Validity and Reliability of Handheld Dynamometry to Assess Isometric Hamstrings and Quadriceps Strength at Varying Muscle Lengths.

Context: The hamstrings are the most commonly injured muscle in sports and are especially injury prone in lengthened positions. Measuring knee muscle strength in such positions could be relevant to establish injury risk. Handheld dynamometry has been shown to be a valid, reliable, and practical tool to measure isometric muscle strength clinically.

Current warm-up practices before maximal sprinting in track-and-field (athletics).

Background: Warm-up is commonly performed by track-and-field athletes before performing maximal sprinting activities. Whilst some warm-up strategies may enhance athletes' physical and mental readiness, less is known about the current athletes' behaviors and warm-up practices in track and field. Therefore, this study aimed to identify the warm-up practices in a population of athletes performing in sprinting disciplines.

Hamstring Muscle Injuries and Hamstring Specific Training in Elite Athletics (Track and Field) Athletes.

Objective: We aimed to describe hamstring muscle injury (HMI) history and hamstring specific training (HST) in elite athletes. A secondary aim was to analyse the potential factors associated with in-championships HMI.

Methods: We conducted a prospective cohort study to collect data before and during the 2018 European Athletics Championships.

Successful Return to Performance After COVID-19 Infection in an Elite Athlete.

Purpose: To present training load (TL) and heart-rate variability (HRV) in an elite sprinter monitored before, during, and after a COVID-19 infection until successful return to performance.

Methods: TL, subjective morning fatigue (MF), and supine HRV were monitored during a 12-week period.

Results: During a high-TL period (training camp), MF and heart rate increased and vagally mediated HRV variables decreased.

Acute Effects of the Wim Hof Breathing Method on Repeated Sprint Ability: A Pilot Study.

The Wim Hof breathing method (WHBM) combines periods of hyperventilation (HV) followed by voluntary breath-holds (BH) at low lung volume. It has been increasingly adopted by coaches and their athletes to improve performance, but there was no published research on its effects. We determined the feasibility of implementing a single WHBM session before repeated sprinting performance and evaluated any acute ergogenic effects.

Pacing Strategy in Men's 400 m Hurdles Accounting for Temporal and Spatial Characteristics of Elite Athletes.

The final result in a 400 m hurdles race (400mH) is relative to the motor preparation, technique of clearing hurdles as well as the adopted strategy of the race, including temporal aspects (split times in particular parts of the race) and spatial elements (the number of strides taken between subsequent hurdles). The objective of the study was to identify an optimal strategy for the 400mH race, including the stride pattern and split times. Data employed for this study were derived from results of 273 races held during the men's finals of international events (Olympic Games, World and European Championships) held from 1968 to 2015.

Low Horizontal Force Production Capacity during Sprinting as a Potential Risk Factor of Hamstring Injury in Football.

Clear decreases in horizontal force production capacity during sprint acceleration have been reported after hamstring injuries (HI) in football players. We hypothesized that lower is associated with a higher HI occurrence in football players. We aimed to analyze the association between sprint running horizontal force production capacities at low () and high () velocities, and HI occurrence in football.

From Sedentary and Physical Inactive Behaviours to an Ultra Cycling Race: A Mixed-Method Case Report.

In faculties of health sciences, almost 30% of nursing students exercise less than once a week. This mixed-method case report presents the 38-month evolution of the physiological and psychological health parameters of a sedentary and physically inactive nursing student. During this period, she first took part in a one-semester institutional physical activity (PA) program that was offered by her university before being selected for participation in the Race Across America (RAAM) with a university relay team.

Participating In The Race Across AMerica In A Team Of Eight Cyclists: Do Not Neglect Crew Preparation.

Background: The Race Across AMerica (RAAM) is considered as one of the longest, and most difficult cycling races in the world. It can be performed in solo or in relay of two, four or eight persons.

Purpose/method: The aim of the present study was to investigate several physiological, perceptual and psychological responses before, during and after RAAM in a team of eight amateur cyclists.

Postural Control Follows a Bi-Phasic Alteration Pattern During Mountain Ultra-Marathon.

It is well knows that postural control (PC) is deteriorated with neuromuscular fatigue, altitude or sleep deprivation induced by a mountain ultra-marathon (MUM). Several regulatory mechanisms have also been reported during this type of event and the changes in PC at different points of MUM remain unknown. The purpose of this study was to investigate the time course of PC during an extreme MUM.

Hamstring Architectural and Functional Adaptations Following Long vs. Short Muscle Length Eccentric Training.

Most common preventive eccentric-based exercises, such as Nordic hamstring do not include any hip flexion. So, the elongation stress reached is lower than during the late swing phase of sprinting. The aim of this study was to assess the evolution of hamstring architectural (fascicle length and pennation angle) and functional (concentric and eccentric optimum angles and concentric and eccentric peak torques) parameters following a 3-week eccentric resistance program performed at long (LML) vs.

Running Mechanics During the World's Most Challenging Mountain Ultramarathon.

The aim of study was to examine the effects of the world's most challenging mountain ultramarathon (Tor des Géants [TdG]) on running mechanics. Mechanical measurements were undertaken in male runners (n = 16) and a control group (n = 8) before (PRE), during (MID), and after (POST) the TdG. Contact (tc) and aerial (ta) times, step frequency (f), and running velocity (v) were sampled.

Influence on Strength and Flexibility of a Swing Phase-Specific Hamstring Eccentric Program in Sprinters' General Preparation.

Hamstring injuries are common in sprinters and mainly occur during the terminal swing phase. Eccentric training has been shown to reduce hamstring injury rate by improving several risk factors. The aim of this study was to test the hypothesis that an additional swing phase-specific hamstring eccentric training in well-trained sprinters performed at the commencement of the winter preparation is more efficient to improve strength, ratio, optimum angle, and flexibility than a similar program without hamstring eccentric exercises.

Validity and reliability of maximal-strength assessment of knee flexors and extensors using elastic bands.

Context: In the field of sport rehabilitation, an easy, valid, and reliable assessment of maximal strength is crucial for efficient muscle rehabilitation. Classically, it is performed on fitness equipment that is not necessary available in the field. Thera-Band has developed elastic bands with different resistances depending on the color of the band and on the percentage of its stretch.

Alterations in postural control during the world's most challenging mountain ultra-marathon.

We investigated postural control (PC) effects of a mountain ultra-marathon (MUM): a 330-km trail run with 24000 m of positive and negative change in elevation. PC was assessed prior to (PRE), during (MID) and after (POST) the MUM in experienced ultra-marathon runners (n = 18; finish time = 126 ± 16 h) and in a control group (n = 8) with a similar level of sleep deprivation. Subjects were instructed to stand upright on a posturographic platform over a period of 51.

Conceptual framework for strengthening exercises to prevent hamstring strains.

High-speed running accounts for the majority of hamstring strains in many sports. The terminal swing phase is believed to be the most hazardous as the hamstrings are undergoing an active lengthening contraction in a long muscle length position. Prevention-based strength training mainly focuses on eccentric exercises.

Effect of hip flexion angle on hamstring optimum length after a single set of concentric contractions.

The eccentric contraction mode was proposed to be the primary stimulus for optimum angle (angle at which peak torque occurs) shift. However, the training range of motion (or muscle excursion range) could be a stimulus as important. The aim of this study was to assess the influence of the training range of motion stimulus on the hamstring optimum length.

Changes in running mechanics and spring-mass behaviour induced by a 5-hour hilly running bout.

The aim of this study was to investigate changes in running mechanics and spring-mass behaviour with fatigue induced by 5-hour hilly running (5HHR). Running mechanics were measured pre- and post-5HHR at 10, 12 and 14 km · h(-1) on an instrumented treadmill in eight ultramarathon runners, and sampled at 1000 Hz for 10 consecutive steps. Contact (t(c) ) and aerial (t(a) ) times were determined from ground reaction force (GRF) signals and used to compute step frequency (f).

Influence of hip-flexion angle on hamstrings isokinetic activity in sprinters.

Context: Hamstrings strains are common and debilitating injuries in many sports. Most hamstrings exercises are performed at an inadequately low hip-flexion angle because this angle surpasses 70° at the end of the sprinting leg's swing phase, when most injuries occur.

Objective: To evaluate the influence of various hip-flexion angles on peak torques of knee flexors in isometric, concentric, and eccentric contractions and on the hamstrings-to-quadriceps ratio.

Passive knee-extension test to measure hamstring tightness: influence of gravity correction.

Context: A passive knee-extension test has been shown to be a reliable method of assessing hamstring tightness, but this method does not take into account the potential effect of gravity on the tested leg.

Objective: To compare an original passive knee-extension test with 2 adapted methods including gravity's effect on the lower leg.

Design: Repeated measures.