Concentric vs Eccentric Exercise in Blood Flow Restriction Training

Condition(s) studied

Investigational drug(s) / intervention(s)

concentric group: Participants assigned to this group will perform blood flow restriction (BFR) training combined with concentric elbow flexion exercises using the dominant upper extremity. Training will be performed three times per week for four weeks (12 sessions). Exercises will be performed at 20-30% of one-repetition maximum (1RM) using a pneumatic cuff applied to the proximal upper arm. The cuff pressure will be set at 50% of the individual's arterial occlusion pressure. Each session will consist of four sets (30-15-15-15 repetitions) with 30-second rest intervals between sets.

eccentric group: Participants assigned to this group will perform blood flow restriction (BFR) training combined with eccentric elbow flexion exercises using the dominant upper extremity. Training will be performed three times per week for four weeks (12 sessions). Exercises will be performed at 20-30% of one-repetition maximum (1RM) using a pneumatic cuff applied to the proximal upper arm. The cuff pressure will be set at 50% of the individual's arterial occlusion pressure. Each session will consist of four sets (30-15-15-15 repetitions) with 30-second rest intervals between sets.

Study summary

This randomized controlled trial will investigate the effects of blood flow restriction (BFR) training combined with concentric or eccentric exercise on upper extremity reaction speed, muscle strength, and muscle oxygenation in healthy adults aged 18-35 years. A total of 34 participants will be randomly allocated to either a BFR combined with concentric exercise group (n=17) or a BFR combined with eccentric exercise group (n=17).

Before the intervention, maximal muscle strength will be determined using a one-repetition maximum (1RM) test for the dominant elbow flexor muscles. Upper extremity reaction speed will be assessed using the Nelson Hand Reaction Test. Biceps brachii muscle strength will be measured with a digital dynamometer, and muscle oxygenation will be evaluated using a near-infrared spectroscopy (NIRS) device. All outcome measures will be obtained 72 hours before the intervention and repeated 72 hours after completion of the training program by the same investigator.

The findings of this study will contribute to understanding whether concentric or eccentric exercise combined with BFR training provides greater improvements in upper extremity reaction speed, muscle strength, and muscle oxygenation in healthy individuals.

Eligibility

Primary outcome measure(s)

• Upper Extremity Reaction Time — Baseline (72 hours before the intervention) and 72 hours after completion of the 4-week intervention.
  Upper extremity reaction time will be assessed using the Nelson Hand Reaction Test. Participants will complete five trials, the highest and lowest values will be discarded, and the mean of the remaining three trials will be used for analysis. Reaction time will be calculated from the ruler drop distance using the standard equation.
• Biceps Brachii Muscle Strength — Baseline (72 hours before the intervention) and 72 hours after completion of the 4-week intervention.
  Biceps brachii muscle strength will be measured using an ActivForce 2 digital dynamometer. Three maximal isometric contractions will be performed with 30-second rest intervals, and the highest value will be used for analysis.
• Hand Grip Strength — Baseline (72 hours before the intervention) and 72 hours after completion of the 4-week intervention.
  Hand grip strength will be measured using a hydraulic hand dynamometer. Participants will perform three maximal contractions with 30-second rest intervals, and the highest value will be recorded for analysis.
• Pinch Strength — Baseline (72 hours before the intervention) and 72 hours after completion of the 4-week intervention.
  Pinch strength will be assessed using a pinch dynamometer. Three maximal trials will be performed with 30-second rest intervals, and the highest value will be used for analysis.
• One-Repetition Maximum — Baseline (72 hours before the intervention) and 72 hours after completion of the 4-week intervention.
  Maximum muscle strength of the elbow flexors will be estimated using the Epley equation based on the maximum number of repetitions completed with a fixed load (2 kg for females and 5 kg for males).
• Muscle Oxygen Saturation — Baseline (72 hours before the intervention) and 72 hours after completion of the 4-week intervention.
  Muscle oxygen saturation (SmO₂) of the biceps brachii will be measured using a MOXY near-infrared spectroscopy (NIRS) device. Baseline SmO₂ will be recorded before the 1RM test, continuous SmO₂ values will be monitored throughout the test, and recovery values will be recorded for 2-3 minutes after the test.

Trial sites (1)

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