A deterministic model of the vertical jump : Implications for training
- Ham, Daniel, Knez, Wade, Young, Warren
- Authors: Ham, Daniel , Knez, Wade , Young, Warren
- Date: 2007
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 21, no. 3 (2007), p. 967-972
- Full Text:
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- Description: A deterministic model of the vertical jump: implications for training. J. Strength Cond. Res. 21(3):967-972. 2007. - Increasing vertical jump height is a critical component for performance enhancement in many sports. It takes on a number of different forms and conditions, including double and single legged jumps and stationary and run-up jumps. In an attempt to understand the factors that influence vertical jump performance, an extensive analysis was undertaken using the deterministic model. Once identified, practical training strategies enabling improvement in these factors were elucidated. Our analysis showed that a successful vertical jump performance was the result of a complex interplay of run-up speed, reactive strength, concentric action power of the take-off leg(s), hip flexors, shoulders, body position, body mass, and take-off time. Of special interest, our analysis showed that the concentric action power of the legs was the critical factor affecting stationary double leg vertical jumps, whereas reactive strength was the critical component for a single leg jump from a run-up. © 2007 National Strength & Conditioning Association.
- Description: C1
- Description: 2003005651
- Authors: Ham, Daniel , Knez, Wade , Young, Warren
- Date: 2007
- Type: Text , Journal article
- Relation: Journal of Strength and Conditioning Research Vol. 21, no. 3 (2007), p. 967-972
- Full Text:
- Reviewed:
- Description: A deterministic model of the vertical jump: implications for training. J. Strength Cond. Res. 21(3):967-972. 2007. - Increasing vertical jump height is a critical component for performance enhancement in many sports. It takes on a number of different forms and conditions, including double and single legged jumps and stationary and run-up jumps. In an attempt to understand the factors that influence vertical jump performance, an extensive analysis was undertaken using the deterministic model. Once identified, practical training strategies enabling improvement in these factors were elucidated. Our analysis showed that a successful vertical jump performance was the result of a complex interplay of run-up speed, reactive strength, concentric action power of the take-off leg(s), hip flexors, shoulders, body position, body mass, and take-off time. Of special interest, our analysis showed that the concentric action power of the legs was the critical factor affecting stationary double leg vertical jumps, whereas reactive strength was the critical component for a single leg jump from a run-up. © 2007 National Strength & Conditioning Association.
- Description: C1
- Description: 2003005651
An integrated physiological and performance profile of professional tennis
- Hornery, Daniel, Farrow, Damian, Mujika, Inigo, Young, Warren
- Authors: Hornery, Daniel , Farrow, Damian , Mujika, Inigo , Young, Warren
- Date: 2007
- Type: Text , Journal article
- Relation: British Journal of Sports Medicine Vol. 41, no. 8 (2007), p. 531-536
- Full Text: false
- Reviewed:
- Description: Objective: To describe the physiological responses to tournament tennis in relation to prevailing environmental conditions, match notation, and skills that underpin performance. Design: 14 male professional tennis players (mean (SD) age, 21.4 (2.6) years; height, 183.0 (6.9) cm; body mass, 79.2 (6.4) kg) were studied while contesting international tennis tournaments. Environmental conditions, match notation, physiological (core temperature, hydration status, heart rate, blood variables), and performance indices (serve kinematics, serve velocity, error rates) were recorded. Results: Hard and clay court tournaments elicited similar peak core temperature (38.9 (0.3) v 38.5 (0.6)°C) and average heart rate (152 (15) v 146 (19) beats/min) but different body mass deficit (1.05 (0.49) v 0.32 (0.56)%, p<0.05). Average pre-match urine specific gravity was 1.022 (0.004). Time between points was longer during hard court matches (25.1 (4.3) v 17.2 (3.3) s, p<0.05). Qualitative analysis of first and second serves revealed inverse relations between the position of the tossing arm at ball release and the position of the ball toss and progressive match time (respectively, r= -0.74 and r= -0.73, p<0.05) and incurred body mass deficit (r=0.73 and r=0.73, p<0.05). Conclusions: Participants began matches in a poor state of hydration, and experienced moderate thermoregulatory strain and dehydration during competition. These adverse physiological conditions may compromise performance and influence notational analyses.
- Description: C1
- Description: 2003005645
Trunk muscle electromyographic activity with unstable and unilateral exercises
- Behm, David, Leonard, Allison, Young, Warren, Bonsey, Andrew, MacKinnon, Scott N.
- 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
- 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
- Full Text:
- Reviewed:
- 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
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