The effect of an action-specific isokinetic task on the functional H/Q ratio

Sauret, Jérôme (2007) The effect of an action-specific isokinetic task on the functional H/Q ratio. Masters thesis, University of Gloucestershire.

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The aetiological factor for the occurrence of ACL injury is a failure of the stability systems during the performance of a decelerating manoeuvre. Deficient neuromuscular efficiency ,due to decreased joint angle, increased velocity and the presence of fatigue, has been suggested as potential ACL injury risk factor. The ratio of eccentric extension to concentric extension peak torques, commonly referred to as the functional ratio (Hamstring I Quadriceps) (FR), is a useful marker of reciprocal muscle symmetry. In the present study, the FR was calculated before and after an isokinetic "action-specific" fatigue protocol (50 eccentric Hamstring repetitions / 50 concentric Quadriceps repetitions). Finally, the Concentric Quadriceps and Eccentric Hamstring changes in torque production relationships were investigated. Those calculations use net torque values and as such fail to take co-activation issues into consideration. A pilot study examined the relative and absolute inter-day reliability of the measurements associated with an isokinetic eccentric Hamstring fatigue task. Healthy male volunteers (15) participated in the study (age 26 yrs ± 6 yrs, stature 183.3 cm± 6.8 cm, body mass 86.1 kg ± 11.6 kg). The participants were habituated and then performed the fatigue task twice, two weeks apart. Intraclass correlation coefficients and the repeatability coefficients associated with 95% LoA, suggested moderate to low reproducibility for the fatigue index but sufficient reliability for peak torque and work performed. The main study used two repeated measures ANOV A to observe effects and interactions between time (2) and joint angle- specific FR (2) and between time (2) and angular velocity-specific FR (3). 20 healthy males volunteers participated in the study (age 26 yrs ± 6 yrs, stature 183.1 cm± 6.8 cm, body mass 84.3 kg± 11.5 kg). The testing occurred during two sessions, two weeks apart, randomly allocated to test each muscle group separately. After a standardised warm-up the participants performed pre-fatigue task esting at three velocities, followed by the isokinetic fatigue task (50 eccentric Hamstring repetitions or 50 Quadriceps extensors repetitions) and post-fatigue testing at the same three velocities. It is accepted that the normal r

Item Type: Thesis (Masters)
Thesis Advisors:
Thesis AdvisorEmailURL
De Ste Croix,
Additional Information: A print copy of this thesis is available for reference use only.
Uncontrolled Keywords: Anterior Cruciate Ligament (ACL); Injury risk; Hamstring; Quadriceps; Isokinetic fatigue task; Neuromuscular efficiency
Related URLs:
Subjects: R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions: Schools and Research Institutes > School of Education and Applied Sciences
Depositing User: Susan Turner
Date Deposited: 25 Jan 2022 17:06
Last Modified: 31 Aug 2023 09:11

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