Search results for "hamstring"

Superimposing hip extension on knee flexion evokes higher activation in biceps femoris than knee flexion alone.

2021

Hamstring muscle function during knee flexion has been linked to hamstring injury and performance. However, it is unclear whether knee flexion alone (KF) requires similar hamstring electromyography (EMG) activity pattern to simultaneous hip extension and knee flexion (HE-KF), a combination that occurs in the late swing phase of sprinting. This study examined whether HE-KF maximal voluntary isometric contraction (MVIC) evokes higher (EMG) activity in biceps femoris long head (BFlh) and semitendinosus (ST) than KF alone. Effects of shank rotation angles were also tested. Twenty-one males performed the above-mentioned MVICs while EMG activity was measured along ST and BFlh. Conditions were com…

Activation and torque deficits in ACL-reconstructed patients 4 months post-operative

2001

This study compares knee extension and flexion torques and electromyographic (EMG) activity of normal and anterior cruciate ligament (ACL)-reconstructed knees during maximal unilateral isometric and isokinetic tests performed 4–5 months after ACL reconstruction. The subjects consisted of 3 age- and activity-matched groups of 6 subjects: a healthy control group (Ctrl) and 2 groups of patients, with Kenneth-Jones technique using autologous patellar-ligament graft (KJ group) and autologous graft from the semitendinosus tendon (ST group). When compared to the Ctrl group values, each patient group had significant bilateral extension torque deficits in isometric and at slow velocity concentric co…

Individual Region- and Muscle-specific Hamstring Activity at Different Running Speeds

2019

Introduction \ud Hamstring strain injuries typically occur in the proximal biceps femoris long head (BFlh) at high running speeds. Strain magnitude seems to be the primary determinant of strain injury, and may be regulated by muscle activation. In running, BFlh strain is largest in the proximal region, especially at high speeds. However, region-specific activity has not been examined. This study examined the proximal–distal and intermuscular activity of BFlh and semitendinosus (ST) as a function of increasing running speed.\ud \ud Methods \ud Thirteen participants ran at steady speeds of 4.1 (slow), 5.4 (moderate), and 6.8 m·s−1 (fast) on a treadmill. Region- and muscle-specific EMG activit…

Comparison of Electromyographic Activity During Hip Extension Exercises Under Gravitational or Inertial Loading Conditions.

2021

Background: Hamstring injury prevention programs include strengthening, especially eccentric exercises using both gravitational and inertial loading. Inertial exercises are characterized by eccentric contractions of high intensity and velocity. This study aimed to analyze the muscular activation of the biceps femoris (BF), semitendinosus (ST), gluteus maximus (GM), and gracilis (GC) muscles during hip extension (HE) exercises performed under both gravitational and inertial loading conditions. Hypothesis: Inertial training would generate a greater activation of HE muscles than gravitational training. Study Design: Cross-sectional study. Level of Evidence: Level 4. Methods: Fifteen resistance…

Effects of Combined Strength and Sprint Training on Lean Mass, Strength, Power and Sprint Performance in Masters Road Cyclists

2017

Del Vecchio, L, Stanton, R, Reaburn, P, Macgregor, C, Meerkin, J, Villegas, J, and Korhonen, MT. Effects of combined strength and sprint training on lean mass, strength, power, and sprint performance in masters road cyclists. J Strength Cond Res 33(1): 66-79, 2019-Strength and sprint-training exercises are integral part of training in many younger endurance cyclists to improve cycling efficiency and sprinting ability. This study was undertaken to examine whether muscle and performance characteristics could be improved in endurance-trained masters cyclist by adding strength and sprint-training stimuli into their training regimen. Twenty-five masters road cyclists were assigned to a combined …

Exercise for fitness does not decrease the muscular inactivity time during normal daily life

2012

The time spent in sedentary behaviors has been shown to be independent of exercise in epidemiological studies. We examined within an individual whether exercise alters the time of muscular inactivity within his/her normal daily life. Quadriceps and hamstring muscle electromyographic activities and heart rate were measured during 1 to 6 days of normal daily living of ordinary people. Of 84 volunteers measured, 27 (15 men, 12 women, 40.7 years ± 16.5 years) fulfilled the criteria of having at least 1 day with and 1 day without exercise for fitness (total of 87 days analyzed, 13.0 h ± 2.5 h/day). Reported exercises varied from Nordic walking to strength training and ball games lasting 30 min-1…

Quasi-Fractional Models of Human Tendons Hereditariness

2018

In this study, the authors, after collecting a series of experimental evidences following a creep and relaxation tendon campaign, propose a non-linear model of the viscoelastic behavior of the tendons. The ligaments investigated are the patellars and the hamstrings. The analytical model proposed by the authors aims to explain the non-linear hereditary behavior of these tissues and proposes an approach with which to develop a hereditary fractional-order non-linear model.

AB0929 Balance in fibromyalgia is not related with lower limb strength

2017

Background Postural control, that depends on many sensory contributors and motor skills, is altered in people with fibromyalgia (FM) 1–3. Knowing those contributors that could be impaired in this population is important to design an appropriate balance therapy. Objectives Due to the fact that people with FM use to present a strength loss 7, our main goal was to explore the relation between postural control and lower limb strength in this population. Further, the sensory inputs contributors to the postural control were assessed. Methods A cross-sectional study was conducted in a sample of 40 FM patients. A force platform was used to assess postural control under five bipedal conditions: i) e…

Specific distribution of cross-sectional area in each hamstring muscle of sprint runners and relationship between those and sprint performance

2018

Progression of untreated mild thoracic Scheuermann's kyphosis – Radiographic and functional assessment after mean follow-up of 46 years

2017

There is no data available on the radiographic development of the Scheuermann's deformity. Our purpose was to investigate radiographic deformity progression and the relation between kyphosis progression and clinical outcome in patients with untreated Scheuermann's kyphosis.Thoracic kyphosis (Th4-Th12) was measured from standing lateral radiographs in 19 patients at baseline and after mean 46-year follow-up. Mean age at baseline was 19.2 and at follow-up 64.7 years. At follow-up, height, weight, hand grip strength, and hamstring tightness were measured, and sit-to-stand and walking tests were performed. Additionally general health and quality of life questionnaires were administered.The mean…