | During each exercise session (mean values across the full session) (3 Sessions ; ~1 week apart) | Mean concentric movement velocity (meter per second (m/s)) recorded during each leg press (exercise) repetition using the Keiser A400 Leg Press. |
| Strength Training Data: Power | During each exercise session (mean value across the full session) (3 Sessions ; ~1 week apart) | Mean mechanical power (Watts (W)) produced during each leg press repetition recorded by the Keiser A400 Leg Press. |
| Strength Training Data: Total Number of Repetitions | During each exercise session (mean value across the full session) (3 Sessions ; ~1 week apart) | Total number of repetitions (count) completed during each exercise session on the leg press. |
| Muscle Oxygenation | 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) | 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. |
| Blood Lactate | Measurements will be taken at baseline and immediately post exercise session (3 sessions, 1 week apart) | Small blood sample will be taken to measure lactate, in millimoles per liter analysed through standard laboratory tests, including Enzyme-Linked Immunosorbent Assay (ELISA). |
| Blood Gas | Measurements will be taken at baseline and immediately post exercise session (3 sessions, 1 week apart). | 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). |
| Creatine Kinase (CK) | Measurements will be taken at Baseline and 24 hours after each exercise session. | 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). |
| Functional Performance: Five-Repetition Sit-to-Stand Test | Measurements will be taken at Baseline, immediate post exercise and 24 hours after each exercise session. | 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). |
| Functional Performance: Counter Movement Jump | Measurements will be taken at Baseline, immediate post exercise and 24 hours after each exercise session. | Countermovement Jump (CMJ): Participants jump vertically from a standing position. Jump height (cm), force (Nm), and power (W) are measured using KINVENT force plates. |
| Functional Performance: Stair Ascent test | Measurements will be taken at Baseline, immediate post exercise and 24 hours after each exercise session. | 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). |
| Functional Performance: 30-s Sit-to-Stand Test | Measurements will be taken at Baseline, immediate post exercise and 24 hours after each exercise session. | 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). |
| Perceived Exertion | Assessed after each exercise set during each exercise session (mean value across the full session) (3 Sessions ; ~1 week apart) | 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. |
| Delayed Onset Muscle Soreness (DOMS) | Ratings will be collected at baseline, 24 hours after exercise, and 48 hours after exercise using a remote survey. | 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. |
Countries
Belgium
Contacts
CONTACTMax Riesbeck, Master of Science
CONTACTEvelien Van Roie, PhD
PRINCIPAL_INVESTIGATOREvelien Van Roie, PhD
Hasselt University, Faculty of Rehabilitation Sciences
PRINCIPAL_INVESTIGATORBruno Tassignon, PhD
Hasselt University, Faculty of Rehabilitation Sciences
Outcome results
None listed