Search results for "electromyography"
showing 10 items of 672 documents
Neuromuscular Adaptations to Short-Term High-Intensity Interval Training in Female Ice-Hockey Players
2019
Kinnunen, J-V, Piitulainen, H, and Piirainen, JM. Neuromuscular adaptations to short-term high-intensity interval training in female ice-hockey players. J Strength Cond Res 33(2): 479-485, 2019-High-intensity interval training (HIIT)-related neuromuscular adaptations, changes in force production, and on-ice performance were investigated in female ice-hockey players during preseason. Fourteen Finnish championship level ice-hockey players (average age 22 ± 3 years) participated in 2½-week HIIT. Both spinal (H-reflex) and supraspinal (V-wave) neuromuscular responses of the soleus muscle were recorded before and after the training period. Static jump (SJ) and countermovement jump heights, plant…
Mechanical efficiency of locomotion in females during different kinds of muscle action
1990
The mechanical efficiencies (ME) of pure positive and pure negative work as well as of stretch-shortening cycle (SSC) exercise were investigated with a special sledge apparatus. The subjects were 20 young females who performed six different types of submaximal exercise: two of pure concentric exercise (positive work), two of pure eccentric exercise (negative work) and two SSC exercises. The work intensities were determined individually, from the recordings of distance obtained during a single maximal concentric exercise. Each exercise involved 60 muscle actions lasting a total of 3 min per testing condition. The MEs of pure positive work with intensities of 30% and 60% maximum (C30 and C60 …
A fully automated system for the evaluation of masseter silent periods.
1997
Exteroceptive suppression of masseter muscle activity, 'masseter inhibitory reflex', comprises one or 2 silent periods (SP1 and SP2) interrupting the voluntary activation. The main problem when evaluating exteroceptive suppression is the lack of an objective and precise measure for the onset and end of the silent period which so far has not been overcome by various automated systems. We describe a new fully automated system for determining the onset and end of the masseter silent period. The decision approach is essentially based upon deterministic properties of median filters which are used to partition the local variances of the EMG traces into constant segments and edges between them. Th…
The effects of high heeled shoes on female gait: a review.
2013
Walking is the most common form of human locomotion. From a motor control perspective, human bipedalism makes the task of walking extremely complex. For parts of the step cycle, there is only one foot on the ground, so both balance and propulsion are required in order for the movement to proceed smoothly. One condition known to compound the difficulty of walking is the use of high heeled shoes, which alter the natural position of the foot–ankle complex, and thereby produce a chain reaction of (mostly negative) effects that travels up the lower limb at least as far as the spine. This review summarises recent studies that have examined acute and chronic effects of high heels on balance and lo…
Strength training induced adaptations in neuromuscular function of premenopausal women with fibromyalgia: comparison with healthy women.
2000
Objective—To investigate the eVects of 21 weeks’ progressive strength training on neuromuscular function and subjectively perceived symptoms in premenopausal women with fibromyalgia (FM). Methods—Twenty one women with FM were randomly assigned to experimental (FMT) or control (FMC) groups. Twelve healthy women served as training controls (HT). The FMT and HT groups carried out progressive strength training twice a week for 21 weeks. The major outcome measures were muscle strength and electromyographic (EMG) recordings. Secondary outcome measures were pain, sleep, fatigue, physical function capacity (Stanford Health Assessment Questionnaire), and mood (short version of Beck’s depression inde…
Heterogeneity of muscle activity during sedentary behavior
2016
Replacing sitting by standing has been hypothesized to reduce the health risks of sitting, based on the assumption that muscles are passive during sitting and active during standing. Interventions have been more effective in overweight (OW) than in normal weight (NW) individuals, but subjects’ muscle activities have not been quantified. This study compared quadriceps and hamstring muscle electromyographic (EMG) activity between 57 NW (body mass index (BMI) 22.5 ± 1.5 kg/m2, female n = 36) and 27 OW (BMI 28.4 ± 2.9 kg/m2, female n = 8) subjects during non-fatiguing standing (15 s, EMGstanding) and sitting (30 min). EMG amplitude was normalized to EMG measured during maximal isometric knee e…
Neuromuscular fatigue induced by a 90-minute soccer game modeling.
2012
This study aimed to quantify neuromuscular fatigue induced by a soccer game. Eight amateur soccer players (age 20.4 ± 1.3 years, mass 70.4 ± 6.9 kg, and height 174.9 ± 5.2 cm) reproduced a 90-minute soccer game modeling composed of two 45-minute periods separated by a 15-minute rest. Torque of quadriceps and hamstring muscle groups associated with electromyography, sprint speed, and vertical jump height was assessed before, at halftime, and immediately after the modeling. Most physical qualities decreased throughout the game with greater decays at match end than at halftime. Contrarily to quadriceps muscles, hamstring torque impairments were not accompanied by electromyographic activity red…
Effect of fatigue on the precision of a whole-body pointing task.
2005
We addressed the issue of the possible degradation of the aiming precision of a whole-body pointing task, when movement coordination is deranged by selective fatigue of the postural task component. The protocol involved continuous repetition (0.1 Hz frequency) of rapid whole-body pointing trials toward a target located beyond arm length, starting from stance and requiring knee flexion. Six healthy human subjects repeated the trials until exhaustion. Such repetition led to electromyography signs of fatigue in rectus femoris (active in body lowering and raising), but not in deltoid (prime mover for arm reaching component). Rectus femoris fatigue affected the equilibrium control strategy, sinc…
Muscle damage induced by stretch-shortening cycle exercise
1998
Strenuous stretch-shortening cycle exercise was used as a model to study the leakage of proteins from skeletal muscle.The analysis included serum levels of creatine kinase (S-CK), myoglobin (S-Mb), and carbonic anhydrase (S-CA III). Blood samples from power- (N=11) and endurance-trained (N=10) athletes were collected before, 0, and 2 h after the exercise, which consisted of a total of 400 jumps.The levels of all determined myocellular proteins increased immediately after the exercise (P0.05-0.001) among both subject groups. In the endurance group, the protein levels increased (P0.05-0.001) further during the following 2 h after the exercise, and the ratio of S-CA III and S-Mb decreased (P0.…
Time Course of Neuromuscular Alterations during a Prolonged Running Exercise
2004
PLACE, N., R. LEPERS, G. DELEY, and G. Y. MILLET. Time Course of Neuromuscular Alterations during a Prolonged Running Exercise. Med. Sci. Sports Exerc., Vol. 36, No. 8, pp. 1347–1356, 2004. Purpose: This study investigated the time course of contractile and neural alterations of knee extensor (KE) muscles during a long-duration running exercise. Methods: Nine well-trained triathletes and endurance runners sustained 55% of their maximal aerobic velocity (MAV) on a motorized treadmill for a period of 5 h. Maximal voluntary contraction (MVC), maximal voluntary activation level (%VA), and electrically evoked contractions (single and tetanic stimulations) of KE muscles were evaluated before, aft…