Search results for "Skeletal"
showing 10 items of 3025 documents
Electromyographic and Safety Comparisons of Common Lower Limb Rehabilitation Exercises for People With Hemophilia.
2020
Abstract Background Ankles and knees are commonly affected in people with hemophilia and thus are targets for prevention or rehabilitation. However, to our knowledge, no studies have evaluated muscle activity and safety during exercises targeting the lower limbs in people with hemophilia; this lack of information hinders clinical decision-making. Objective The aim of this study was to compare the tolerability of, safety of, and muscle activity levels obtained with external resistance (elastic or machine)-based and non–external resistance-based lower limb exercises in people with hemophilia. Design This was a cross-sectional study. Methods Eleven people who had severe hemophilia and were und…
Quantifying training intensity distribution in a group of Norwegian professional soccer players.
2011
Purpose:This study was designed to quantify the daily distribution of training intensity in a group of professional soccer players in Norway based on three different methods of training intensity quantification.Methods:Fifteen male athletes (age, 24 ± 5 y) performed treadmill test to exhaustion to determine heart rate and VO2 corresponding to ventilatory thresholds (VT1, VT2), maximal oxygen consumption (VO2max) and maximal heart rate. VT1 and VT2 were used to delineate three intensity zones based on heart rate. During a 4 wk period in the preseason (N = 15), and two separate weeks late in the season (N = 11), all endurance and on-ball training sessions (preseason: N = 378, season: N= 78) w…
Acute Neuromuscular and Endocrine Responses and Recovery to Single-Session Combined Endurance and Strength Loadings
2013
The purpose of this study was to investigate acute neuromuscular and endocrine responses and recovery to a single session of combined endurance and strength loading using 2 loading orders. Forty-two men were demographically matched to perform a single session of combined endurance + strength (E + S) or strength + endurance (S + E) loading. The strength loading was conducted on a leg press and included sets of power, maximal strength, and hypertrophic loads with an overall duration of 30 minutes. The endurance loading was conducted on a bike ergometer and performed by continuous cycling over 30 minutes at 65% of subject's individual maximal watts. Both loading conditions led to significant a…
Effect of combined electrostimulation and plyometric training on vertical jump height.
2002
This study investigated the influence of a 4-wk combined electromyostimulation (EMS) and plyometric training program on the vertical jump performance of 10 volleyball players.Training sessions were carried out three times weekly. Each session consisted of three main parts: EMS of the knee extensor muscles (48 contractions), EMS of the plantar flexor muscles (30 contractions), and 50 plyometric jumps. Subjects were tested before (week 0), during (week 2), and after the training program (week 4), as well as once more after 2 wk of normal volleyball training (week 6). Different vertical jumps were carried out, as well as maximal voluntary contraction (MVC) of the knee extensor and plantar flex…
Neural drive preservation after detraining following neuromuscular electrical stimulation training
2006
The purpose of the study was to investigate the behaviour of the central nervous system when 5 weeks of neuromuscular electrical stimulation (NMES) training was followed by 5 weeks of detraining. Nineteen males were divided into the neuromuscular electrostimulated group (EG, n=12) and the control group (CG, n=7). The training program consisted of 15 sessions of isometric NMES over a 5-week period. The EG subjects were tested before training (PRE), after 5 weeks of NMES training (POST) and after 5 weeks of detraining (DE) while CG subjects were only tested at PRE and at POST. Soleus (SOL) and gastrocnemii (GAS) maximal H-reflex and M-wave potentials were evoked at rest (i.e., H(max) and M(ma…
Mechanisms contributing to knee extensor strength loss after prolonged running exercise.
2002
The aim of this study was to identify the mechanisms that contribute to the decline in knee extensor (KE) muscles strength after a prolonged running exercise. During the 2 days preceding a 30-km running race [duration 188.7 ± 27.0 (SD) min] and immediately after the race, maximal percutaneous electrical stimulations (single twitch, 0.5-s tetanus at 20 and 80 Hz) were applied to the femoral nerve of 12 trained runners. Superimposed twitches were also delivered during isometric maximal voluntary contraction (MVC) to determine the level of voluntary activation (%VA). The vastus lateralis electromyogram was recorded. KE MVC decreased from pre- to postexercise (from 188.1 ± 25.2 to 142.7 ± 29.7…
Differences in contractile behaviour between the soleus and medial gastrocnemius muscles during human walking
2012
The functional roles of individual lower limb muscles during human walking may differ depending on walking speed or duration. In this study, 11 volunteers walked on a treadmill for 60 min at speeds corresponding to both optimal and 20% above optimal energetic cost of transport whilst oxygen consumption and medial gastrocnemius (MG) and soleus fascicle lengths were measured. Although energetic cost of transport was ∼12% higher at the faster speed, it remained constant over 60 min at both speeds, suggesting that humans can walk for prolonged periods at a range of speeds without compromising energetic efficiency. The fascicles of both muscles exhibited rather ‘isometric’ behaviour during the e…
Changes in motor unit activity and metabolism in human skeletal muscle during and after repeated eccentric and concentric contractions.
1977
This study was designed to investigate electromyographic (EMG), muscle glycogen and blood lactate changes in quadriceps muscle group during repeated 40 maximal eccentric and concentric contractions, and to follow the recovery in EMG, muscle glycogen and serum creatine kinase values during a 4 day period following the work test. The subjects were normal males and the test order (eccentric or concentric) was randomly selected. The results indicated first, that the EMG parameters (IEMG, AMUP), muscle glycogen and blood lactate changed in a similar manner during the both fatigue loads. Despite the high tension work no selective depletion of glycogen could be observed in the slow or fast twitch …
Neuromuscular Fatigue After a Ski Skating Marathon
2003
The aim of this study was to characterize neuromuscular fatigue in knee extensor muscles after a marathon skiing race (mean ± SD duration = 159.7 ± 17.9 min). During the 2 days preceding the event and immediately after, maximal percutaneous electrical stimulations (single twitch, 0.5-s tetanus at 20 and 80 Hz) were applied to the femoral nerve of 11 trained skiers. Superimposed twitches were also delivered during maximal voluntary contraction (MVC) to determine maximal voluntary activation (%VA). EMG was recorded from the vastus lateralis muscle. MVC decreased with fatigue from 171.7 ± 33.7 to 157.3 ± 35.2 Nm (-8.4%; p < 0.005) while %VA did not change significantly. The RMS measured du…
Frequent blood flow restricted training not to failure and to failure induces similar gains in myonuclei and muscle mass
2021
The purpose of the present study was to compare the effects of short-term high-frequency failure vs non-failure blood flow–restricted resistance exercise (BFRRE) on changes in satellite cells (SCs), myonuclei, muscle size, and strength. Seventeen untrained men performed four sets of BFRRE to failure (Failure) with one leg and not to failure (Non-failure; 30-15-15-15 repetitions) with the other leg using knee-extensions at 20% of one repetition maximum (1RM). Fourteen sessions were distributed over two 5-day blocks, separated by a 10-day rest period. Muscle samples obtained before, at mid-training, and 10-day post-intervention (Post10) were analyzed for muscle fiber area (MFA), myonuclei, an…