Effects of Dynamic Stretching on Strength, Muscle Imbalance, and Muscle Activation

COSTA, PABLO B.1; HERDA, TRENT J.2; HERDA, ASHLEY A.3; CRAMER, JOEL T.4

Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0000000000000138
Applied Sciences
Abstract

Purpose: This study aimed to examine the acute effects of dynamic stretching on concentric leg extensor and flexor peak torque, eccentric leg flexor peak torque, and the conventional and functional hamstring–quadriceps (H:Q) ratios.

Methods: Twenty-one women (mean ± SD age = 20.6 ± 2.0 yr, body mass = 64.5 ± 9.3 kg, height = 164.7 ± 6.5 cm) performed maximal voluntary isokinetic leg extension, flexion, and eccentric hamstring muscle actions at the angular velocities of 60°·s−1 and 180°·s−1 before and after a bout of dynamic hamstring and quadriceps stretching as well as a control condition.

Results: Leg flexion peak torque decreased under both control (mean ± SE for 60°·s−1 = 75.8 ± 4.0 to 72.4 ± 3.7 N·m, 180°·s−1 = 62.1 ± 3.2 to 59.1 ± 3.1 N·m) and stretching (60°·s−1 = 73.1 ± 3.9 to 65.8 ± 3.3 N·m, 180°·s−1 = 61.2 ± 3.3 to 54.7 ± 2.6 N·m) conditions, whereas eccentric hamstring peak torque decreased only after the stretching (60°·s−1 = 87.3 ± 5.1 to 73.3 ± 3.6 N·m, 180°·s−1 = 89.2 ± 4.4 to 77.0 ± 3.4 N·m) intervention (P ≤ 0.05). Stretching also caused a decrease in conventional H:Q (60°·s−1 = 0.58 ± 0.02 to 0.54 ± 0.02, 180°·s−1 = 0.67 ± 0.02 to 0.61 ± 0.03) and functional H:Q ratios (60°·s−1 = 0.69 ± 0.03 to 0.60 ± 0.03, 180°·s−1 = 1.00 ± 0.06 to 0.60 ± 0.03) (P ≤ 0.05).

Conclusions: Because dynamic stretching reduced concentric and eccentric hamstring strength as well as the conventional and functional H:Q ratios, fitness and allied-health professionals may need to be cautious when recommending dynamic rather than static stretching to maintain muscle force.

Author Information

1Human Performance Laboratory, Department of Kinesiology, California State University–San Bernardino, San Bernardino, CA; 2Biomechanics Laboratory, Department of Health, Sport and Exercise Sciences, University of Kansas, Lawrence, KS; 3Department of Ophthalmology, University of Kansas School of Medicine, Prairie Village, KS; and 4Department of Nutrition and Health Sciences, University of Nebraska–Lincoln, Lincoln, NE

Address for correspondence: Pablo B. Costa, Ph.D., Human Performance Laboratory, Department of Kinesiology, California State University–San Bernardino, 5500 University Parkway, HP-120, San Bernardino, CA 92407; E-mail: pcosta@csusb.edu.

Submitted for publication May 2013.

Accepted for publication August 2013.

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© 2014 American College of Sports Medicine