Acute Comparison of High-Load Variable-Resistance and Free-Weight Bench Pulls: A Randomized Crossover Study of Exercise Responses and Residual Effects
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 15
- 试验地点
- 1
- 主要终点
- Average Mean and Peak Velocity During the High-Load Bench Pull
研究概览
简要总结
This study used a randomized, counterbalanced crossover design to compare high-load chain-based variable-resistance (VR) and free-weight (FW) bench pulls. Resistance-trained men completed two experimental sessions separated by 72 hours, with the order of the VR and FW conditions randomized.
Before each experimental condition, participants completed a standardized general and bench pull-specific warm-up followed by a 10-minute rest period. In each session, participants performed one set of three bench pull repetitions at approximately 85% of their free-weight one-repetition maximum (1RM). In the VR condition, the external resistance was provided by a combination of barbell load and chains, with chains contributing approximately 20% of the effective mean total load. In the FW condition, the external resistance was provided entirely by the barbell.
Following the high-load bench pull, participants rested for 3 minutes and then completed three standardized sets of free-weight bench pulls at approximately 75% 1RM, with 3-minute rest intervals between sets. Each subsequent set was terminated when the mean velocity of a repetition fell below 0.65 m·s-¹ or when the participant was unable to complete the prescribed range of motion.
Direct exercise responses during the high-load bench pulls were assessed using movement velocity and surface electromyography. Residual effects during the subsequent free-weight sets were assessed using repetition count, movement velocity, and surface electromyography. The crossover design allowed each participant to complete both loading conditions and therefore serve as his own control.
详细描述
This study used a randomized, counterbalanced crossover design to compare the acute effects of high-load chain-based variable resistance (VR) and free-weight (FW) resistance during the bench pull exercise. Resistance-trained men completed both experimental conditions in separate sessions, with the order of conditions randomized and the sessions separated by 72 hours.
Before each experimental condition, participants completed a standardized general warm-up and a bench pull-specific warm-up, followed by a 10-minute rest period. In each session, participants performed one set of three bench pull repetitions at approximately 85% of their free-weight one-repetition maximum (1RM). In the VR condition, external resistance was provided by a combination of barbell load and chains, with chains contributing approximately 20% of the effective mean total load. In the FW condition, external resistance was provided entirely by the barbell.
After the high-load bench pull, participants rested for 3 minutes and then completed three standardized sets of free-weight bench pulls at approximately 75% 1RM, with 3-minute rest intervals between sets. Each subsequent set was terminated when the mean velocity of a repetition fell below 0.65 m·s-¹ or when the participant was unable to complete the prescribed range of motion.
Movement velocity and surface electromyography were recorded during the high-load bench pulls to evaluate direct exercise responses. During the subsequent free-weight sets, repetition count, movement velocity, and surface electromyography were assessed to evaluate residual effects of the preceding high-load condition. The crossover design allowed each participant to complete both loading conditions and therefore serve as his own control.
研究设计
- 研究类型
- 干预性
- 分配方式
- 随机
- 干预模型
- 交叉
- 主要目的
- 基础科学
- 盲法
- 开放（无盲法）
入排标准
- 年龄范围
- 18 Years 至 30 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- Male adults aged 18-30 years.
- At least 1 year of resistance-training experience.
- Proficiency in the bench-pull technique.
- Bench-pull one-repetition maximum (1RM) of at least 1.0 × body mass.
- No current use of medications that could affect neuromuscular performance.
- No history of cardiovascular, neurological, or metabolic disease.
- No upper-body musculoskeletal injury within the previous year.
- Willing and able to provide written informed consent.
排除标准
- Consumption of caffeine within 12 hours before testing.
- Consumption of alcohol within 24 hours before testing.
- Performance of any upper-body pulling exercise within 48 hours before testing.
研究组 & 干预措施
Variable Resistance, Then Free Weight
Participants completed the high-load variable-resistance bench-pull condition during the first experimental session and the high-load free-weight bench-pull condition during the second experimental session. The two sessions were separated by 72 hours. In each session, the high-load bench pull was followed after 3 minutes by three standardized free-weight bench-pull sets at approximately 75% of one-repetition maximum.
干预措施: High-Load Variable-Resistance Bench Pull (Other)
Variable Resistance, Then Free Weight
Participants completed the high-load variable-resistance bench-pull condition during the first experimental session and the high-load free-weight bench-pull condition during the second experimental session. The two sessions were separated by 72 hours. In each session, the high-load bench pull was followed after 3 minutes by three standardized free-weight bench-pull sets at approximately 75% of one-repetition maximum.
干预措施: High-Load Free-Weight Bench Pull (Other)
Free Weight, Then Variable Resistance
Participants completed the high-load free-weight bench-pull condition during the first experimental session and the high-load variable-resistance bench-pull condition during the second experimental session. The two sessions were separated by 72 hours. In each session, the high-load bench pull was followed after 3 minutes by three standardized free-weight bench-pull sets at approximately 75% of one-repetition maximum.
干预措施: High-Load Variable-Resistance Bench Pull (Other)
Free Weight, Then Variable Resistance
Participants completed the high-load free-weight bench-pull condition during the first experimental session and the high-load variable-resistance bench-pull condition during the second experimental session. The two sessions were separated by 72 hours. In each session, the high-load bench pull was followed after 3 minutes by three standardized free-weight bench-pull sets at approximately 75% of one-repetition maximum.
干预措施: High-Load Free-Weight Bench Pull (Other)
结局指标
主要结局
Average Mean and Peak Velocity During the High-Load Bench Pull
时间窗: Day 1 and Day 4, during the high-load bench-pull set
Movement velocity was measured using a linear position transducer sampling at 100 Hz. Mean velocity and peak velocity were obtained for each of the three repetitions performed during the high-load bench-pull set. For each loading condition, average mean velocity and average peak velocity were calculated by averaging the corresponding values across the three repetitions. Velocity was expressed in meters per second (m·s-¹).
Normalized Surface Electromyography Amplitude During the High-Load Bench Pull
时间窗: Day 1 and Day 4, during the high-load bench-pull set
Surface electromyography was recorded from the right latissimus dorsi, teres major, posterior deltoid, and middle trapezius. Root mean square amplitudes were normalized to the maximal root mean square amplitude obtained during maximal voluntary isometric contraction testing and expressed as a percentage of maximal voluntary isometric contraction (%MVIC). Mean and peak electromyography amplitudes were obtained for each repetition and averaged separately across the three high-load repetitions.
Number of Valid Repetitions Completed During Subsequent Free-Weight Bench-Pull Sets
时间窗: Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
Participants completed three subsequent free-weight bench-pull sets at approximately 75% of one-repetition maximum. Each set was terminated when the mean velocity of a repetition fell below 0.65 m·s-¹ or when the participant was unable to complete the prescribed range of motion. The number of valid repetitions completed in each of the three sets was recorded.
Movement Velocity During Subsequent Free-Weight Bench-Pull Sets
时间窗: Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
Mean and peak velocity were measured during each of the three subsequent free-weight bench-pull sets. For the repetition-matched analysis, velocity outcomes included average velocity, fastest-repetition velocity, matched-final velocity, velocity maintenance, and velocity decline. Repetition matching was performed separately for each participant and corresponding set using the smaller number of valid repetitions completed across the two experimental conditions.
Normalized Surface Electromyography Amplitude During Subsequent Free-Weight Bench-Pull Sets
时间窗: Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
Mean and peak surface electromyography amplitudes were assessed for the right latissimus dorsi, teres major, posterior deltoid, and middle trapezius during each of the three subsequent free-weight bench-pull sets. Electromyography amplitudes were normalized to maximal voluntary isometric contraction and expressed as %MVIC. For the repetition-matched analysis, mean and peak amplitudes were averaged separately across all included repetitions within each set.
次要结局
未报告次要终点
研究者
Zongwei Chen
Principal Investigator
South China Normal University
研究点 (1)
标识符
- NCT 编号
- NCT07846774
- 其他研究编号
- TJUS 2025-117
日期
- 首次提交
- (13天前)
- 首次发布
- (昨天)
- 主要完成日期
- (3个月前)
- 研究完成日期
- (29天前)
- 最近核实
- (29天前)
- 最近更新
- (昨天)
监管与共享
- FDA 监管药物
- 否
- FDA 监管器械
- 否
- 是否有结果
- 否