Effect of High-Intensity With Short-Duration Re-Warm-Up on Subsequent Performance in a Cold Environment.

Yamashita, Y and Umemura, Y. Effect of high-intensity with short-duration re-warm up on subsequent performance in a cold environment. J Strength Cond Res 38(6): e280-e287, 2024-The aim of this study was to investigate the effect of high-intensity, short-duration re-warm-up (RW) during half time (HT) on subsequent performance in a cold environment.

Addition of In-Play Cooling Breaks During Intermittent Exercise While Wearing Lacrosse Uniforms in The Heat Attenuates Increases in Rectal Temperature.

To reduce the risk of heat-related illness, appropriate body cooling strategies are needed during men's lacrosse competitions in hot-humid environments. The current study investigated whether additional in-play cooling breaks would attenuate the core (rectal) body temperature rise during exercise designed to mimic the activity patterns of a men's lacrosse match while wearing uniform in hot-humid environments. In randomized and counterbalanced order, ten physically active men completed two experimental trials comprising four quarters of 15-min intermittent cycling exercises separated by a 10-min simulated half-time break and two 2-min quarter breaks in a climate chamber (35°C, 50% relative humidity).

Effect of High-Intensity, Intermittent, Short-Duration Re-Warming up on Cycling Sprint Performance.

The aim of this study was to investigate the effects of warming up again during half-time (i.e., re-warm up [RW]) with high-intensity, intermittent, short-duration exercise on cycling sprint performance.

Effects of Half-Time Cooling Using a Fan with Skin Wetting on Thermal Response During Intermittent Cycling Exercise in the Heat.

The present study investigated the effects of half-time (HT) break cooling using a fan and damp sponge on physiological and perceptual responses during the 2 half of a repeated-sprint exercise in a hot environment. Eight physically active men performed a familiarization trial and two experimental trials of a 2×30-min intermittent cycling exercise protocol with a 15-min HT break in hot conditions (35°C, 50% relative humidity). Two experimental trials were conducted in random order: skin wetting with a fan (FAN ) and no cooling (CON).

Jump Exercise and Food Restriction on Bone Parameters in Young Female Rats.

We examined the effect of jump exercise on bone parameters in young female rats under food restriction. Seven-week-old female rats were divided into four groups: a sedentary and ad libitum feeding group (n = 10), a jump exercise and ad libitum feeding group (n = 9), a sedentary and 30% food restriction group (n = 9), and a jump exercise and 30% food restriction group (n = 10). The jump groups jumped 20 times/day, 5 times/week.

[The effects of jumping exercise on bones.].

Strain rate and strain magnitude are important factors when considering osteogenic response to the bone strain imposed by mechanical stress. Jumping is a high-impact exercise that includes these factors. Ten to twenty jumping repetitions per day can increase bone mass and strength.

Past sporting activity during growth induces greater bone mineral content and enhances bone geometry in young men and women.

We aimed to determine the effect of past sporting activity on bone mineral content (BMC), areal bone mineral density (aBMD) in the lumbar spine and proximal femur, and bone geometry of the mid femur in young men and women. We assessed 142 subjects, comprising 79 young men (21.2 ± 0.

Local architecture of the vastus intermedius is a better predictor of knee extension force than that of the other quadriceps femoris muscle heads.

The purpose of this study was to determine whether the muscle architecture of each head of the quadriceps femoris (QF) at multiple regions can be used to predict knee extension force. Muscle thickness and pennation angle were measured using sonographic images from multiple regions on each muscle of the QF with the knee flexed to 90°. The fascicle lengths of the rectus femoris (RF), vastus lateralis (VL) and vastus intermedius (VI) muscles were estimated based on sonographic images taken along the length of the thigh.

Stretching-induced deficit of maximal isometric torque is restored within 10 minutes.

The purpose of this study was to clarify the time course of the stretching-induced decrease in maximal isometric plantar flexion torque. Nineteen women participated in 2 randomly ordered experimental trials: static 5-minute stretching or control with no stretching. The participants performed isometric maximal voluntary contractions (MVCs) of the right plantar flexor muscles, whereas electromyographic (EMG) amplitude (root mean square) was calculated for the medial and lateral gastrocnemius muscles.

High-impact exercise frequency per week or day for osteogenic response in rats.

The frequency per week or day of high-impact, low-repetition jump exercise for osteogenic response was assessed by two experiments. In the first experiment, 48 11-week-old rats were randomly divided into five groups: a sedentary control (W0: n = 8), one exercise session per week (W1: n = 10), three exercise sessions per week (W3: n = 10), five exercise sessions per week (W5: n = 10), and seven exercise sessions per week (W7: n = 10). In the second experiment, 30 11-week-old rats were randomly divided into three groups: a sedentary control (D0: n = 10), one exercise session per day (D1: n = 10), and two exercise sessions per day (D2: n = 10).

Bones benefits gained by jump training are preserved after detraining in young and adult rats.

We investigated the osteogenic responses to jump training and subsequent detraining in young and adult male rats to test the following hypotheses: 1) jump training has skeletal benefits; 2) these skeletal benefits are preserved with subsequent detraining throughout bone morphometric changes; and 3) there are no differences between young and adult rats during detraining in terms of the maintenance of exercise-induced changes. Twelve-week-old (young) and 44-wk-old (adult) rats were divided into the following four groups: young-sedentary, young-exercised, adult-sedentary, and adult-exercised. The exercised groups performed jump training (height = 40 cm, 10 jumps/day, 5 days/wk) for 8 wk followed by 24 wk of being sedentary.

Effects of low-repetition jump exercise on osteogenic response in rats.

Jump exercise in rats creates high-impact loading on lower limbs and results in the promotion of osteogenesis. Although we clarified that a few loadings per day could increase bone mass and strength within 8 weeks, we did not observe an osteogenic response at the onset of the training period. The purpose of this study was to clarify whether the bone formation rate measured by the double-label immunofluorescence method increases with a few loadings for a short period.

Effects of jump training on bone are preserved after detraining, regardless of estrogen secretion state in rats.

We investigated whether the effects of jump training on bone are preserved after a detraining period in female normal and estrogen-deficient rats. Forty-four 11-wk-old Wistar rats were divided into the following four groups: sham sedentary (n = 12), sham exercised (n = 11), ovariectomized sedentary (n = 10), and ovariectomized exercised (n = 11). An 8-wk exercise period was introduced in which the rats in the exercised groups were jumped 10 times/day, 5 days/wk.

Effect of low-repetition jump training on bone mineral density in young women.

The hypothesis of the present study was that low-repetition and high-impact training of 10 maximum vertical jumps/day, 3 times/wk would be effective for improving bone mineral density (BMD) in ordinary young women. Thirty-six female college students, with mean age, height, and weight of 20.7+/-0.

High-impact exercise strengthens bone in osteopenic ovariectomized rats with the same outcome as Sham rats.

The effect of jump exercise on middle-aged osteopenic rats was investigated. Forty-two 9-mo-old female rats were either sham-operated (Sham) or ovariectomized (OVX). Three months after surgery, the rats were divided into the following groups: Sham sedentary, Sham exercised, OVX sedentary, and OVX exercised.

Effects of intervals between jumps or bouts on osteogenic response to loading.

Prolonged loading repetitions can diminish the mechanosensitivity of bones, and increased intervals between loading might restore sensitivity. This study was designed to investigate the effects of intervals between loadings or bouts on osteogenic response. Forty female Fisher 344 rats aged 5 wk were divided into a control group and three exercise groups: 20 jumps in a single bout with a 3-s (S3) or 30-s (S30) jump interval, or 20 jumps in 2 bouts (10 x 2) separated by a 6-h interval with a 3-s jump interval (D3).

A time course of bone response to jump exercise in C57BL/6J mice.

Exercise, by way of mechanical loading, provides a physiological stimulus to which bone tissue adapts by increased bone formation. The mechanical stimulus due to physical activity depends on both the magnitude and the duration of the exercise. Earlier studies have demonstrated that jump training for 4 weeks produces a significant bone formation response in C57BL/6J mice.