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Masatoshi Nakamura, Tome Ikezoe, Hiroki Umegaki, Takuya Kobayashi, Satoru Nishishita and Noriaki Ichihashi

Context:

Static stretching (SS) is commonly performed in a warm-up routine to increase joint range of motion (ROM) and to decrease muscle stiffness. However, the time course of changes in ankle-dorsiflexion (DF) ROM and muscle stiffness during a routine SS program is unclear.

Objective:

To investigate changes in ankle-DF ROM, passive torque at DF ROM, and muscle stiffness during a routine SS program performed 3 times weekly for 4 wk.

Design:

A quasi-randomized controlled-trial design.

Participants:

The subjects comprised 24 male volunteers (age 23.8 ± 2.3 y, height 172.0 ± 4.3 cm, body mass 63.1 ± 4.5 kg) randomly assigned to either a group performing a 4-wk stretching program (SS group) or a control group.

Main Outcome Measures:

DF ROM, passive torque, and muscle stiffness were measured during passive ankle dorsiflexion in both groups using a dynamometer and ultrasonography once weekly during the 4-wk intervention period.

Results:

In the SS group, DF ROM and passive torque at DF ROM significantly increased after 2, 3, and 4 wk compared with the initial measurements. Muscle stiffness also decreased significantly after 3 and 4 wk in the SS group. However, there were no significant changes in the control group.

Conclusions:

Based on these results, the SS program effectively increased DF ROM and decreased muscle stiffness. Furthermore, an SS program of more than 2 wk duration effectively increased DF ROM and changed the stretch tolerance, and an SS program more than 3 wk in duration effectively decreased muscle stiffness.

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Douglas Mann and Charles Whedon

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K.A. Paul Edman

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Vassilis Gerodimos, Andreas Zafeiridis, Stefanos Perkos, Konstantina Dipla, Vassiliki Manou and Spiros Kellis

This study examined from childhood to adulthood: (1) the effects of countermovement (use of stretch-shortening cycle-SSC) and arm-swing (AS) on vertical jumping (VJ) performance and (2) the ability to use the SSC and AS during VJ. Male basketball players (n = 106) were divided according to their age into: children (12.0 ± 0.23), young adolescents (14.5 ± 0.41), old adolescents (16.9 ± 0.27), and adults (21.9 ± 0.32). Each participant executed three maximal squat jumps (SJ), countermovement jumps without arms (CMJ) and with arms (CMJA). The contribution of SSC and AS was calculated by the augmentation (difference and percent change) in performance between CMJ and SJ, and CMJA and CMJ, respectively. CMJA performance was significantly (p < .05) higher than CMJ and SJ, and CMJ was higher than SJ within all age-groups. There were no significant differences (p > .05) among children, young and old adolescents, and adults in the percent contribution of SSC and AS to VJ performance. The variability in the contribution of SSC and AS to VJ performance was about twofold higher in children vs. adults. It appears that the ability to use the SSC and AS is not affected by the maturation process in males, trained in basketball.

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Jacqueline Vieira de Castro, Karina Costa Machado, Kelly Scaramussa and João Luiz Ellera Gomes

Context:

After years of focusing on the management of anterior cruciate ligament (ACL) injuries, the most common soccer-related injuries, the orthopedic community has concluded that soccer players have a wide range of variation in joint biomechanics and has thus started to focus research efforts on the morphological factors that might contribute to ACL trauma. One such factor is decreased hip-rotation range of motion (ROM), which may be due to compensatory musculoskeletal changes occurring in response to longstanding soccer practice since childhood.

Objective:

This study sought to assess decreased hip rotation and the influence of stretching exercises on the behavior of the hip joint in players of the youth soccer categories of a Brazilian soccer team.

Design:

Randomized clinical trial.

Setting:

University hospital.

Patients:

262 male soccer players.

Interventions:

Subjects were randomly allocated into 2 groups—control or a stretching program.

Main Outcome Measures:

Subjects were reassessed after 12 wk.

Results:

The findings suggest that hip-rotation ROM decreases over the years in soccer players. In the study sample, adherence to a stretching program improved only external hip-rotation ROM in the nondominant limb.

Conclusion:

Playing soccer can restrict rotation ROM of the hip, and adherence to stretching exercises may decrease the harmful effects on the hip joints.

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Christine Stopka

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Maxwell Ruby, Chris P. Repka and Paul J. Arciero

Background:

Yoga/Stretching (YS) and functional resistance (FR) training are popular exercise routines. A protein-pacing (PP) diet is a common dietary regimen. Thus, we assessed the effectiveness of a PP diet alone and in combination with either YS or FR to improve body composition and cardiometabolic health.

Methods:

Twenty-seven overweight women (age = 43.2 ± 4.6 years) were randomized into 3 groups: yoga (YS, n = 8) or resistance (FR, n = 10) training (3 days/week) in conjunction with PP diet (50% carbohydrate, 25% protein, and 25% fat) or PP diet-only (PP, n = 9) throughout 12-week study. PP maintained preexisting levels of physical activity. Body weight (BW), total (BF) and abdominal (ABF) body fat, waist circumference (WC), plasma biomarkers, and aerobic fitness (VO2) were measured at baseline and 12 weeks.

Results:

WC and total cholesterol improved in all groups, whereas glycemia tended to improve (P = .06) in S. BF, ABF, and VO2 increased significantly in YS and FR (P < .05). Feelings of vigor increased in YS and tension decreased in FR (P < .05).

Conclusions:

YS training tended to decrease blood glucose compared with FR and PP and is equally effective at enhancing body composition, and aerobic fitness in overweight women providing a strong rationale for further research on YS training.

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John G. Williams, Roger G. Eston and Clare Stretch

This study examined the ability of 40 children (20 boys and 20 girls), ages 11 to 14 years, to regulate the intensity of their effort using perceived effort ratings during cycling. The Borg Rating of Perceived Exertion 6 to 20 Scale was learned and used as a perceptual frame of reference. Maximal oxygen uptake and power output were predicted from telemetered heart rate data collected during a submaximal graded exercise test. Subjects were then fully familiarized with the RPE scale and attended three consecutive sessions of cycling during which they adjusted the workloads themselves so as to produce effort intensities for scale ratings of 9 (very light), 13 (somewhat hard), and 17 (very hard). Heart rates were sampled during the final half minute of each session and the data were submitted to a mixed factorial analysis of variance. This showed highly significant differences (p<.001) between the three RPE levels but no significant effects for age, gender, or trials. It was concluded that the RPE is readily learned by older children and adolescents and is a potentially useful frame of reference when self-regulating effort intensity during vigorous exercise.