Neuromuscular fatigue of the knee extensors during repeated maximal intensity intermittent-sprints on a cycle ergometer.

Introduction: We studied the time course of neuromuscular fatigue during maximal intensity intermittent-sprint cycling.

Methods: Eight participants completed 10, 10-s sprints interspersed with 180 s of recovery. The power outputs were recorded for each sprint.

Determining the activation of gluteus medius and the validity of the single leg stance test in chronic, nonspecific low back pain.

Objectives: To determine the activation of the gluteus medius in persons with chronic, nonspecific low back pain compared with that in control subjects, and to determine the association of the clinical rating of the single leg stance (SLS) with chronic low back pain (CLBP) and gluteus medius weakness.

Design: Cohort-control comparison.

Setting: Academic research laboratory.

Does performing drop jumps with additional eccentric loading improve jump performance?

Previous investigators have speculated that applying additional external load throughout the eccentric phase of the jumping movement could amplify the stretch-shortening cycle mechanism and modulate jumping performance and jump exercise intensity. The aims of this study, therefore, were to determine the effect of increased eccentric phase loading, as delivered using an elastic device, on drop jumps (DJs) performed from different drop heights. Of specific interest were changes in (a) the kinetics; eccentric and concentric impulse, rate of force development (RFD), concentric velocity and (b) the electromyographic (EMG) activity of leg muscles.

Knee extension fatigue attenuates repeated force production of the elbow flexors.

Non-local muscle fatigue has been demonstrated with unilateral activities, where fatiguing one limb alters opposite limb forces. Fewer studies have examined if non-local fatigue occurs with unrelated muscles. The purpose of this study was to investigate if knee extensors fatigue alters elbow flexors force and electromyography (EMG) activity.

Roller massager improves range of motion of plantar flexor muscles without subsequent decreases in force parameters.

Background: Limited dorsiflexion range of motion (ROM) has been linked to lower limb injuries. Improving limited ankle ROM may decrease injury rates. Static stretching (SS) is ubiquitously used to improve ROM but can lead to decreases in force and power if performed prior to the activity.

Specific and cross over effects of massage for muscle soreness: randomized controlled trial.

Purpose/background: Muscle soreness can negatively interfere with the activities of daily living as well as sports performance. In the working environment, a common problem is muscle tenderness, soreness and pain, especially for workers frequently exposed to unilateral high repetitive movements tasks. The aim of the study is therefore to investigate the acute effect of massage applied using a simple device Thera-band roller Massager on laboratory induced hamstring muscle soreness, and the potential cross over effect to the non-massaged limb.

Effect of head and limb orientation on trunk muscle activation during abdominal hollowing in chronic low back pain.

Background: Individuals with chronic low back pain (CLBP) have altered activations patterns of the anterior trunk musculature when performing the abdominal hollowing manœuvre (attempt to pull umbilicus inward and upward towards the spine). There is a subgroup of individuals with CLBP who have high neurocognitive and sensory motor deficits with associated primitive reflexes (PR). The objective of the study was to determine if orienting the head and extremities to positions, which mimic PR patterns would alter anterior trunk musculature activation during the hollowing manoeuvre.

Eight weeks of dynamic stretching during warm-ups improves jump power but not repeated or single sprint performance.

There is abundant research involving the acute effects of stretching on subsequent performance; however, there is little information on dynamic stretch training programmes on range of motion (ROM), power and speed measures. It was the objective of this research to examine the training consequences of active dynamic stretching (ADS) and static dynamic stretching (SDS). A repeated measures design compared the effects of 8 weeks of warm-ups incorporating two dynamic stretch modalities: ADS and SDS on squat jump (SJ), countermovement jump (CMJ), 20-m sprint performances and repeated sprint ability (RSA) and hip ROM in 37 male soccer players.

Instability resistance training across the exercise continuum.

Context: Instability resistance training (IRT; unstable surfaces and devices to strengthen the core or trunk muscles) is popular in fitness training facilities.

Objective: To examine contradictory IRT recommendations for health enthusiasts and rehabilitation.

Data Sources: A literature search was performed using MEDLINE, SPORT Discus, ScienceDirect, Web of Science, and Google Scholar databases from 1990 to 2012.

Prepubescent males are less susceptible to neuromuscular fatigue following resistance exercise.

Purpose: To determine if prepubescent and adult males have similar fatigue profiles following high and lower intensity knee extensions.

Methods: Ten male children and ten adults completed two sessions of three sets of high repetition (17 typical muscle endurance training) high repetition (High RM) or low repetition (seven typical strength training) maximum (Low RM) dynamic knee extensions. Voluntary and evoked contractile properties, heart rate (HR), and rating of perceived exertion (RPE) were assessed before and after each knee extension RM.

Foam rolling as a recovery tool after an intense bout of physical activity.

Purpose: The objective of this study is to understand the effectiveness of foam rolling (FR) as a recovery tool after exercise-induced muscle damage, analyzing thigh girth, muscle soreness, range of motion (ROM), evoked and voluntary contractile properties, vertical jump, perceived pain while FR, and force placed on the foam roller.

Methods: Twenty male subjects (≥3 yr of strength training experience) were randomly assigned into the control (n = 10) or FR (n = 10) group. All the subjects followed the same testing protocol.

The effect of double versus single oscillating exercise devices on trunk and limb muscle activation.

Purpose/background: Proper strengthening of the core and upper extremities is important for muscular health, performance, and rehabilitation. Exercise devices have been developed that attempt to disrupt the center of gravity in order to activate the trunk stabilizing muscles. The objective of this study was to analyze the trunk and shoulder girdle muscle activation with double and single oscillating exercise devices (DOD and SOD respectively) in various planes.

Olympic weightlifting and plyometric training with children provides similar or greater performance improvements than traditional resistance training.

A number of organizations recommend that advanced resistance training (RT) techniques can be implemented with children. The objective of this study was to evaluate the effectiveness of Olympic-style weightlifting (OWL), plyometrics, and traditional RT programs with children. Sixty-three children (10-12 years) were randomly allocated to a 12-week control OWL, plyometric, or traditional RT program.

Effects of surface instability on neuromuscular performance during drop jumps and landings.

Purpose: The purpose of this study was to investigate the effects of surface instability on measures of performance and activity of leg and trunk muscles during drop jumps and landings.

Methods: Drop jumps and landings were assessed on a force plate under stable and unstable (balance pad on top of the force plate) conditions. Performance measures (contact time, jump height, peak ground reaction force) and electromyographic (EMG) activity of leg and trunk muscles were tested in 27 subjects (age 23 ± 3 years) during different time intervals (preactivation phase, braking phase, push-off phase).

Exercise intensity progression for exercises performed on unstable and stable platforms based on ankle muscle activation.

Ankle sprains are a common sports injury. The literature focuses on the application of neuromuscular training for the improvement of balance, injury prevention and rehabilitation. However, there is a dearth of knowledge about the appropriate prescription of exercises using unstable platforms and surfaces.

Isometric training with maximal co-contraction instruction does not increase co-activation during exercises against external resistances.

The present investigation verified that strength is improved by a training programme consisting of repetitions of maximal isometric voluntary co-contractions without increasing co-activations during contractions against external resistances. Ten participants performed 12 training sessions (four sets of 6 × 4 second maximal isometric co-contraction of the elbow flexor and extensors, 3 days a week for 4 weeks). Surface electromyograms of triceps and biceps brachii were collected during maximal voluntary isometric elbow flexion and extension against a force transducer.

Roller-massager application to the hamstrings increases sit-and-reach range of motion within five to ten seconds without performance impairments.

Background: Foam rollers are used to mimic myofascial release techniques and have been used by therapists, athletes, and the general public alike to increase range of motion (ROM) and alleviate pressure points. The roller-massager was designed to serve a similar purpose but is a more portable device that uses the upper body rather than body mass to provide the rolling force.

Objectives/purpose: A roller massager was used in this study to examine the acute effects on lower extremity ROM and subsequent muscle length performance.

Massage and stretching reduce spinal reflex excitability without affecting twitch contractile properties.

Both stretching and massage can increase range of motion. Whereas the stretching-induced increases in ROM have been attributed to changes in neural and muscle responses, there is no literature investigating the ROM mechanisms underlying the interaction of stretch and massage. The objective of this paper was to evaluate changes in neural and evoked muscle responses with two types of massage and static stretching.

Exertional rhabdomyolysis in an acutely detrained athlete/exercise physiology professor.

The authors report a case of exercise-induced (exertional) rhabdomyolysis in a male athlete/exercise physiology professor who started a high-intensity resistance training program after a period of detraining. The subject performed 1 high-intensity resistance training session that consisted of 48 total sets of push-ups (24) and chin-ups (24) with no rest between the sets. Two days after the exercise session, the subject reported "Cola colored" urine.

The combination of plyometric and balance training improves sprint and shuttle run performances more often than plyometric-only training with children.

Because balance is not fully developed in children and studies have shown functional improvements with balance only training studies, a combination of plyometric and balance activities might enhance static balance, dynamic balance, and power. The objective of this study was to compare the effectiveness of plyometric only (PLYO) with balance and plyometric (COMBINED) training on balance and power measures in children. Before and after an 8-week training period, testing assessed lower-body strength (1 repetition maximum leg press), power (horizontal and vertical jumps, triple hop for distance, reactive strength, and leg stiffness), running speed (10-m and 30-m sprint), static and dynamic balance (Standing Stork Test and Star Excursion Balance Test), and agility (shuttle run).

Discovery of 1-(1,3,5-triazin-2-yl)piperidine-4-carboxamides as inhibitors of soluble epoxide hydrolase.

1-(1,3,5-Triazin-yl)piperidine-4-carboxamide inhibitors of soluble epoxide hydrolase were identified from high through-put screening using encoded library technology. The triazine heterocycle proved to be a critical functional group, essential for high potency and P450 selectivity. Phenyl group substitution was important for reducing clearance, and establishing good oral exposure.

Static stretching can impair explosive performance for at least 24 hours.

The aim of this study was to compare the effects of static vs. dynamic stretching (DS) on explosive performances and repeated sprint ability (RSA) after a 24-hour delay. Sixteen young male soccer players performed 15 minutes of static stretching (SS), DS, or a no-stretch control condition (CC) 24 hours before performing explosive performances and RSA tests.

A rapid rotation to an inverted seated posture inhibits muscle force, activation, heart rate and blood pressure.

Although previous studies have demonstrated neuromuscular and cardiovascular changes with slow inversion rates, emergencies, such as overturned vehicles and helicopters can occur rapidly. The purpose of this study was to investigate changes in neuromuscular and cardiovascular responses with rapid (1 s) and slower (3 s) transitions from upright to inverted seated positions. Twenty-two subjects performed separate and concurrent unilateral elbow flexion and leg extension maximal voluntary contractions (MVCs) for 6 s in an upright seated position and when inverted with 1 and 3 s rotations.