A pilot study to determine the effect of trunk and hip focused neuromuscular training on hip and knee isokinetic strength

Abstract

Objective-The objective was to determine the effect of trunk focused neuromuscular training (TNMT) on hip and knee strength. The hypothesis was that TNMT would increase standing isokinetic hip abduction, but not knee flexion/extension, strength.Methods-21 high-school female volleyball players (14 TMNT, mean age 15.4 (1.4) years, weight 170.5 (5.0) cm, height 64.1 (8.5) kg and 7 controls, mean age 16.0 (1.7) years, height 173.4 (10.0) cm, weight 63.9 (5.3) kg; p>0.05) were recruited to participate in this study. The 14 TNMT subjects participated in a TNMT protocol (twice weekly) over a 10 week period in addition to their standard once-weekly off-season strength training. Standing isokinetic hip abduction strength and seated knee flexion/extension strength were measured before and after TNMT.Results-A significant interaction of group and time was observed. The TNMT group increased isokinetic hip abduction strength approximately 15% (13.5% in the dominant leg: mean (SD) 46.6 (10.1) to 52.9 (11.4) foot-pounds and 17.1% in the non-dominant leg: 46.1 (10.4) to 54.0 (10.7) foot-pounds; p=0.01). There was no difference in the control group in pre-test versus post-test measures. Post-test results also indicated no effect of TNMT on isokinetic knee extension (p=0.57) or knee flexion (p=0.57) strength.Conclusions-Ten weeks of TNMT increased standing hip abduction strength in female athletes. Increased hip abduction strength and recruitment may improve the ability of female athletes to increase control of lower limb alignment and decrease knee loads resulting from increased trunk displacement during sports activities. Female athletes are currently reported to be 4-6 times more likely to sustain a sport-related non-contact anterior cruciate ligament (ACL) injury than are male athletes. 1-3 Altered neuromuscular trunk and hip control strategies during the execution of sports movements may result in lower limb joint mechanics (motions and loads) that increase the risk of ACL injury in female athletes. Hip abduction strength and control may be the critical modulator between altered trunk control and ultimate lower limb knee loads responsible for ACL rupture.During peak growth velocity of both height and mass, the tibia and femur grow at rapid rates in pubertal athletes of both sexes. 4 Rapid growth of the two longest levers in the human body initiates height increases and increased height of the centre of mass, making muscular control of trunk more challenging. In addition, increased body mass and longer joint levers leads to the development of greater joint forces and moments that are more difficult to balance and dampen at the lower limb joints during high-velocity manoeuvres. [5][6][7] Brent et al used a longitudinal study approach to determine that in a population of 11-22-year-old athletes, male athletes increased their relative hip abduction strength at a significantly greater rate than did female athletes. 8 Female athletes also showed decreased power and increased valgus knee motion during jumping and landing as...

The 2012 ABJS Nicolas Andry Award: The Sequence of Prevention: A Systematic Approach to Prevent Anterior Cruciate Ligament Injury

“…Collectively, our training studies [30,41,58,63,64,74,75] indicate a combination of plyometric, resistance, and balance training with technique biofeedback may further maximize the effectiveness of preseason training and ACL injury prevention strategies. The additive effect of improved performance measures and neuromuscular function, particularly in athletes with specific deficits or altered biomechanics, may lead to more efficacious, efficient, targeted ACL injury prevention programs.…”

“…In relation to high-risk lower extremity biomechanics, plyometric and balance training can reduce high-risk knee abduction and flexion measures [29,64,74]. Trunk-focused neuromuscular training increases hip abduction strength which may improve neuromuscular control of lower limb alignment and decrease knee loads that occur as a result of increased trunk displacement during sports activities [58]. Neuromuscular training programs that target core and lower extremity strength can improve single-limb postural stability and neuromuscular control [13,83].…”

“…Our research has focused on identifying targeted training protocols to more effectively and efficiently alter high-risk landing and cutting biomechanics and improve neuromuscular deficiencies. We compared the effects of maximum-effort plyometric training versus dynamic stabilization exercises, trunk-and hip-focused training, and functional proprioceptive training on power, strength, coordination, and high-risk lower extremity biomechanics (ie, limb asymmetry, high ground reaction forces, knee abduction measures, and knee flexion measures) [13,29,58,60,64,74,83]. In relation to high-risk lower extremity biomechanics, plyometric and balance training can reduce high-risk knee abduction and flexion measures [29,64,74].…”

A Predictive Model to Estimate Knee-Abduction Moment: Implications for Development of a Clinically Applicable Patellofemoral Pain Screening Tool in Female Athletes

“…21,45 Neuromuscular training focused on the trunk and hip increased standing hip-abduction strength in females. 12 This training may improve the ability of females to control for the increased height of their COM and improve dynamic lower extremity alignments to reduce loads that may contribute to the onset of PFP. Accordingly, Labella et al 46 instituted a preseason neuromuscular-training program for young females and found that the prevalence of knee pain at postseason follow-up was reduced.…”

“…Peak hipabduction torques were recorded, and all examinations were performed by a single investigator. 12 Lower Extremity Segment Length and Alignment Measurements. Before biomechanical testing, we conducted a static standing trial in which the participant was instructed to stand still with foot placement standardized to the laboratory coordinate system.…”