Journal of Sports Science and Medicine
Journal of Sports Science and Medicine
ISSN: 1303 - 2968   
Ios-APP Journal of Sports Science and Medicine
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©Journal of Sports Science and Medicine (2012) 11, 418 - 422

Research article
Rapid Hamstrings/Quadriceps Strength Capacity in Professional Soccer Players with Different Conventional Isokinetic Muscle Strength Ratios
Camila C. Greco, Wendell L. Da Silva, Sérgio R.A. Camarda, Benedito S. Denadai 
Author Information
Human Performance Laboratory, UNESP, Rio Claro, SP, Brazil

Benedito S. Denadai
✉ Human Performance Laboratory, UNESP, Av. 24A, 1515, Bela Vista, CEP 13506-900, Rio Claro, SP, Brazil
Email: bdenadai@rc.unesp.br
Publish Date
Received: 16-04-2012
Accepted: 17-05-2012
Published (online): 01-09-2012
 
 
ABSTRACT

Muscle strength imbalance can be an important factor in hamstrings muscle strain. A hamstrings/quadriceps (H/Q) strength ratio based on concentric peak torque values (Hcon:Qcon) has traditionally been used to describe the potential for knee-joint destabilization. Because certain standard actions in soccer are explosive, the analysis of the H/Q strength ratio based on the rate of torque development (Hrtd:Qrtd) might also be useful in the evaluation of joint stability. The objective of this study was to compare the Hrtd:Qrtd between professional soccer players with heterogeneous values of Hcon:Qcon. Thirty-nine professional soccer players took part in the following procedures on different days: 1) Familiarization session with the isokinetic dynamometer, and 2) Two maximal isometric actions and five maximal concentric actions at 60°·s-1 for hamstrings (H) and quadriceps (Q). Participants were ranked according to their Hcon:Qcon ratio. The median third was excluded to form a high torque group (HTG), and a low torque group (LTG). Peak isometric (H) and concentric (H and Q) torques and rate of torque development (H) were significantly greater in the HTG group. Similarly, Hcon:Qcon (0.68 ± 0.02 vs. 0.52 ± 0.03) and Hrtd:Qrtd (0.54 ± 0.12 vs. 0.43 ± 0.16) were significantly greater in the HTG group than in the LTG group. There was no significant correlation between Hcon:Qcon and Hrtd:Qrtd. It can be concluded that Hcon:Qcon and Hrtd:Qrtd are determined, but not fully defined, by shared putative physiological mechanisms. Thus, the physiologic and clinical significance of Hcon:Qcon and Hrtd:Qrtd to an athlete’s individual evaluation might be different.

Key words: Muscular torque, isometric action, injury


           Key Points
  • Soccer players with high (0.66-0.70) and low (0.50-0.54) conventional concentric hamstrings:quadriceps ratios (H:Q) tend to demonstrate similar profiles (i.e., high and low, respectively) in their rate of the torque development H/Q ratio (H:Q).
  • The lack of a significant relationship between H:Q and H:Q suggests that these ratios are determined, but not fully defined, by shared putative physiological mechanisms.
  • Preseason screening programs that monitor hamstrings:quadriceps ratios should recognize that the physiologic and clinical significance of H:Q and Hrfd:Qrfd to an athlete’s individual evaluation might be different.
 
 
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