Effect of Hamstring-Emphasized Resistance Training on Hamstring

Abstract

Holcomb, W.R., M.D. Rubley, H.J. Lee, and M.A.Guadagnoli. Effect of hamstring-emphasized resistance training on hamstring:quadriceps strength ratios. J. Strength Cond. Res. 21(1):41-47. 2007.-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 60Њ·s Ϫ1 and eccentric 60, 180, and 240Њ·s Ϫ1 . 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] ϫ 2 [Leg] ϫ 3 [Angular Velocity]). The results revealed a significant main effect for factor (F test) with the functional ratio (p Ͻ 0.05) but not for the conventional ratio. The mean functional ratio increased from 0.96 Ϯ 0.09 in pretest to 1.08 Ϯ 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.

Acute effects of static stretching on peak and end-range hamstring-to-quadriceps functional ratios

“…The functional H/Q strength ratios in our study are consistent with those reported in previous studies that calculated the functional ratio for knee extension during the entire range [15,22,[28][29][30][31][32][33] . Besides, the functional H/Q strength ratios reported in our study were higher for the end ranges of knee extension (1.0-1.10 for 60°/s and 1.51-1.54 for 180°/s) than during the entire range of knee extension.…”

“…If the pre-season hamstring to quadriceps ratio was lower than 0.6 at 180°/s angular velocity the risk of hamstring injury was 17 times higher in competitive sprinters [20] . Studies have reported that injury, detraining or training might have impacts on the changes of normal reciprocal strength distribution around the knee joint [21,22] . Few studies have investigated the impacts of static stretching during the pre-participation training routine on these strength ratios, and those data that are available are conflicting [23,24] .…”

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.…”

Effects of two different injury prevention resistance exercise protocols on the hamstring torque-angle relationship: a randomized controlled trial

“…Several injury prevention protocols including eccentric exercises such as the Nordic Curl (Gabbe, Branson, & Bennell, 2006;Petersen, Thorborg, Nielsen, Budtz-Jorgensen, & Holmich, 2011), double-leg dead lift (Holcomb, Rubley, Heather, & Guadagnoli, 2007), or leg curl using a fly wheel yo-yo machine (Askling, Karlsson, & Thorstensson, 2003) have shown to successfully attenuate the incidence of hamstring injuries (Opar, Williams, & Shield, 2012). These protective effects have been associated with some specific muscular adaptations such as increased isometric (Kilgallon, Donnelly, & Shafat, 2007) or dynamic (Mjølsnes, Arnason, Østhagen, Raastad, & Bahr, 2004) hamstring strength and a shift of the optimal knee flexion peak torque towards a more open angle position (Brughelli & Cronin, 2007;Clark, Bryant, Culgan, & Hartley, 2005).…”