Dataset Information

The muscle pre-activity timing of the hamstrings and quadriceps during 180° and 360° rotational jump landings in healthy female subjects.

ABSTRACT: Background/Objective:The muscle activity before the initial contact between during jump landings is referred to as the pre-activity. The muscle pre-activity that occur during jump landing are considered to be an important predictor of non-contact anterior cruciate ligament (ACL) injury risk. ACL injury prevention programs have been widely conducted; these programs are generally focused on increasing the muscle pre-activity and include rotational jump landing. The purpose of this study was to investigate the timing of the muscle pre-activity of the hamstrings and quadriceps during 180° and 360° rotational jump landing. Methods:The participants were 10 healthy females. Electromyography was conducted on the knee joint muscles of the left leg (the non-dominant leg) during clockwise 180° and 360° rotational jump landings. Results:The muscle pre-activities during 180° rotational jump landing was VM: 35.68?±?11.22 msec, RF: 38.05?±?14.77 msec, VL: 47.10?±?19.96 msec, BF: 115.63?±?30.48 msec and SM: 136.45?±?47.52 msec. And the muscle pre-activities during 360° rotational jump landing was VM: 45.25?±?17.41 msec, RF: 42.38?±?13.35 msec, VL: 48.75?±?19.20 msec, BF: 132.20?±?46.74 msec and SM: 140.70?±?40.64 msec. For both the 180° rotational jump landing and the 360° jump landing, the pre-activities of the hamstrings occurred significantly earlier than those of the quadriceps (p?

SUBMITTER: Bai D

PROVIDER: S-EPMC6700471 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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The muscle pre-activity timing of the hamstrings and quadriceps during 180° and 360° rotational jump landings in healthy female subjects.

Bai Daisuke D Okada Yohei Y Fukumoto Takahiko T Ogawa Munehiro M Tanaka Yasuhito Y

Asia-Pacific journal of sports medicine, arthroscopy, rehabilitation and technology 20190125

<h4>Background/objective</h4>The muscle activity before the initial contact between during jump landings is referred to as the pre-activity. The muscle pre-activity that occur during jump landing are considered to be an important predictor of non-contact anterior cruciate ligament (ACL) injury risk. ACL injury prevention programs have been widely conducted; these programs are generally focused on increasing the muscle pre-activity and include rotational jump landing. The purpose of this study wa ...[more]

PMID: 31453110

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Project description:PurposeThe purpose was to assess if variation in sagittal plane landing kinematics is associated with variation in neuromuscular activation patterns of the quadriceps-hamstrings muscle groups during drop vertical jumps (DVJ).MethodsFifty female athletes performed three DVJ. The relationship between peak knee and hip flexion angles and the amplitude of four EMG vectors was investigated with trajectory-level canonical correlation analyses over the entire time period of the landing phase. EMG vectors consisted of the {vastus medialis(VM),vastus lateralis(VL)}, {vastus medialis(VM),hamstring medialis(HM)}, {hamstring medialis(HM),hamstring lateralis(HL)} and the {vastus lateralis(VL),hamstring lateralis(HL)}. To estimate the contribution of each individual muscle, linear regressions were also conducted using one-dimensional statistical parametric mapping.ResultsThe peak knee flexion angle was significantly positively associated with the amplitudes of the {VM,HM} and {HM,HL} during the preparatory and initial contact phase and with the {VL,HL} vector during the peak loading phase (p<0.05). Small peak knee flexion angles were significantly associated with higher HM amplitudes during the preparatory and initial contact phase (p<0.001). The amplitudes of the {VM,VL} and {VL,HL} were significantly positively associated with the peak hip flexion angle during the peak loading phase (p<0.05). Small peak hip flexion angles were significantly associated with higher VL amplitudes during the peak loading phase (p = 0.001). Higher external knee abduction and flexion moments were found in participants landing with less flexed knee and hip joints (p<0.001).ConclusionThis study demonstrated clear associations between neuromuscular activation patterns and landing kinematics in the sagittal plane during specific parts of the landing. These findings have indicated that an erect landing pattern, characterized by less hip and knee flexion, was significantly associated with an increased medial and posterior neuromuscular activation (dominant hamstrings medialis activity) during the preparatory and initial contact phase and an increased lateral neuromuscular activation (dominant vastus lateralis activity) during the peak loading phase.

Project description:The purpose was to evaluate the dynamic knee control during a drop jump test following injury of the anterior cruciate ligament injury (ACL) using finite helical axes. Persons injured 17-28 years ago, treated with either physiotherapy (ACLPT, n = 23) or reconstruction and physiotherapy (ACLR, n = 28) and asymptomatic controls (CTRL, n = 22) performed a drop jump test, while kinematics were registered by motion capture. We analysed the Preparation phase (from maximal knee extension during flight until 50 ms post-touchdown) followed by an Action phase (until maximal knee flexion post-touchdown). Range of knee motion (RoM), and the length of each phase (Duration) were computed. The finite knee helical axis was analysed for momentary intervals of ~15° of knee motion by its intersection (?AP position) and inclination (?AP Inclination) with the knee's Anterior-Posterior (AP) axis. Static knee laxity (KT100) and self-reported knee function (Lysholm score) were also assessed. The results showed that both phases were shorter for the ACL groups compared to controls (CTRL-ACLR: Duration 35±8 ms, p = 0.000, CTRL-ACLPT: 33±9 ms, p = 0.000) and involved less knee flexion (CTRL-ACLR: RoM 6.6±1.9°, p = 0.002, CTRL-ACLR: 7.5 ±2.0°, p = 0.001). Low RoM and Duration correlated significantly with worse knee function according to Lysholm and higher knee laxity according to KT-1000. Three finite helical axes were analysed. The ?AP position for the first axis was most anterior in ACLPT compared to ACLR (?AP position -1, ACLPT-ACLR: 13±3 mm, p = 0.004), with correlations to KT-1000 (rho 0.316, p = 0.008), while the ?AP inclination for the third axis was smaller in the ACLPT group compared to controls (?AP inclination -3 ACLPT-CTRL: -13±5°, p = 0.004) and showed a significant side difference in ACL injured groups during Action (Injured-Non-injured: 8±2.7°, p = 0.006). Small ?AP inclination -3 correlated with low Lysholm (rho 0.391, p = 0.002) and high KT-1000 (rho -0.450, p = 0.001). Conclusions Compensatory movement strategies seem to be used to protect the injured knee during landing. A decreased ?AP inclination in injured knees during Action suggests that the dynamic knee control may remain compromised even long after injury.

Project description:BackgroundNeuromuscular electrical stimulation (NMES) may prevent muscle atrophy, accelerate rehabilitation and enhance blood circulation. Yet, one major drawback is that patient compliance is impeded by the discomfort experienced. It is well-known that the size and placement of electrodes affect the comfort and effect during high-intensity NMES. However, during low-intensity NMES the effects of electrode size/placement are mostly unknown. Therefore, the purpose of this study was to investigate how electrode size and pragmatic placement affect comfort and effect of low-intensity NMES in the thigh and gluteal muscles.MethodsOn 15 healthy participants, NMES-intensity (mA) was increased until visible muscle contraction, applied with three electrode sizes (2 × 2 cm, 5 × 5 cm, 5 × 9 cm), in three different configurations on quadriceps and hamstrings (short-transverse (ST), long-transverse (LT), longitudinal (L)) and two configurations on gluteus maximus (short-longitudinal (SL) and long-longitudinal (LL)). Current-density (mA/cm2) required for contraction was calculated for each electrode size. Comfort was assessed with a numerical rating scale (NRS, 0-10). Significance was set to p < 0.05 and values were expressed as median (inter-quartile range).ResultsOn quadriceps the LT-placement exhibited significantly better comfort and lower current intensity than the ST- and L-placements. On hamstrings the L-placement resulted in the best comfort together with the lowest intensity. On gluteus maximus the LL-placement demonstrated better comfort and required less intensity than SL-placement. On all muscles, the 5 × 5 cm and 5 × 9 cm electrodes were significantly more comfortable and required less current-density for contraction than the 2 × 2 cm electrode.ConclusionDuring low-intensity NMES-treatment, an optimized electrode size and practical placement on each individual muscle of quadriceps, hamstrings and gluteals is crucial for comfort and intensity needed for muscle contraction.

Project description:Hamstring strains are the most common injury in multiple sprint sports, with inadequate eccentric hamstring strength and fatigue identified as important risk factors. Resistance training interventions aimed at reducing injury risk typically focus on the development of maximum strength, while little is known about the impact of training on hamstring fatigue resistance. The present study compared the effects of strength endurance (SE) with a strength intervention (S) on the eccentric hamstring strength decline induced by a simulated soccer match. Twenty-one female soccer players were randomly assigned to a S group (n = 10) or a SE group (n = 11). Hamstrings and quadriceps isokinetic concentric and eccentric peak torque (PT) were assessed at 120°.s-1 and hamstrings-to-quadriceps ratio (HEcc:QCon) calculated, pre- and immediately post a 90-min simulated match (BEAST90). This was repeated following a 7-week intervention of either three to five sets of 6RM leg curl and stiff-leg deadlift with 3-min inter-set rest (S), or the same exercises performed using three sets of 12-20 RM with 45-90 s inter-set rest (SE). At baseline, the simulated match led to significant declines in hamstrings eccentric peak torque (EccPT) in both groups in both dominant (D) and non-dominant (ND) legs [SE: (D: -15.5, ND: -15.6%), P = 0.001 to 0.016; S: (D: -12.3%, ND: -15.5%), P = 0.001 to 0.018]. After the 7-week intervention, we observed a group?intervention?match interaction such that there was no significant decline in EccPT in the SE group following the simulated match (D: 5.3%, ND: 2.0%), but there remained significant declines in the S group (D: -14.2%, ND: -15.5%, P = 0.018-0.001). Similarly, in the SE group, there was a significant decrease in the HEcc:QCon in D before (-14.2%, P = 0.007), but not after the training intervention, whereas declines were observed in the S group both at baseline, and following the intervention (D: -13.9%, ND: -15.6%, P = 0.045). These results demonstrate that SE training can reduce the magnitude of the EccPT decline observed during soccer competition. As inadequate eccentric strength and fatigue are both risk factors for hamstring injury, SE training should be considered along with the development of peak eccentric strength, as a component of programs aimed at reducing injury risk in multiple-sprint sports.

Dataset Information

The muscle pre-activity timing of the hamstrings and quadriceps during 180° and 360° rotational jump landings in healthy female subjects.

Publications

The muscle pre-activity timing of the hamstrings and quadriceps during 180° and 360° rotational jump landings in healthy female subjects.

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