Kinetic variables of the lower limb joint that affect the drop jump index at different drop heights.

Background: The drop jump index evaluates power exertion in the lower limb stretch-shortening cycle. In addition, the ability to exert power during the stretch-shortening cycle can be evaluated in detail by combining the drop jump index with the kinetic variables of the three lower limb joints. The purpose of this study was to determine the kinetic variables of the three lower limb joints during takeoff that affect the drop jump index of a drop jump from different drop heights.

Compensatory Kinetics During the Side-Hop Test in Individuals With Chronic Ankle Instability.

Context: Individuals with chronic ankle instability (CAI) exhibit altered movement strategies during side-cutting tasks. However, no researchers have assessed how altered movement strategies affect cutting performance.

Objective: To investigate compensatory strategies in the side-hop test (SHT), with a focus on the entire lower extremity, among individuals with CAI.

Elite Rugby Players have Unique Morphological Characteristics of the Hamstrings and Quadriceps Femoris Muscles According to their Playing Positions.

Rugby is a popular sport requiring high-intensity and maximal speed actions. Numerous studies have demonstrated that physical performance variables, such as strength, sprinting, and jumping, are different between the forwards and backs. However, there is little information about muscle morphological characteristics specific for each rugby playing position.

Sub-elite sprinters and rugby players possess different morphological characteristics of the individual hamstrings and quadriceps muscles.

Numerous studies have clarified that sprinters possess unique morphological characteristics of the thigh muscles compared with non-athletes. However, little evidence is available regarding the morphological differences between sprinters and rugby players. This study aimed to examine the morphological differences in the individual hamstrings and quadriceps femoris muscles between sub-elite sprinters and rugby players.

Muscle- and Region-Specific Associations Between Muscle Size and Muscular Strength During Hip Extension and Knee Flexion in the Hamstrings.

Context: Strength deficits of the hamstrings following sports injuries decrease athletic performance and increase the risk of injury recurrence. Previous studies have shown a high correlation between the muscular strength during hip-extension and knee-flexion and total muscle size of the hamstrings. However, it remains unclear which region of the individual hamstring muscles is closely associated with muscular strength.

Sprinting kinematics and inter-limb coordination patterns at varying slope inclinations.

Uphill training is applied to induce specific overload on the musculoskeletal system to improve sprinting mechanics. This study aimed to identify unique kinematic features of uphill sprinting at different slopes and to suggest practical implications based on comparisons we early stance phase. At take-off, steeper slopes induced significantly more extended joint angles and higher ROMs during the late stance phase.

Effect of Knee Joint Angle on Regional Hamstrings Activation During Isometric Knee-Flexion Exercise.

Context: Each hamstring muscle is subdivided into several regions by multiple motor nerve branches, which implies each region has different muscle activation properties. However, little is known about the muscle activation of each region with a change in the knee joint angle. Understanding of regional activation of the hamstrings could be helpful for designing rehabilitation and training programs targeted at strengthening a specific region.

Three-dimensional CoM energetics, pelvis and lower limbs joint kinematics of uphill treadmill running at high speed.

The purpose of this study was to investigate the effects of slope on three-dimensional running kinematics at high speed. Thirteen male sprinters ran at high speed (7.5 m/s) on a motorised treadmill in each a level and a 5.

Effects of work-matched moderate- and high-intensity warm-up on power output during 2-min supramaximal cycling.

We tested the hypothesis that compared with a moderate-intensity warm-up, a work-matched high-intensity warm-up improves final-sprint power output during the last 30 s of a 120-s supramaximal exercise that mimics the final sprint during events such as the 800-m run, 1,500-m speed skate, or Keirin (cycling race). Nine active young males performed a 120-s supramaximal cycling exercise consisting of 90 s of constant-workload cycling at a workload that corresponds to 110% peak oxygen uptake (VO) followed by 30 s of maximal cycling. This exercise was preceded by 1) no warm-up (control), 2) a 10-min cycling warm-up at a workload of 40% VO (moderate-intensity), or 3) a 5-min cycling warm-up at a workload of 80% VO (high-intensity).

Effects of work-matched supramaximal intermittent vs. submaximal constant-workload warm-up on all-out effort power output at the end of 2 minutes of maximal cycling.

We tested the hypothesis that work-matched supramaximal intermittent warm-up improves final-sprint power output to a greater degree than submaximal constant-intensity warm-up during the last 30 s of a 120-s supramaximal exercise simulating the final sprint during sports events lasting approximately 2 min. Ten male middle-distance runners performed a 120-s supramaximal cycling exercise consisting of 90 s of constant-workload cycling at a workload corresponding to 110% maximal oxygen uptake (VO) followed by 30 s of maximal-effort cycling. This exercise was preceded by 1) no warm-up (Control), 2) a constant-workload cycling warm-up at a workload of 60%VO for 6 min and 40 s, or 3) a supramaximal intermittent cycling warm-up for 6 min and 40 s consisting of 5 sets of 65 s of cycling at a workload of 46%VO + 15 s of supramaximal cycling at a workload of 120%VO.

Effect of voluntary hypocapnic hyperventilation or moderate hypoxia on metabolic and heart rate responses during high-intensity intermittent exercise.

Purpose: To investigate the effect of voluntary hypocapnic hyperventilation or moderate hypoxia on metabolic and heart rate responses during high-intensity intermittent exercise.

Methods: Ten males performed three 30-s bouts of high-intensity cycling [Ex1 and Ex2: constant-workload at 80% of the power output in the Wingate anaerobic test (WAnT), Ex3: WAnT] interspaced with 4-min recovery periods under normoxic (Control), hypocapnic or hypoxic (2500 m) conditions. Hypocapnia was developed through voluntary hyperventilation for 20 min prior to Ex1 and during each recovery period.

Spatial Awareness is Related to Moderate Intensity Running during a Collegiate Rugby Match.

The purpose of the present study was to evaluate the relationship between spatial awareness, agility, and distance covered in global positioning system (GPS) derived velocity zone classifications during a collegiate rugby match. Twelve American collegiate rugby union players (mean±SD; age: 21.2±1.

Isometric Mid-Thigh Pull Correlates With Strength, Sprint, and Agility Performance in Collegiate Rugby Union Players.

Wang, R, Hoffman, JR, Tanigawa, S, Miramonti, AA, La Monica, MB, Beyer, KS, Church, DD, Fukuda, DH, and Stout, JR. Isometric mid-thigh pull correlates with strength, sprint, and agility performance in collegiate rugby union players. J Strength Cond Res 30(11): 3051-3056, 2016-The purpose of this investigation was to examine the relationships between isometric mid-thigh pull (IMTP) force and strength, sprint, and agility performance in collegiate rugby union players.

Physical Differences Between Forwards and Backs in American Collegiate Rugby Players.

La Monica, MB, Fukuda, DH, Miramonti, AA, Beyer, KS, Hoffman, MW, Boone, CH, Tanigawa, S, Wang, R, Church, DD, Stout, JR, and Hoffman, JR. Physical differences between forwards and backs in American collegiate rugby players. J Strength Cond Res 30(9): 2382-2391, 2016-This study examined the anthropometric and physical performance differences between forwards and backs in a championship-level American male collegiate rugby team.