Caffeine, carbohydrate, and cooling use during prolonged simulated tennis
- Hornery, Daniel, Mujika, Inigo, Young, Warren, Farrow, Damian
- Authors: Hornery, Daniel , Mujika, Inigo , Young, Warren , Farrow, Damian
- Date: 2007
- Type: Text , Journal article
- Relation: International Journal of Sports Physiology and Performance Vol. 2, no. 4 (2007), p. 423-438
- Full Text:
- Reviewed:
- Description: Purpose: To determine the effects of prolonged simulated tennis on performance and the ergogenic potential of caffeine, carbohydrates, and cooling. Methods: Twelve highly trained male tennis players (age 18.3 ± 3.0 y, height 178.8 ± 8.5 cm, body mass 73.95 ± 12.30 kg, mean ± SD) performed 4 simulated matches (2 h 40 min) against a ball machine on an indoor hard court. The counterbalanced experimental trials involved caffeine supplementation (3 mg/kg), carbohydrate supplementation (6% solution), precooling and intermittent cooling, and placebo control. Physiological markers (core temperature, heart rate, blood lactate, and blood glucose), subjective responses (ratings of perceived exertion and thermal sensation), stroke velocity and accuracy, serve kinematics, and tennis-specific perceptual skill quantified the efficacy of interventions. Results: Significant effects of time (P < .01) reflected increased physiological demand, reduced serve velocity and ground-stroke velocity and accuracy, and a slowing of the serve racket-arm acceleration phase. Caffeine increased serve velocity (165 ± 15 km/h) in the final set of the match (P = .014) compared with placebo (159 ± 15 km/h, P = .008) and carbohydrate (158 ± 13 km/h, P = .001) conditions. Carbohydrate and cooling conditions afforded physiological advantage (increased blood glucose, P < .01, and reduced preexercise thermal sensation, P < .01) but did not affect performance relative to the placebo condition. Conclusions: Prolonged simulated tennis induced significant decrements in tennis skills. Caffeine supplementation partly attenuated the effects of fatigue and increased serve velocity. In contrast, carbohydrate and cooling strategies had little ergogenic effect on tennis performance.
- Description: C1
- Description: 2003005648
- Authors: Hornery, Daniel , Mujika, Inigo , Young, Warren , Farrow, Damian
- Date: 2007
- Type: Text , Journal article
- Relation: International Journal of Sports Physiology and Performance Vol. 2, no. 4 (2007), p. 423-438
- Full Text:
- Reviewed:
- Description: Purpose: To determine the effects of prolonged simulated tennis on performance and the ergogenic potential of caffeine, carbohydrates, and cooling. Methods: Twelve highly trained male tennis players (age 18.3 ± 3.0 y, height 178.8 ± 8.5 cm, body mass 73.95 ± 12.30 kg, mean ± SD) performed 4 simulated matches (2 h 40 min) against a ball machine on an indoor hard court. The counterbalanced experimental trials involved caffeine supplementation (3 mg/kg), carbohydrate supplementation (6% solution), precooling and intermittent cooling, and placebo control. Physiological markers (core temperature, heart rate, blood lactate, and blood glucose), subjective responses (ratings of perceived exertion and thermal sensation), stroke velocity and accuracy, serve kinematics, and tennis-specific perceptual skill quantified the efficacy of interventions. Results: Significant effects of time (P < .01) reflected increased physiological demand, reduced serve velocity and ground-stroke velocity and accuracy, and a slowing of the serve racket-arm acceleration phase. Caffeine increased serve velocity (165 ± 15 km/h) in the final set of the match (P = .014) compared with placebo (159 ± 15 km/h, P = .008) and carbohydrate (158 ± 13 km/h, P = .001) conditions. Carbohydrate and cooling conditions afforded physiological advantage (increased blood glucose, P < .01, and reduced preexercise thermal sensation, P < .01) but did not affect performance relative to the placebo condition. Conclusions: Prolonged simulated tennis induced significant decrements in tennis skills. Caffeine supplementation partly attenuated the effects of fatigue and increased serve velocity. In contrast, carbohydrate and cooling strategies had little ergogenic effect on tennis performance.
- Description: C1
- Description: 2003005648
Strength classification and diagnosis : not all strength is created equal
- James, Lachlan, Talpey, Scott, Young, Warren, Geneau, Mary, Newton, Robert, Gastin, Paul
- Authors: James, Lachlan , Talpey, Scott , Young, Warren , Geneau, Mary , Newton, Robert , Gastin, Paul
- Date: 2023
- Type: Text , Journal article
- Relation: Strength and Conditioning Journal Vol. 45, no. 3 (2023), p. 333-341
- Full Text: false
- Reviewed:
- Description: Maximal force can be expressed across a range of conditions influenced by the external load and the time available to express force. As a result, several distinct and specific strength qualities exist. Conversely, some expressions of maximal force are similar and can be categorized as a single quality. Therefore, strength assessment systems must be sophisticated enough to isolate and measure each quality while minimizing redundant information. This article presents a contemporary, evidence-based and practical framework that reduces the many strength and speed-strength metrics into 5 distinct qualities. Alongside this, we present case examples of the application of strength diagnosis. © 2023 Lippincott Williams and Wilkins. All rights reserved.
Relationship between pre-season anthropometric and fitness measures and indicators of playing performance in elite junior Australian rules football
- Authors: Young, Warren , Pryor, Luke
- Date: 2007
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 10, no. 2 (2007), p. 110-118
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- Description: The purpose of this research was to determine the relationships between selected anthropometric and fitness measures with indicators of performance in elite junior Australian football players. During the pre-season, 485 players from the elite Victorian under-18 Australian Rules football competition were tested for height, body mass, hand span, arm length, standing reach, vertical jump, 5 and 20 m sprint times, agility, predicted over(V, ) O2 max and sit and reach flexibility. Performance indicators included being selected for the first game of the season and the number of possessions, marks, hitouts, and the number of games where votes were awarded in the first eight games of the season. The top and bottom four teams on the ladder were also compared after eight games. Players were divided into groups on the basis of the above indicators and the groups were compared statistically by analysis of variance (ANOVA). There were several significant differences between selected and non-selected players. Players acquiring the most possessions were significantly (p < 0.05) shorter (effect size: ES = 0.78), with less body mass (ES = 0.55) and possessed greater acceleration (ES = 0.44-0.56) and endurance (ES = 0.51). Body mass was significantly related to the number of marks and height was related to hitouts (p < 0.05). Acceleration was the only fitness quality to discriminate between higher and lower vote winners. The players from the top four teams had a significantly greater standing reach (p = 0.038, ES = 0.53), were heavier (p = 0.032, ES = 0.55) but not superior in any fitness measure. Generally hand span, agility and flexibility were not related to performance indicators. It was concluded that shorter and lighter players who possess high levels of speed and endurance are more likely to acquire possessions and be awarded votes, however these attributes do not guarantee team success. The small relationships between agility and flexibility to performance might be explained by the choice of tests used to assess these qualities. © 2006 Sports Medicine Australia.
- Description: C1
- Description: 2003005642
- Authors: Young, Warren , Pryor, Luke
- Date: 2007
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 10, no. 2 (2007), p. 110-118
- Full Text:
- Reviewed:
- Description: The purpose of this research was to determine the relationships between selected anthropometric and fitness measures with indicators of performance in elite junior Australian football players. During the pre-season, 485 players from the elite Victorian under-18 Australian Rules football competition were tested for height, body mass, hand span, arm length, standing reach, vertical jump, 5 and 20 m sprint times, agility, predicted over(V, ) O2 max and sit and reach flexibility. Performance indicators included being selected for the first game of the season and the number of possessions, marks, hitouts, and the number of games where votes were awarded in the first eight games of the season. The top and bottom four teams on the ladder were also compared after eight games. Players were divided into groups on the basis of the above indicators and the groups were compared statistically by analysis of variance (ANOVA). There were several significant differences between selected and non-selected players. Players acquiring the most possessions were significantly (p < 0.05) shorter (effect size: ES = 0.78), with less body mass (ES = 0.55) and possessed greater acceleration (ES = 0.44-0.56) and endurance (ES = 0.51). Body mass was significantly related to the number of marks and height was related to hitouts (p < 0.05). Acceleration was the only fitness quality to discriminate between higher and lower vote winners. The players from the top four teams had a significantly greater standing reach (p = 0.038, ES = 0.53), were heavier (p = 0.032, ES = 0.55) but not superior in any fitness measure. Generally hand span, agility and flexibility were not related to performance indicators. It was concluded that shorter and lighter players who possess high levels of speed and endurance are more likely to acquire possessions and be awarded votes, however these attributes do not guarantee team success. The small relationships between agility and flexibility to performance might be explained by the choice of tests used to assess these qualities. © 2006 Sports Medicine Australia.
- Description: C1
- Description: 2003005642
The use of static stretching in warm-up for training and competition
- Authors: Young, Warren
- Date: 2007
- Type: Text , Journal article
- Relation: International journal of sports physiology and performance Vol. 2, no. 2 (2007), p. 212-216
- Full Text: false
- Description: Static stretching (SS) is widely used in warm-ups before training and competition. A growing amount of research, however, has demonstrated that SS can impair muscle performance, leading to a reevaluation of optimal warm-up protocols. This commentary discusses many of the methodological issues that can influence conclusions about the acute effects of SS on performance. One difficulty in interpreting the literature is the lack of control or communication about the volume and intensity of the various stretching treatments used. Another major issue is the failure of many researchers to evaluate SS as it is used in practice, particularly the interaction with the other general and sport-specific components of the warm-up. Acute warm-up effects on performance should be considered in conjunction with potential effects on injury prevention. Future directions in research include optimizing general and sport-specific warm-ups, time course of physiological and performance effects, and individualization of warm-ups according to fitness and skill level.
- Description: 2003005660
Physiological and anthropometric characteristics of starters and non-starters and playing positions in elite Australian Rules football : A case study
- Young, Warren, Newton, Robert, Doyle, Tim, Chapman, Dale, Cormack, Stuart, Stewart, Glenn, Dawson, Brian
- 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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- Reviewed:
- 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
- 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
- Full Text:
- Reviewed:
- 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
Acute effects of static stretching on hip flexor and quadriceps flexibility, range of motion and foot speed in kicking a football
- Young, Warren, Clothier, Peter, Otago, Leonie, Bruce, Lyndell, Liddell, David
- 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
- Full Text:
- Reviewed:
- 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
- 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
- Full Text:
- Reviewed:
- 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
Which jump variables should be used to assess explosive leg muscle function?
- Young, Warren, Cormack, Stuart, Crichton, Michael
- Authors: Young, Warren , Cormack, Stuart , Crichton, Michael
- Date: 2011
- Type: Text , Journal article
- Relation: International Journal of Sports Physiology and Performance Vol. 6, no. 1 (2011), p. 51-57
- Full Text:
- Reviewed:
- Description: Purpose: The main purpose of this study was to determine the relationships between countermovement jump (CMJ) variables and acceleration and maximum speed performance. Methods: Twenty-three elite Australian football players were tested on a CMJ, which yielded several kinematic and kinetic variables describing leg muscle function. A 40 m sprint was also conducted to assess acceleration (10 m time) and an estimate of maximum speed (flying 20 m time). Players from one Australian Football League (AFL) club were tested and Pearson correlations for CMJ variables and sprint performance were calculated. Results: Jump height, peak velocity, peak force, and peak power had less than 50% common variance, and therefore represented independent expressions of CMJ performance. Generally, the correlations between CMJ variables and sprinting performance were stronger for maximum speed (small to large effect sizes) than for acceleration (trivial to moderate sizes). The variable that produced the strongest correlation with acceleration was jump height (r = -0.430, P = .041) and with maximum speed was peak power/weight (r = -0.649, P = .001). Conclusions: The results indicate that if an integrated system comprising a position transducer and a force platform is available for CMJ assessment, jump height and peak power/weight are useful variables to describe leg muscle explosive function for athletes who perform sprints.
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