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
- Reviewed:
- 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
Examining age and gender effects in physical performance in young athletes aged 12-16 years
- Authors: Yanci, Javier , Cámara, Jesus , Vizcay, Juan , Young, Warren
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal of Sports Science and Coaching Vol. 11, no. 4 (2016), p. 538-544
- Full Text: false
- Reviewed:
- Description: The aims of the present study were to determine anthropometric and physical characteristics according to age and gender of young athletes, and to quantify the relationships among these characteristics. Sixty-four young high-level runners were divided into two groups according to their age: U14 = under 14 year's athletes; U16 = under 16 year's athletes. The U16 group presented higher values of the sprint 15 m (p < 0.01, d = 1.14) and modified agility test (p < 0.01, d = 0.66) than the U14 group. However, the boys group presented higher values in the 505 agility test (p < 0.01, d = 0.63), modified agility test (p < 0.01, d = 1.26), horizontal countermovement jump (p < 0.05, d = 0.56), vertical countermovement jump (p < 0.01, d = 0.61) and arm swim vertical countermovement jump (p < 0.01, d = 0.63) than the girls group. © The Author(s) 2016.
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
- Reviewed:
- 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
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
- Reviewed:
- 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
The effects of sprint training and the Nordic hamstring exercise on eccentric hamstring strength and sprint performance in adolescent athletes
- Authors: Freeman, Brock , Young, Warren , Talpey, Scott , Smyth, Andrew , Pane, Calvin , Carlon, Todd
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Sports Medicine and Physical Fitness Vol. 59, no. 7 (2019), p. 1119-1125
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- Description: BACKGROUND. Hamstring strain injuries (HSI) are among the most common injuries in field-based team sports with a high-speed running component. The implementation of the Nordic hamstring exercise (NHE) is a well-documented method of improving eccentric hamstring strength to mitigate the risk of HSI occurrence. Sprint training is specific to the injury mechanism and is thought to activate the hamstrings through maximal eccentric contractions. The purpose of this study was to compare the effects of sprint training and the NHE on eccentric hamstring strength and sprint performance. METHODS. Twenty-eight participants (mean +/- SD age=16.21 +/- 1.34 years; height=1.75m +/- 0.10m; body mass=68.5kg +/- 12.1kg) completed an eccentric hamstring strength assessment and 40m sprint to assess acceleration and maximum speed. Participants were randomly allocated to either a NHE training or sprint training group. Two sessions per week for four-weeks of training was performed with baseline testing procedures repeated in the week following the intervention. Perceptions of soreness were recorded following the warm-up in each training session. RESULTS. Both the NHE (effect size=0.39, P<0.05) and sprint training (effect size=0.29, P<0.05) groups displayed significant gains in eccentric hamstring strength. The NHE group reported trivial improvements in sprint performance, whilst the sprint training group experienced a moderate improvement, specifically in maximum speed (ES=0.83 Moderate). Sprint training also produced greater perceptions of soreness than the NHE following a four-week training intervention, specifically before the start of the last session (P<0.05). CONCLUSIONS. These findings indicate that sprint training had a beneficial effect for both eccentric hamstring strength and sprint performance, whilst also producing greater soreness than the NHE following the final training session. It was concluded that a four-week block of maximum speed training may have both an injury prevention and performance enhancement benefit.