Acute Effects of Variable-Resistance and Free-Weight Bench Pull Exercise in Resistance-Trained Men
Acute Comparison of High-Load Variable-Resistance and Free-Weight Bench Pulls: A Randomized Crossover Study of Exercise Responses and Residual Effects
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.
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Status
Condições
Intervenção / Tratamento
Descrição detalhada
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.
Tipo de estudo
Inscrição (Real)
Estágio
- Não aplicável
Contactos e Locais
Locais de estudo
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Tianjin Municipality
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Tianjin, Tianjin Municipality, China, 510760
- Tianjin University of Sport
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Critérios de participação
Critérios de elegibilidade
Idades elegíveis para estudo
Aceita Voluntários Saudáveis
Gêneros Elegíveis para o Estudo
Descrição
Inclusion Criteria:
- 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.
Exclusion Criteria:
- 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.
Plano de estudo
Como o estudo é projetado?
Detalhes do projeto
- Finalidade Principal: Ciência básica
- Alocação: Randomizado
- Modelo Intervencional: Atribuição cruzada
- Mascaramento: Nenhum (rótulo aberto)
Armas e Intervenções
Grupo de Participantes / Braço |
Intervenção / Tratamento |
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Experimental: 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. |
Participants performed one set of three bench-pull repetitions at approximately 85% of their free-weight one-repetition maximum. External resistance was provided by a combination of barbell load and chains, with the chains contributing approximately 20% of the effective mean total load. Participants were instructed to perform the concentric phase with maximal intended velocity. After the high-load bench pull, participants rested for 3 minutes and then completed three standardized free-weight bench-pull sets at approximately 75% of one-repetition maximum, with 3-minute rest intervals between sets. Each subsequent set was terminated when mean repetition velocity fell below 0.65 m·s-¹ or when the prescribed range of motion could not be completed. Participants performed one set of three bench-pull repetitions at approximately 85% of their free-weight one-repetition maximum, with the external resistance provided entirely by the barbell. Participants were instructed to perform the concentric phase with maximal intended velocity. After the high-load bench pull, participants rested for 3 minutes and then completed three standardized free-weight bench-pull sets at approximately 75% of one-repetition maximum, with 3-minute rest intervals between sets. Each subsequent set was terminated when mean repetition velocity fell below 0.65 m·s-¹ or when the prescribed range of motion could not be completed. |
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Experimental: 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. |
Participants performed one set of three bench-pull repetitions at approximately 85% of their free-weight one-repetition maximum. External resistance was provided by a combination of barbell load and chains, with the chains contributing approximately 20% of the effective mean total load. Participants were instructed to perform the concentric phase with maximal intended velocity. After the high-load bench pull, participants rested for 3 minutes and then completed three standardized free-weight bench-pull sets at approximately 75% of one-repetition maximum, with 3-minute rest intervals between sets. Each subsequent set was terminated when mean repetition velocity fell below 0.65 m·s-¹ or when the prescribed range of motion could not be completed. Participants performed one set of three bench-pull repetitions at approximately 85% of their free-weight one-repetition maximum, with the external resistance provided entirely by the barbell. Participants were instructed to perform the concentric phase with maximal intended velocity. After the high-load bench pull, participants rested for 3 minutes and then completed three standardized free-weight bench-pull sets at approximately 75% of one-repetition maximum, with 3-minute rest intervals between sets. Each subsequent set was terminated when mean repetition velocity fell below 0.65 m·s-¹ or when the prescribed range of motion could not be completed. |
O que o estudo está medindo?
Medidas de resultados primários
Medida de resultado |
Descrição da medida |
Prazo |
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Average Mean and Peak Velocity During the High-Load Bench Pull
Prazo: Day 1 and Day 4, during the high-load bench-pull set
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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). |
Day 1 and Day 4, during the high-load bench-pull set
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Normalized Surface Electromyography Amplitude During the High-Load Bench Pull
Prazo: Day 1 and Day 4, during the high-load bench-pull set
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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. |
Day 1 and Day 4, during the high-load bench-pull set
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Number of Valid Repetitions Completed During Subsequent Free-Weight Bench-Pull Sets
Prazo: Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
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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. |
Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
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Movement Velocity During Subsequent Free-Weight Bench-Pull Sets
Prazo: Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
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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. |
Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
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Normalized Surface Electromyography Amplitude During Subsequent Free-Weight Bench-Pull Sets
Prazo: Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
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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. |
Day 1 and Day 4, beginning 3 minutes after the high-load bench-pull set
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- TJUS 2025-117
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