Effect of Hamstring-Emphasized Resistance Training on Hamstring:Quadriceps Strength Ratios

Abstract

A decreased hamstring:quadriceps (H:Q) ratio may put the hamstrings and anterior cruciate ligament (ACL) at increased risk of injury. Therefore, the purpose of this study was to evaluate H:Q ratios of 12 female National Collegiate Athletic Association soccer players, and to test the effects of a 6-week strength training program on these ratios. Each subject completed 2 practice sessions before a pretest. Subjects then completed 6 weeks of strength training that included the addition of 2 hamstring specific exercises, followed by a posttest. Peak torque during concentric and eccentric actions for both hamstrings and quadriceps was measured with an isokinetic dynamometer. Each muscle action was tested at 3 angular velocities in the following order: concentric 240, 180, and 60 degrees x s(-1) and eccentric 60, 180, and 240 degrees x s(-1). The H:Q strength ratio was evaluated using concentric muscle actions (concentric hamstrings:concentric quadriceps). This method is commonly used and is thus called the conventional ratio. Because concentric actions do not occur simultaneously in opposing muscles, a more functional assessment compares eccentric hamstring actions to concentric quadriceps actions. This functional ratio was also analyzed. Mean conventional and functional H:Q ratio data were analyzed using separate analysis of variance procedures with repeated measures on all factors (2 [Test] x 2 [Leg] x 3 [Angular Velocity]). The results revealed a significant main effect for factor (F test) with the functional ratio (p < 0.05) but not for the conventional ratio. The mean functional ratio increased from 0.96 +/- 0.09 in pretest to 1.08 +/- 0.11 in posttest. These results suggest that 6 weeks of strength training that emphasizes hamstrings is sufficient to significantly increase the functional ratio. The functional ratio after training exceeded 1.0, which is specifically recommended for prevention of ACL injuries.

Mapping current research trends on neuromuscular risk factors of non-contact ACL injury

“…For muscular capacity, 11 studies have looked into its association with sustaining a non-contact ACL injury (Ahmad, et al, 2006;Bee-Oh, et al, 2009;Bowerman, Smith, Carlson, & King, 2006;Grygorowicz, Kubacki, Pilis, Gieremek, & Rzepka, 2010;Hiemstra, Webber, MacDonald, & Kriellaars, 2007;Holcomb, Rubley, Lee, & Guadagnoli, 2007;Hosokawa, et al, 2011;Mattacola, et al, 2002;Roberts, Ageberg, Andersson, & Fridén, 2007;Wilkerson, et al, 2004;. These studies have associated muscular capacity with risks of acquiring ACL injury, validating ACL screening tools to be used in intervention programs to prevent ACL injury.…”

“…(Hiemstra, et al, 2007;Mattacola, et al, 2002;Roberts, et al, 2007;Wilkerson, et al, 2004; Isokinetic and isometric peak torques (Ahmad, et al, 2006;Bee-Oh, et al, 2009;Bowerman, et al, 2006;Grygorowicz, et al, 2010;Holcomb, et al, 2007;Hosokawa, et al, 2011). H:Q ratio Muscular Activation (Begalle, et al, 2012;Elias, et al, 2015;Nagano, et al, 2011;R.…”

Improving the Hamstrings-to-Quadriceps Strength Ratio in Sedentary Women: Comparison of Stabilization Training and Aerobic Training After a 6-Months Follow-up

“…It has been suggested that females with relatively lower H/Q ratios may be at a higher risk for injury (19,20). To prevent knee injuries, an H/Q ratio of 0.6 at a minimum (the hamstrings being 60% as strong as the quadriceps) is accepted (19,21). Evidence suggests that highly developed quadriceps muscles, to a great extent, contribute to the force capacity of hamstring muscles and imbalance of the muscles (19,22).…”

“…Some studies have examined the ways of improving H/Q ratios (23,24). It was suggested that plyometric exercises improved the ratio in physically active woman and whole body vibration training was effective on moderately active females (21,23,24). However, it is not exactly known whether aerobic exercises or spinal stability training has any impact on knee muscle strength and the H/Q ratio, and which exercise is more effective for the knee muscles in adult women.…”

Influência do treinamento excêntrico nas razões de torque de flexores/extensores do joelho

“…Apesar da importância do treinamento excêntrico para a melhora da estrutura e função muscular, prevenção e reabilitação de lesões, poucos são os estudos sobre os efeitos do treinamento excên-trico nas razões de torque entre os mús-culos isquiotibiais e quadríceps (razões I:Q) [16][17][18] . A razão de torque possibilita determinar os desequilíbrios musculares entre músculos antagonistas que atuam sobre uma articulação 19,20 .…”