The influence of variable resistance moment arm on knee extensor performance
| Autor: | Bertrand Baron, T. Verstraete, Georges Dalleau, Chantal Verkindt, Pierre Leroyer, Bruno Bonazzi |
|---|---|
| Přispěvatelé: | Déterminants Interculturels de la Motricité et de la Performance Sportive (DIMPS), Université de La Réunion (UR) |
| Rok vydání: | 2010 |
| Předmět: |
Male
medicine.medical_specialty business.product_category Knee Joint Physical Therapy Sports Therapy and Rehabilitation Physical strength medicine.disease_cause moment arm Weight-bearing Pulley Weight-Bearing 03 medical and health sciences 0302 clinical medicine Physical medicine and rehabilitation Task Performance and Analysis [SDV.MHEP.PHY]Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO] medicine Humans Torque Knee Orthopedics and Sports Medicine [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph] Mathematics extension Resistance Training 030229 sport sciences Mechanism (engineering) Moment (mathematics) Arm Physical therapy medicine.symptom business 030217 neurology & neurosurgery Muscle contraction |
| Zdroj: | Journal of Sports Sciences Journal of Sports Sciences, Taylor & Francis, 2010, 28 (6), pp.657--665. ⟨10.1080/02640411003631976⟩ |
| ISSN: | 1466-447X 0264-0414 |
| DOI: | 10.1080/02640411003631976 |
| Popis: | International audience; To enhance muscular strength, resistance training machines with a cam, incorporating a variable resistance moment arm, are widely used. However, little information is available about the influence of the variable resistance moment arm on torque, velocity, and power during muscle contraction. To address this, a knee extensor machine was equipped with a cam or with a semi-circular pulley that imposed a variable or a constant resistance moment arm, respectively. Fourteen physically active men performed two full knee extensions against loads of 40-80 kg in both conditions. Participants developed significantly higher torque with the pulley than with the cam (P \textless 0.001). The relative differences between pulley and cam conditions across all loads ranged from 8.72% to 19.87% (P \textless 0.001). Average knee extension velocity was significantly higher in the cam condition than in the pulley condition. No differences were observed in average and peak power, except at 50 and 55 kg. Torque-velocity and power-velocity relationships were modified when the resistance moment arm was changed. In conclusion, whatever the link, namely cam or pulley, the participants produced similar power at each load. However, the torque-velocity and power-velocity relationships were different in the cam and pulley conditions. The results further suggest that the influence of the machine's mechanism on muscular performance has to be known when prescribing resistance exercises. |
| Databáze: | OpenAIRE |
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