Acute effects of static stretching, proprioceptive neuromuscular facilitation stretching, and maximum voluntary contractions on explosive force production and jumping performance
- Authors: Young, Warren , Elliott, Simon
- Date: 2001
- Type: Text , Journal article
- Relation: Research Quarterly for Exercise and Sport Vol. 72, no. 3 (2001), p. 273-279
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- Description: 2003003761
Resistance training for short sprints and maximum-speed sprints
- Authors: Young, Warren , Benton, Dean , Duthie, Grant , Pryor, John
- Date: 2001
- Type: Text , Journal article
- Relation: Strength and Conditioning Journal Vol. 23, no. 2 (2001), p. 7-13
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Specificity of sprint and agility training methods
- Authors: Young, Warren , McDowell, Mark , Scarlett, Bentley
- Date: 2001
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 15, no. 3 (2001), p. 315-319
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- Description: The purpose of this study was to determine if straight sprint training transferred to agility performance tests that involved various change-of-direction complexities and if agility training transferred to straight sprinting speed. Thirty-six males were tested on a 30-m straight sprint and 6 agility tests with 2-5 changes of direction at various angles. The subjects participated in 2 training sessions per week for 6 weeks using 20-40-m straight sprints (speed) or 20-40-m change-of-direction sprints (3-5 changes of 100°) (agility). After the training period, the subjects were retested, and the speed training resulted in significant improvements (p < 0.05) in straight sprinting speed but limited gains in the agility tests. Generally, the more complex the agility task, the less the transfer from the speed training to the agility task. Conversely, the agility training resulted in significant improvements in the change-of-direction tests (p < 0.05) but no significant improvement (p > 0.05) in straight sprint performance. We concluded that straight speed and agility training methods are specific and produce limited transfer to the other. These findings have implications for the design of speed and agility training and testing protocols.
- Description: 2003003767
Validity of double and single leg vertical jumps as tests of leg extensor muscle function
- Authors: Young, Warren , MacDonald, Chris J. , Flowers, Michelle
- Date: 2001
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 15, no. 1 (2001), p. 6-11
- Full Text: false
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- Description: The purpose of this research was to determine if 5 weeks of resistance training for the shoulder and hip flexor muscles produces improvements in vertical jumping (VJ) performance. Twenty-eight men were assessed on tests of shoulder power, leg extensor muscle function, and VJ performance using jumps performed from a standing position, a 3-stride run-up, and double- and single-leg takeoffs. A shoulder and hip flexor training group (n = 14) improved significantly more than a nontraining control group (n = 12) in shoulder power and 2 VJ performance tests, but not in the tests of leg extensor muscle function. It was concluded that the arm swing and free-leg drive significantly influence VJ performance and, therefore, VJ tests are not valid for assessment of leg extensor muscle function.
- Description: 2003003764
Is muscle power related to running speed with changes of direction?
- Authors: Young, Warren , James, R. , Montgomery, Iain
- Date: 2002
- Type: Text , Journal article
- Relation: Journal of Sports Medicine and Physical Fitness Vol. 42, no. 3 (Sep 2002), p. 282-288
- Full Text: false
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- Description: Background. The purpose of this study was to identify the relationships between leg muscle power and sprinting speed with changes of direction. Methods. Experimental design: the study was designed to describe relationships between physical qualities and a component of sports performance: Setting: testing was conducted in an indoor sports hall and a biomechanics laboratory. Participants: 15 male participants were required to be free of injury and have recent experience competing in sports involving sprints with changes of direction. Measures: subjects were timed in 8 m sprints in a straight line and with various changes of direction. They were also tested for bilateral and unilateral leg extensor muscle concentric power output by an isokinetic squat and reactive strength by a drop jump. Results. The correlations between concentric power and straight sprinting speed were non-significant whereas the relationships between reactive strength and straight speed were statistically significant. Correlations between muscle power and speed while changing direction were generally low and non-significant for concentric leg power with some moderate and significant (p<0.05) coefficients found for reactive strength. The participants who turned faster to one side tended to have a reactive strength dominance in the leg responsible for the push-off action. Conclusions. The relationships between leg muscle power and change-of-direction speed were not consistent. Reactive strength as measured by the drop jump appears to have some importance for lateral change-of-direction speed, possibly because of similar push-off actions. It was concluded that reactive strength of the leg extensor muscles has some importance in change-of-direction performance but the other technical and perceptual factors than influence agility performance should also be considered.
- Description: 2003000213
Should static stretching be used during a warm-up for strength and power activities?
- Authors: Young, Warren , Behm, David
- Date: 2002
- Type: Text , Journal article
- Relation: Strength and Conditioning Journal Vol. 24, no. 6 (2002), p. 33-37
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- Description: 2003000236
The acute effects of heavy loads on jump squat performance: An evaluation of the complex and contrast methods of power development
- Authors: Duthie, Grant , Young, Warren , Aitken, David
- Date: 2002
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 16, no. 4 (2002), p. 530-538
- Full Text: false
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- Description: The purpose of this investigation was to examine power performance in jump squats when using the complex and contrast training methods. Eleven (n = 11) women participated in a familiarization session and in three randomly ordered testing sessions. One session involved completing sets of power exercises (jump squats) before sets of half squats (traditional method). The second session involved sets of half squats before sets of jump squats (complex method). A third session involved the alternation of sets of half squats and jump squats (contrast method). No significant difference in jump squat performance between each of the training methods was found. There was a significant difference (p < 0.05) in the first set of each session, with the complex method having a significantly lower peak power. Further, there was a significant difference (p < 0.05) in performance changes between the higher and lower strength groups, with the higher strength group having a greater improvement in performance using the contrast training method compared with the traditional method. It was concluded that contrast training is advantageous for increasing power output but only for athletes with relatively high strength levels.
- Description: 2003000242
Effects of running, static stretching and practice jumps on explosive force production and jumping performance
- Authors: Young, Warren , Behm, David
- Date: 2003
- Type: Text , Journal article
- Relation: Journal of Sports Medicine and Physical Fitness Vol. 43, no. 1 (2003), p. 21-27
- Full Text: false
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- Description: Aim. The interaction between running, stretching and practice jumps during warm-up for jumping tests has not been investigated. The purpose of the present study was to compare the effects of running, static stretching of the leg extensors and practice jumps on explosive force production and jumping performance. Methods. Sixteen volunteers (13 male and 3 female) participated in five different warm-ups in a randomised order prior to the performance of two jumping tests. The warm-ups were control, 4 min run, static stretch, run + stretch, and run + stretch + practice jumps. After a 2 min rest, a concentric jump and a drop jump were performed, which yielded 6 variables expressing fast force production and jumping performance of the leg extensor muscles (concentric jump height, peak force, rate of force developed, drop jump height, contact time and height/time). Results. Generally the stretching warm-up produced the lowest values and the run or run + stretch + jumps warm-ups produced the highest values of explosive force production. There were no significant differences (p<0.05) between the control and run + stretch warm-ups, whereas the run yielded significantly better scores than the run + stretch warm-up for drop jump height (3.2%), concentric jump height (3.4%) and peak concentric force (2.7%) and rate of force developed (15.4%). Conclusion. The results indicated that submaximum running and practice jumps had a positive effect whereas static stretching had a negative influence on explosive force and jumping performance. It was suggested that an alternative for static stretching should be considered in warm-ups prior to power activities.
- Description: C1
- Description: 2003000536
Relationship between a modified Thomas test and leg range of motion in Australian rules football kicking
- Authors: Young, Warren , Clothier, Peter , Otago, Leonie , Bruce, Lyndell , Liddell, David
- Date: 2003
- Type: Text , Journal article
- Relation: Journal of Sport Rehabilitation Vol. 12, no. 4 (2003), p. 343-350
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- Description: Context: Flexibility tests are sometimes thought to be related to range of motion in dynamic activities, but such a relationship remains to be determined. Objective: To determine the correlation between flexibility and hip and knee angles in Australian football kicking. Design: Correlation. Setting: Biomechanics laboratory. Participants: 16 Australian Rules football players. Main Outcome Measures: Hip and knee angles of the preferred kicking leg in a relaxed position were determined with a modified Thomas test. Maximum hip extension, the knee-flexion angle in this position, the maximum knee-flexion angle, and the hip angle at this position during the swing phase of maximum-effort drop-punt kicks were determined. Results: Significant correlations were found between hip flexibility and maximum hip extension (r =.65, P < .01) and hip angle at the maximum knee-flexion angle (r = .70, P < .01). Conclusions: The data indicate a moderate association between hip flexibility and hip angles during kicking.
- Description: C1
- Description: 2003000537
The effect of a resistance training programme on the grab, track and swing starts in swimming
- Authors: Breed, Ray , Young, Warren
- Date: 2003
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 21, no. 3 (2003), p. 213-220
- Full Text: false
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- Description: The aim of this study was to establish the effectiveness of a resistance training programme, designed to improve vertical jumping ability, on the grab, swing and rear-weighted track starts in swimming. Twenty-three female non-competitive swimmers participated (age 19.9±2.4 years; mean±s). The diving techniques were practised weekly for 8 weeks. The participants were randomly assigned to a control group (n = 11) or a resistance-training group (n = 12), which trained three times a week for 9 weeks. The tests before and after the training programme involved performing each dive technique and six dry-land tests: two countermovement jumps (with and without arms), two isokinetic squats (bar speeds of 0.44 and 0.70 rad.s-1) and two overhead throws (with and without back extension). A repeated-measures multivariate analysis of variance was used to show that resistance training improved performance in the dry-land tests (P < 0.0001). No significant improvements due to training were found for any temporal, kinematic or kinetic variables within the grab or swing starts. Significant improvements (P < 0.05) were found for the track start for take-off velocity, take-off angle and horizontal impulse. The results suggest that the improved skill of vertical jumping was not transferred directly to the start, particularly in the grab technique. Non-significant trends towards improvement were observed within all starts for vertical force components, suggesting the need to practise the dives to retrain the changed neuromuscular properties.
- Description: C1
- Description: 2003000554
Acute effects of static stretching on hip flexor and quadriceps flexibility, range of motion and foot speed in kicking a football
- Authors: Young, Warren , Clothier, Peter , Otago, Leonie , Bruce, Lyndell , Liddell, David
- Date: 2004
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 7, no. 1 (Mar 2004), p. 23-31
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- Description: The purpose of this research was to determine the effect of static stretching in a warm-up on hip flexor and quadriceps flexibility as measured by a modified Thomas test and on range of motion (ROM) of the leg and foot speed at impact in kicking a football with maximum effort. Sixteen Australian Rules (AR) footballers performed two different warm-ups on different days. One warm-up involved five minutes of sub-maximum running followed by seven practice kicks, while the other also included 4.5 minutes static stretching of the hip flexors and quadriceps after the running. A modified Thomas test was conduced before and after each warm-up. Players performed maximum effort drop punt kicks into a net while being videotaped to determine the ROM of the kicking leg and foot speed at impact with the ball. There were no significant changes in flexibility (p>0.05) as a result of either warm-up and there were no significant differences between the warm-ups in the kicking variables (p>0.05). It was concluded that the Thomas test may not have been sensitive to possible acute changes in flexibility from the warm-ups, and that stretching had no influence on kicking ROM or foot speed, possibly because of the complexity of the kicking skill.
- Description: C1
- Description: 2003000977
An acute bout of static stretching : Effects on force and jumping performance
- Authors: Power, Kevin , Behm, David , Cahill, Farrell , Carroll, Michael , Young, Warren
- Date: 2004
- Type: Text , Journal article
- Relation: Medicine and Science in Sports and Exercise Vol. 36, no. 8 (2004), p. 1389-1396
- Full Text: false
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- Description: Introduction/Purpose: The objectives of this study were to examine whether a static stretching (SS) routine decreased isometric force, muscle activation, and jump power while improving range of motion (ROM). Second, the study attempted to compare the duration of the dependent variable changes with the duration of the change in ROM. Methods: Twelve participants were tested pre- and post- (POST, 30, 60, 90, and 120 min) SS of the quadriceps and plantar flexors (PF) or a similar period of no stretch (control). Measurements during isometric contractions included maximal voluntary force (MVC), evoked contractile properties (peak twitch and tetanus), surface integrated electromyographic (iEMG) activity of the agonist and antagonistic muscle groups, and muscle inactivation as measured by the interpolated twitch technique (ITT). Vertical jump (VJ) measurements included unilateral concentric-only (no countermovement) jump height as well as drop jump height and contact time. ROM associated with seated hip flexion, prone hip extension, and plantar flexion-dorsiflexion was also recorded. Results: After SS, there were significant overall 9.5% and 5.4% decrements in the torque or force of the quadriceps for MVC and ITT, respectively. Force remained significantly decreased for 120 min (10.4%), paralleling significant percentage increases (6%) in sit and reach ROM (120 min). After SS, there were no significant changes in jump performance or PF measures. Conclusion: The parallel duration of changes in ROM and quadriceps isometric force might suggest an association between stretch-induced changes in muscle compliance and isometric force output.
- Description: C1
- Description: 2003001185
Conflicting effects of fatigue and potentiation on voluntary force
- Authors: Behm, David , Button, Duane , Barbour, Glen , Butt, Jeremy , Young, Warren
- Date: 2004
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 18, no. 2 (2004), p. 365-372
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- Description: The objective of this study was to investigate whether a warm-up consisting of a series of maximal contractions would augment the force and activation of subsequent leg extensor contractions. Both voluntary and evoked isometric contractions were tested to determine the mechanisms underlying the response. Nine subjects were tested for twitch, tetanic, submaximal (30%), and maximal voluntary contractile (MVC) properties before and after (1, 5, 10, and 15 minutes) one to three 10-second MVCs. MVC force either did not change following 1-2 MVCs or was depressed at 10 and 15 minutes after 3 MVCs. MVC activation was decreased (4.4-6.9%) throughout recovery, whereas submaximal contractions were minimally affected. Although overall, twitches were potentiated (15.5-19.8%) posttest, 3 MVCs had significantly greater twitch potentiation than 1 or 2 MVCs at 5 and 10 minutes. Results suggest that voluntary and evoked contractions respond differently to prior 10-second MVCs. In the present study, a warm-up routine of 1-3 MVCs of a 10-second duration did not enhance subsequent voluntary performance.
- Description: C1
- Description: 2003001186
Physiological and anthropometric characteristics of starters and non-starters and playing positions in elite Australian Rules football : A case study
- Authors: Young, Warren , Newton, Robert , Doyle, Tim , Chapman, Dale , Cormack, Stuart , Stewart, Glenn , Dawson, Brian
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 8, no. 3 (Sep 2005), p. 333-345
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- Description: A purpose of this study was to determine if pre-season anthropometric and physiological measures were significantly different for the players from one Australian Football League (AFL) club selected to play in the first game of the season compared to the players not selected. Another purpose was to compare fitness test results for defenders, forwards and mid-fielders in the same AFL club. Thirty-four players were tested for isolated quadriceps and hamstrings strength, leg extensor muscle strength and power, upper body strength, sprinting speed, vertical jump (VJ), endurance, skinfolds and hamstring flexibility. The starters who were selected to play the first game were a significantly older and more experienced playing group, and were significantly better (p < 0.05) in measures of leg power, sprinting speed and the distance covered in the Yo Yo intermittent recovery test compared to the non-starters. Although there were trends for the superiority of the starters, the differences in lower and upper body strength, VJ and predicted VO(2)max were nonsignificant. The forwards generally produced the worst fitness scores of the playing positions with the midfielders having significantly lower skinfolds and the defenders possessing better hamstring strength and VJ compared to the forwards. It was concluded that some fitness qualities can differentiate between starters and non-starters, at least in one AFL club. Comparisons of playing positions and the development of fitness norms for AFL players require further research.
- Description: C1
- Description: 2003001187
The development of a test of reactive agility for netball : A new methodology
- Authors: Farrow, Damian , Young, Warren , Bruce, Lyndell
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 8, no. 1 (2005), p. 52-60
- Full Text: false
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- Description: The purpose of this study was to present a new methodology for the measurement of agility for netball that is considered more ecologically valid than previous agility tests. Specifically, the agility performance of highly-skilled (n=12), moderately-skilled (n=12) and lesser-skilled players (n=8) when responding to a life-size, interactive video display of a netball player initiating a pass was compared to a traditional, pre-planned agility movement where no external stimulus was present. The total movement times and decision times of the players were the primary dependent measures of interest. A second purpose of the research was to determine the test-retest reliability of the testing approach. Results revealed significant differences existed between the 2 test conditions demonstrating that they were measuring different types of agility. The highly-skilled group was significantly faster in both the reactive and planned test conditions relative to the lesser-skilled group, while the moderately-skilled group was significantly faster than the lesser-skilled group in the reactive test condition. The decision time component within the reactive test condition revealed that the highly-skilled players made significantly faster decisions than the lesser-skilled players. It is reasoned that it is this decision-making component of reactive agility that contributes to the significant differences between the two test conditions. The testing approach was shown to have good test-retest reliability with an intra-class correlation of r= .83.
- Description: C1
- Description: 2003001188
Trunk muscle electromyographic activity with unstable and unilateral exercises
- Authors: Behm, David , Leonard, Allison , Young, Warren , Bonsey, Andrew , MacKinnon, Scott N.
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 19, no. 1 (2005), p. 193-201
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- Description: The purpose of this cross-sectional study was to evaluate the effect of unstable and unilateral resistance exercises on trunk muscle activation. Eleven subjects (6 men and 5 women) between 20 and 45 years of age participated. Six trunk exercises, as well as unilateral and bilateral shoulder and chest presses against resistance, were performed on stable (bench) and unstable (Swiss ball) bases. Electromyographic activity of the upper lumbar, lumbosacral erector spinae, and lower-abdominal muscles were monitored. Instability generated greater activation of the lower-abdominal stabilizer musculature (27.9%) with the trunk exercises and all trunk stabilizers (37.7-54.3%) with the chest press. There was no effect of instability on the shoulder press. Unilateral shoulder press produced greater activation of the back stabilizers, and unilateral chest press resulted in higher activation of all trunk stabilizers, when compared with bilateral presses. Regardless of stability, the superman exercise was the most effective trunk-stabilizer exercise for back-stabilizer activation, whereas the side bridge was the optimal exercise for lower-abdominal muscle activation. Thus, the most effective means for trunk strengthening should involve back or abdominal exercises with unstable bases. Furthermore, trunk strengthening can also occur when performing resistance exercises for the limbs, if the exercises are performed unilaterally. © 2005 National Strength & Conditioning Association.
- Description: C1
- Description: 2003001184
A review of agility : Practical applications for strength and conditioning
- Authors: Young, Warren , Farrow, Damian
- Date: 2006
- Type: Text , Journal article
- Relation: Strength and Conditioning Journal Vol. 28, no. 5 (2006), p. 24-29
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- Description: Agility is an important component of many sports but has not been extensively researched. The various components that contribute to agility performance are discussed and training guidelines are provided. There appears to be limited transfer to agility performance from straight sprint training as well as from general strength training. The principle of training specificity is emphasized to achieve maximum transfer to on-field performance.
- Description: C1
- Description: 2003002120
Agility literature review : Classifications, training and testing
- Authors: Sheppard, Jeremy , Young, Warren
- Date: 2006
- Type: Text , Journal article
- Relation: Journal of Sports Sciences Vol. 24, no. 9 (Sep 2006), p. 919-932
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- Description: At present, no agreement on a precise definition of agility within the sports science community exists. The term is applied to a broad range of sport contexts, but with such great inconsistency, it further complicates our understanding of what trainable components may enhance agility. A new definition of agility is proposed: "a rapid whole-body movement with change of velocity or direction in response to a stimulus". Agility has relationships with trainable physical qualities such as strength, power and technique, as well as cognitive components such as visual-scanning techniques, visual-scanning speed and anticipation. Agility testing is generally confined to tests of physical components such as change of direction speed, or cognitive components such as anticipation and pattern recognition. New tests of agility that combine physical and cognitive measures are encouraged.
- Description: C1
- Description: 2003002129
An evaluation of a new test of reactive agility and its relationship to sprint speed and change of direction speed
- Authors: Sheppard, Jeremy , Young, Warren , Doyle, Tim , Sheppard, T. A. , Newton, Robert
- Date: 2006
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 9, no. 4 (2006), p. 342-349
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- Description: The purpose of this study was to evaluate the reliability and validity of a new test of agility, the reactive agility test (RAT), which included anticipation and decision-making components in response to the movements of a tester. Thirty-eight Australian football players took part in the study, categorized into either a higher performance group (HPG) (n = 24) or lower performance group (LPG) (n = 14) based on playing level from the previous season. All participants undertook testing of a 10 m straight sprint (10 mSS), a 8-9 m change of direction speed test (CODST), and the RAT. Test-retest and inter-tester reliability testing measures were conducted with the LPG. The intra-class correlation (ICC) of the RAT was 0.870, with no significant (p < 0.05) difference between the test results obtained on the first and second test sessions using a t-test. A dependent samples t-test revealed no significant (p < 0.05) difference between the test results of two different testers with the same population. The HPG were significantly (p = 0.001) superior to those of the LPG on the RAT, with no differences observed on any other variable. The RAT is an acceptably reliable test when considering both test-retest reliability, as well as inter-rater reliability. In addition, the test was valid in distinguishing between players of differing performance level in Australian football, while the 10 mSS and CODST were not. This result suggests that traditional closed skill sprint and sprint with direction change tests may not adequately distinguish between players of different levels of competition in Australian football. © 2006 Sports Medicine Australia.
- Description: C1
- Description: 2003002132
Effects of static stretching volume and intensity on plantar flexor explosive force production and range of motion
- Authors: Young, Warren , Elias, G. , Power, J.
- Date: 2006
- Type: Text , Journal article
- Relation: Journal of Sports Medicine and Physical Fitness Vol. 46, no. 3 (2006), p. 403-411
- Full Text: false
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- Description: Aim. The aim of the study was to determine the effects of volume and intensity of static stretching in a warm-up on explosive force production and range of motion (ROM) of the plantar flexors. Methods. Twenty subjects performed 5 warm-ups on different days. The warm-ups contained a 5 min treadmill run and various protocols of 30 s static stretches (SS) of the plantar flexors. Stretching involved dorsi flexion just before the pain threshold, which was considered 100% intensity. The treatments that immediately followed the run were: (i) no other treatment (control); (ii) 1 min SS; (iii) 2 min SS; (iv) 4 min SS; (v) 2 min SS at 90% intensity. Ankle ROM was assessed before and after each warm-up and a concentric calf raise and drop jump (DJ) test was conducted after each warm-up. Results. There were no significant differences (P>0.05) in peak force or rate of force production in the explosive calf raise between any of the warm-ups. However the run plus 2 min stretch and the run plus 4 min stretch protocols produced significantly lower (P<0.05) DJ performance (jump height/ground contact time) than the run. The run plus 4 min stretch warm-up also produced a significantly lower DJ score than the run plus 1 min stretch warm-up. There were no significant differences between any of the warm-ups in ankle ROM. Conclusions. The addition of 2-4 min of SS at 100% intensity to a run caused an impairment to fast stretch shortening cycle muscle performance. The greater impairment from the 4 min stretching condition supported a volume-effect. Two minutes of stretching at 90% intensity had no significant influence on muscle function. The addition of up to 4 min of SS to a run had no appreciable effect on ankle ROM, possibly because of the prior influence of the run.
- Description: C1
- Description: 2003002135