Preserving functional ability is crucial for healthy aging. Unfortunately, age-related decreases in muscle power often lead to declines in functional ability. As power is the product of force and velocity, decreases in power can originate from changes in muscle force, contraction velocity, or both, varying between individuals. The primary method to prevent functional disability is power-based resistance training. Although training interventions are effective for most older adults, they do not induce substantial improvements in a subset of the population. These inconsistent outcomes may arise from neglecting the observed differences in the force-velocity (F-v) profiles between individuals. Therefore, this study provides a novel approach to resistance exercise, in which exercise dose is tailored according to the individual's F-v profile. The effectiveness of the tailored method will be assessed in a randomized control trial, comparing the effects of an individualized and a non-individualized 12-week training intervention on muscle power parameters and functional ability.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
80
2x/week, 35-45 min sessions, on leg press machine
KU Leuven - Department of Movement Sciences
Leuven, Vlaams-Brabant, Belgium
Maximal force (F0)
Unilateral (dominant leg) maximal force production (N) on the pneumatic leg press device (Leg Press Air 400, Keiser, USA). The test protocol consists of 2 sets of 1 repetition with increasing loads (5-10 kg increments), starting at 20% of body mass. When the participants fail to lift a certain load, the load will be decreased by 2.5-5 kg until their one repetition maximum (1-RM) is reached. The duration of the recovery time between sets will be based on the mean velocity in the preceding repetition, with longer rest periods after high-load, low-velocity attempts. Mean velocity of the best trial per load is used to estimate the individual F-v relationship through a linear equation. This F-v relationship will be used to examine the exercise-induced changes in maximal force.
Time frame: Change from baseline in maximal force at 12 weeks
Maximal velocity (V0)
Unilateral (dominant leg) maximal velocity production (m/s) on the pneumatic leg press device (Leg Press Air 400, Keiser, USA). The test protocol consists of 2 sets of 1 repetition with increasing loads (5-10 kg increments), starting at 20% of body mass. When the participants fail to lift a certain load, the load will be decreased by 2.5-5 kg until their one repetition maximum (1-RM) is reached. The duration of the recovery time between sets will be based on the mean velocity in the preceding repetition, with longer rest periods after high-load, low-velocity attempts. Mean velocity of the best trial per load is used to estimate the individual F-v relationship through a linear equation. This F-v relationship will be used to examine the exercise-induced changes in maximal velocity.
Time frame: Change from baseline in maximal velocity at 12 weeks
Force-velocity slope
Unilateral (dominant leg) force-velocity (F-v) slope on the pneumatic leg press device (Leg Press Air 400, Keiser, USA). F-v slope = force (N) as a function of velocity (m/s). The test protocol consists of 2 sets of 1 repetition with increasing loads (5-10 kg increments), starting at 20% of body mass. When the participants fail to lift a certain load, the load will be decreased by 2.5-5 kg until their one repetition maximum (1-RM) is reached. The duration of the recovery time between sets will be based on the mean velocity in the preceding repetition, with longer rest periods after high-load, low-velocity attempts. Mean velocity of the best trial per load is used to estimate the individual F-v relationship through a linear equation. This F-v relationship will be used to examine the exercise-induced changes in slope.
Time frame: Change from baseline in F-v slope at 12 weeks
Maximal power (P0)
Unilateral (dominant leg) maximal power production (Watt) on the pneumatic leg press device (Leg Press Air 400, Keiser, USA). The test protocol consists of 2 sets of 1 repetition with increasing loads (5-10 kg increments), starting at 20% of body mass. When the participants fail to lift a certain load, the load will be decreased by 2.5-5 kg until their one repetition maximum (1-RM) is reached. The duration of the recovery time between sets will be based on the mean velocity in the preceding repetition, with longer rest periods after high-load, low-velocity attempts. Mean velocity of the best trial per load is used to estimate the individual F-v relationship through a linear equation. This F-v relationship will be used to examine the exercise-induced changes in maximal power.
Time frame: Change from baseline in maximal power at 12 weeks
Force at maximal power
Unilateral (dominant leg) force at maximal power production (N) on the pneumatic leg press device (Leg Press Air 400, Keiser, USA). The test protocol consists of 2 sets of 1 repetition with increasing loads (5-10 kg increments), starting at 20% of body mass. When the participants fail to lift a certain load, the load will be decreased by 2.5-5 kg until their one repetition maximum (1-RM) is reached. The duration of the recovery time between sets will be based on the mean velocity in the preceding repetition, with longer rest periods after high-load, low-velocity attempts. Mean velocity of the best trial per load is used to estimate the individual F-v relationship through a linear equation. This F-v relationship will be used to examine the exercise-induced changes in force at maximal power.
Time frame: Change from baseline in force at maximal power at 12 weeks
Velocity at maximal power
Unilateral (dominant leg) velocity at maximal power production (m/s) on the pneumatic leg press device (Leg Press Air 400, Keiser, USA). The test protocol consists of 2 sets of 1 repetition with increasing loads (5-10 kg increments), starting at 20% of body mass. When the participants fail to lift a certain load, the load will be decreased by 2.5-5 kg until their one repetition maximum (1-RM) is reached. The duration of the recovery time between sets will be based on the mean velocity in the preceding repetition, with longer rest periods after high-load, low-velocity attempts. Mean velocity of the best trial per load is used to estimate the individual F-v relationship through a linear equation. This F-v relationship will be used to examine the exercise-induced changes in velocity at maximal power.
Time frame: Change from baseline in velocity at maximal power at 12 weeks
Exercise adherence
Number of sessions attended as a percentage of total sessions planned
Time frame: Total adherence over 12-week period
Short Physical Performance Battery (SPPB) score
Total score on the SPPB (min 0, max 12, higher scores indicate better performance)
Time frame: Change from baseline in SPPB test score at 12 weeks
Gait speed
The average speed (m/s) to walk 10m as fast as possible
Time frame: Change from baseline in gait speed at 12 weeks
Countermovement jump height
The jump height (cm) in a countermovement jump
Time frame: Change from baseline in countermovement jump height at 12 weeks
Timed up and go
The time (s) needed to stand up from a chair, walk 3 m, turn, walk back and sit down again (as fast as possible)
Time frame: Change from baseline in timed up and go time at 12 weeks
5-repetition sit-to-stand time
The time (s) needed to perform 5 sit-to-stand transitions
Time frame: Change from baseline in sit-to-stand performance at 12 weeks
5-repetition sit-to-stand power
The power (watt) needed to perform 5 sit-to-stand transitions
Time frame: Change from baseline in sit-to-stand performance at 12 weeks
Stair ascent time
The time (s) needed to ascend a flight of stairs
Time frame: Change from baseline in stair climbing performance at 12 weeks
Stair ascent power
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The power (Watt) needed to ascend a flight of stairs
Time frame: Change from baseline in stair climbing performance at 12 weeks