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Olfa Turki, Wissem Dhahbi, Johnny Padulo, Riadh Khalifa, Sana Ridène, Khaled Alamri, Mirjana Milić, Sabri Gueid and Karim Chamari

research identified substantial improvements in explosive activities (ie, sprinting, jumping, and agility) using various warm-up strategies, few studies have focused on team sports. 4 , 5 Dynamic stretching (DS) warm-ups must be designed for the specific needs of both the player and the sporting activity

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Natália Barros Beltrão, Camila Ximenes Santos, Valéria Mayaly Alves de Oliveira, André Luiz Torres Pirauá, David Behm, Ana Carolina Rodarti Pitangui and Rodrigo Cappato de Araújo

Stretching intensity is an important variable that can be manipulated with flexibility training. The degree of muscle-tendon elongation is controlled by the individual’s subjective assessment of stretch tolerance based on the degree of pain or discomfort. 1 Although stretching intensity can

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Jeni R. McNeal and William A. Sands

Several studies utilizing adult subjects have indicated that static stretching may reduce subsequent strength and power production, possibly for as long as an hour following the stretch. This observation has not been evaluated in children, nor in athletes accustomed to performing static stretches during strength/power type training sessions. The purpose of this investigation was to determine if an acute bout of passive, static stretching of the lower extremity would affect jumping performance in a group of young, female gymnasts. Thirteen competitive gymnasts (age 13.3 − 2.6 yrs) performed drop jumps under two conditions: immediately following stretching and without prior stretching. The jumps were performed on separate days. The conditions were randomly ordered among the subjects. Time in the air (AIR) and ground contact time (CT) were measured during the drop jumps using a timing mat. Three different stretches of the lower extremity were conducted on each gymnast twice, each stretch being held for 30 seconds. Following the stretching condition, AIR was significantly reduced (.44 vs .46 sec, p < .001), while CT was not different (.130 for both conditions, p > .05). This study demonstrates that children’s lower extremity power is reduced when the performance immediately follows passive, static stretching, even in children accustomed to static stretching during training sessions involving explosive power.

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Kristian J. Hill, Kendall P. Robinson, Jennifer W. Cuchna and Matthew C. Hoch

Clinical Scenario:

Increasing hamstring flexibility through clinical stretching interventions may be an effective means to prevent hamstring injuries. However the most effective method to increase hamstring flexibility has yet to be determined.

Clinical Question:

For a healthy individual, are proprioceptive neuromuscular facilitation (PNF) stretching programs more effective in immediately improving hamstring flexibility when compared with static stretching programs?

Summary of Key Findings:

A thorough literature search returned 195 possible studies; 5 studies met the inclusion criteria and were included. Current evidence supports the use of PNF stretching or static stretching programs for increasing hamstring flexibility. However, neither program demonstrated superior effectiveness when examining immediate increases in hamstring flexibility.

Clinical Bottom Line:

There were consistent findings from multiple low-quality studies that indicate there is no difference in the immediate improvements in hamstring flexibility when comparing PNF stretching programs to static stretching programs in physically active adults.

Strength of Recommendation:

Grade B evidence exists that PNF and static stretching programs equally increase hamstring flexibility immediately following the stretching program.

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Matthew J. Hussey, Alex E. Boron-Magulick, Tamara C. Valovich McLeod and Cailee E. Welch Bacon

measures (eg, no intervention, static self-stretching measures, and TheraBand warm-up measures), study procedures, and ROM measurements (eg, internal rotation, horizontal adduction). 1 – 3 Current research identifies a few soft tissue therapy techniques for treating pain and increasing ROM including

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Kosuke Fujita, Masatoshi Nakamura, Hiroki Umegaki, Takuya Kobayashi, Satoru Nishishita, Hiroki Tanaka, Satoko Ibuki and Noriaki Ichihashi

shown the combination of heat modalities and stretching to be superior to static stretching only for increasing joint ROM but not for lowering the passive stiffness of the muscle at the same joint angle. 8 On the other hand, only a few studies have evaluated the effect of physical activity in improving

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Stéphane Perrey, Guillaume Millet, Robin Candau and Jean-Denis Rouillon

The purpose of this study was to examine the effects of speed on the stretch-shortening cycle (SSC) behavior during roller ski skating. Ten highly skilled male cross-country skiers roller skied at 4.56, 5.33 m · s–1 and maximal speed using the V2-alternate technique on a flat terrain. Knee and ankle joint kinematics, and EMG of the vastus lateralis (VL) and gastrocnemius lateralis (GL) muscles were recorded during the last 40 s of each bout of roller skiing. Maximal speed was associated with increases in cycle rate combined with decreases in cycle length. For VL, no significant differences were observed for the integrated EMG eccentric-to-concentric ratio (iEMG Ecc/Conc) and for the stretching velocity over the range of speeds. For GL, stretching velocity and iEMG Ecc/Conc were significantly greater at maximal speed. The analysis of GL EMG activity suggests that speed improved GL stiffness so that more elastic energy was stored, a better force transmission occurred, and coupling time decreased. These findings suggest that the efficiency of roller ski skating locomotion may be increased with speed through a better use of the stretch-shortening cycle pattern in the ankle extensors.

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Richard G. Mynark and David M. Koceja

The spinal stretch reflex consists of a relatively simple neuronal network. The Ia afferent fiber of the muscle spindle communicates to the alpha motoneuron via a single synapse. This basic pathway has been studied extensively over the past century, yet considerable information continues to emerge concerning the manner in which this pathway adapts to aging. It is well accepted that the amplitude of the spinal stretch reflex declines with normal aging, and it is intuitively agreed that these changes have a detrimental impact on the motor output of aging individuals. Understanding the changes observed in the spinal stretch reflex pathway due to aging requires a recognition of the changes that can occur in each component of this spinal network. This review will address these changes by following the spinal stretch reflex from initiation to completion. The components that result in the sensory input to the motoneuron will be covered first, followed by a review of the physiological changes that can occur to the motoneuron soma that can affect the processing of the sensory input. The output of the motoneuron encompasses the remaining components from the motor axon itself, to the neuromuscular junction, and then to the characteristic changes in the muscle. Finally, the functional effect that these changes have on the reflex as a fundamental motor behavior will be addressed, especially in terms of its impact on posture and balance.

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Christine Stopka, Kevin Morley, Ronald Siders, Josh Schuette, Ashley Houck and Yul Gilmet

Objective/Context:

To examine the effects of static and proprioceptive neuromuscular facilitation (PNF) stretching in Special Olympics athletes and their coaches on sit-and-reach performance.

Design/Participants:

Repeated-measures ANOVA with Scheffé post hoc analyses on 2 groups: Special Olympics athletes (n = 18, mean age = 15.7) and their coaches without mental retardation (n = 44, mean age = 22.2).

Intervention/Outcome Measures:

Stretching performance was measured in centimeters using a sit-and-reach flexibility box, examining 2 series of 3 stretches. For both groups, the first set of 3 stretches was performed in the following order: baseline, static, PNF. Three to 4 weeks later, the order of the stretches was reversed: baseline, PNF, static.

Results:

PNF stretching improved performance regardless of stretching order after baseline and static measures. Static stretching improved performance only from baseline.

Conclusions:

Individuals of various ages and cognitive abilities can apparently perform and benefit from PNF stretching.

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Jason Brandenburg, William A. Pitney, Paul E. Luebbers, Arun Veera and Alicja Czajka

Purpose:

To examine the acute effects of static stretching on countermovement vertical-jump (CMVJ) ability and monitor the time course of any stretch-induced changes.

Methods:

Once familiarized, 16 experienced jumpers completed 2 testing sessions in a randomized order. Each session consisted of a general warm-up, a pretreatment CMVJ assessment, a treatment, and multiple posttreatment CMVJ assessments. One treatment included lower-body static stretching, and the second treatment, involving no stretching, was the control. Posttreatment CMVJ measures occurred immediately, 3, 6, 12, and 24 minutes posttreatment. Stretching consisted of 3 static-stretching exercises, with each exercise repeated 3 times and each repetition held for 30 s.

Results:

Prestretch CMVJ height equaled 47.1 (± 9.7) cm. CMVJ height immediately poststretch was 45.7 (± 9.2) cm, and it remained depressed during the 24-min follow-up period. Pre-no-stretch CMVJ height was 48.4 (± 9.8) cm, whereas immediately post-no-stretch CMVJ height equaled 46.8 (± 9.5) cm, and as in the stretch treatment, post-no-stretch CMVJ height remained lower than pre-no-stretch values. Although there was a significant main effect of time (P = .005), indicating that CMVJ was lower and remained impaired after both treatments, no significant interaction effect (P = .749) was observed.

Conclusion:

In comparison with the no-activity control, static stretching resulted in similar reductions in CMVJ ability when examined over the same time course, so athletes preparing for CMVJ should avoid periods of inactivity, as well as static stretching.