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Influence of hip-flexion angle on hamstrings isokinetic activity in sprinters.
J Athl Train. 2012 Jul-Aug; 47(4):390-5.JA

Abstract

CONTEXT

Hamstrings strains are common and debilitating injuries in many sports. Most hamstrings exercises are performed at an inadequately low hip-flexion angle because this angle surpasses 70° at the end of the sprinting leg's swing phase, when most injuries occur.

OBJECTIVE

To evaluate the influence of various hip-flexion angles on peak torques of knee flexors in isometric, concentric, and eccentric contractions and on the hamstrings-to-quadriceps ratio.

DESIGN

Descriptive laboratory study.

SETTING

Research laboratory.

PATIENTS AND OTHER PARTICIPANTS

Ten national-level sprinters (5 men, 5 women; age = 21.2 ± 3.6 years, height = 175 ± 6 cm, mass = 63.8 ± 9.9 kg).

INTERVENTION(S)

For each hip position (0°, 30°, 60°, and 90° of flexion), participants used the right leg to perform (1) 5 seconds of maximal isometric hamstrings contraction at 45° of knee flexion, (2) 5 maximal concentric knee flexion-extensions at 60° per second, (3) 5 maximal eccentric knee flexion-extensions at 60° per second, and (4) 5 maximal eccentric knee flexionextensions at 150° per second.

MAIN OUTCOME MEASURE(S)

Hamstrings and quadriceps peak torque, hamstrings-to-quadriceps ratio, lateral and medial hamstrings root mean square.

RESULTS

We found no difference in quadriceps peak torque for any condition across all hip-flexion angles, whereas hamstrings peak torque was lower at 0° of hip flexion than at any other angle (P < .001) and greater at 90° of hip flexion than at 30° and 60° (P < .05), especially in eccentric conditions. As hip flexion increased, the hamstrings-to-quadriceps ratio increased. No difference in lateral or medial hamstrings root mean square was found for any condition across all hip-flexion angles (P > .05).

CONCLUSIONS

Hip-flexion angle influenced hamstrings peak torque in all muscular contraction types; as hip flexion increased, hamstrings peak torque increased. Researchers should investigate further whether an eccentric resistance training program at sprint-specific hip-flexion angles (70° to 80°) could help prevent hamstrings injuries in sprinters. Moreover, hamstrings-to-quadriceps ratio assessment should be standardized at 80° of hip flexion.

Authors+Show Affiliations

Department of Physiotherapy, School of Health Sciences, University of Applied Sciences Western Switzerland, Lausanne, Switzerland. kenny.guex@hesav.chNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

22889654

Citation

Guex, Kenny, et al. "Influence of Hip-flexion Angle On Hamstrings Isokinetic Activity in Sprinters." Journal of Athletic Training, vol. 47, no. 4, 2012, pp. 390-5.
Guex K, Gojanovic B, Millet GP. Influence of hip-flexion angle on hamstrings isokinetic activity in sprinters. J Athl Train. 2012;47(4):390-5.
Guex, K., Gojanovic, B., & Millet, G. P. (2012). Influence of hip-flexion angle on hamstrings isokinetic activity in sprinters. Journal of Athletic Training, 47(4), 390-5. https://doi.org/10.4085/1062-6050-47.4.04
Guex K, Gojanovic B, Millet GP. Influence of Hip-flexion Angle On Hamstrings Isokinetic Activity in Sprinters. J Athl Train. 2012 Jul-Aug;47(4):390-5. PubMed PMID: 22889654.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Influence of hip-flexion angle on hamstrings isokinetic activity in sprinters. AU - Guex,Kenny, AU - Gojanovic,Boris, AU - Millet,Grégoire P, PY - 2012/8/15/entrez PY - 2012/8/15/pubmed PY - 2013/2/6/medline SP - 390 EP - 5 JF - Journal of athletic training JO - J Athl Train VL - 47 IS - 4 N2 - CONTEXT: Hamstrings strains are common and debilitating injuries in many sports. Most hamstrings exercises are performed at an inadequately low hip-flexion angle because this angle surpasses 70° at the end of the sprinting leg's swing phase, when most injuries occur. OBJECTIVE: To evaluate the influence of various hip-flexion angles on peak torques of knee flexors in isometric, concentric, and eccentric contractions and on the hamstrings-to-quadriceps ratio. DESIGN: Descriptive laboratory study. SETTING: Research laboratory. PATIENTS AND OTHER PARTICIPANTS: Ten national-level sprinters (5 men, 5 women; age = 21.2 ± 3.6 years, height = 175 ± 6 cm, mass = 63.8 ± 9.9 kg). INTERVENTION(S): For each hip position (0°, 30°, 60°, and 90° of flexion), participants used the right leg to perform (1) 5 seconds of maximal isometric hamstrings contraction at 45° of knee flexion, (2) 5 maximal concentric knee flexion-extensions at 60° per second, (3) 5 maximal eccentric knee flexion-extensions at 60° per second, and (4) 5 maximal eccentric knee flexionextensions at 150° per second. MAIN OUTCOME MEASURE(S): Hamstrings and quadriceps peak torque, hamstrings-to-quadriceps ratio, lateral and medial hamstrings root mean square. RESULTS: We found no difference in quadriceps peak torque for any condition across all hip-flexion angles, whereas hamstrings peak torque was lower at 0° of hip flexion than at any other angle (P < .001) and greater at 90° of hip flexion than at 30° and 60° (P < .05), especially in eccentric conditions. As hip flexion increased, the hamstrings-to-quadriceps ratio increased. No difference in lateral or medial hamstrings root mean square was found for any condition across all hip-flexion angles (P > .05). CONCLUSIONS: Hip-flexion angle influenced hamstrings peak torque in all muscular contraction types; as hip flexion increased, hamstrings peak torque increased. Researchers should investigate further whether an eccentric resistance training program at sprint-specific hip-flexion angles (70° to 80°) could help prevent hamstrings injuries in sprinters. Moreover, hamstrings-to-quadriceps ratio assessment should be standardized at 80° of hip flexion. SN - 1938-162X UR - https://www.unboundmedicine.com/medline/citation/22889654/Influence_of_hip_flexion_angle_on_hamstrings_isokinetic_activity_in_sprinters_ L2 - https://meridian.allenpress.com/jat/article-lookup/doi/10.4085/1062-6050-47.4.04 DB - PRIME DP - Unbound Medicine ER -