Isokinetic force profile of the cervical spine in a healthy adult urban South African population
- Authors: Olivier, Pierre Emile
- Date: 2008
- Subjects: Cervical vertebrae , Neck -- Muscles , Muscle strength -- Testing
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10102 , http://hdl.handle.net/10948/982 , Cervical vertebrae , Neck -- Muscles , Muscle strength -- Testing
- Description: The aim of this study was to establish reference data for the cervical spine’s dynamic force characteristics in a healthy adult urban South African population aged 19 to 69 years. The reference data was classified according to gender discriminate age categories. In total ten gender discriminate age categories, five male and five female, were created; 19 to 29, 30 to 39, 40 to 49, 50 to 59 and 60 to 69-year-olds. The force characteristics measured, analysed and used to generate reference data in stanine format were: absolute peak torque (P-), relative peak torque (P-/BW), peak power (Pow-), relative peak power (Pow-/BW), peak work (W-), relative peak work (W-/BW), torque acceleration energy (TAE-), maximal voluntary cervical muscle contraction range of motion (MVCR-), controlled full range of joint motion (CFR-), joint angle at peak torque (Jang@P-) and peak torque ratios for cervical flexion (-F), extension (-E), lateral flexion to the dominant (-LD) and non-dominant (-LN) sides. In addition biographic and anthropometric data was also collected. Data, grouped in the ten gender discriminate age categories were compared and statistically and practically significant differences were highlighted between the gender discriminate age categories. Inferential statistics used included ANOVA and Cohen’s d. A significance level of α = .05 was used in all inferential statistical analyses. Correlations between various anthropometric and isokinetic strength variables were also explored.
- Full Text:
- Date Issued: 2008
- Authors: Olivier, Pierre Emile
- Date: 2008
- Subjects: Cervical vertebrae , Neck -- Muscles , Muscle strength -- Testing
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10102 , http://hdl.handle.net/10948/982 , Cervical vertebrae , Neck -- Muscles , Muscle strength -- Testing
- Description: The aim of this study was to establish reference data for the cervical spine’s dynamic force characteristics in a healthy adult urban South African population aged 19 to 69 years. The reference data was classified according to gender discriminate age categories. In total ten gender discriminate age categories, five male and five female, were created; 19 to 29, 30 to 39, 40 to 49, 50 to 59 and 60 to 69-year-olds. The force characteristics measured, analysed and used to generate reference data in stanine format were: absolute peak torque (P-), relative peak torque (P-/BW), peak power (Pow-), relative peak power (Pow-/BW), peak work (W-), relative peak work (W-/BW), torque acceleration energy (TAE-), maximal voluntary cervical muscle contraction range of motion (MVCR-), controlled full range of joint motion (CFR-), joint angle at peak torque (Jang@P-) and peak torque ratios for cervical flexion (-F), extension (-E), lateral flexion to the dominant (-LD) and non-dominant (-LN) sides. In addition biographic and anthropometric data was also collected. Data, grouped in the ten gender discriminate age categories were compared and statistically and practically significant differences were highlighted between the gender discriminate age categories. Inferential statistics used included ANOVA and Cohen’s d. A significance level of α = .05 was used in all inferential statistical analyses. Correlations between various anthropometric and isokinetic strength variables were also explored.
- Full Text:
- Date Issued: 2008
The influence of an adapted knee angle, as determined by isokinetic assessment, on sprint starting performance
- Authors: Schultz, Adrian Brent
- Date: 2004
- Subjects: Sprinting -- South Africa -- Physiological aspects -- Testing , Muscle strength -- Testing , Runners (Sports) -- South Africa -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11029 , http://hdl.handle.net/10948/317 , Sprinting -- South Africa -- Physiological aspects -- Testing , Muscle strength -- Testing , Runners (Sports) -- South Africa -- Testing
- Description: Muscle strength has been identified as an important contributor to athletic performance. Little attention however, has been paid to the specific relationship between peak isokinetic muscle strength and sprint starting performance. The aim of this study was to determine the influence of an adapted front knee angle, as determined by isokinetic assessment (the angle of peak torque production), on starting performance. Sixteen track sprinters, of elite-national or competitive-regional standard, were asked to perform eight sprints over 50m using four separate starting techniques. Technique 1 featured the athlete’s usual starting preferences while Techniques 2, 3 and 4 featured a standardised set of starting preferences with experimental modifications of the front knee angle in the “set” position. Isokinetic muscle strength was measured at slow (60°/s) and fast (240°/s) test speeds in order to determine the angle of peak torque production for concentric knee extension of each subject’s lead leg. Using one-way analysis of variance (ANOVA) and Post Hoc analysis (LSD), no significant differences (p>0.05) were observed between the experimental techniques for: block time, force-time measures during block time, sprint times, sprint velocity and acceleratio n measures at intervals up to 50m. Significant differences (p<0.05) were however observed between reaction times for the experimental techniques. Slower reaction times are most likely due to increased upper body pretension, resulting from the increased hip elevation seen for these techniques. The results indicate that increased hip elevation may have delayed the initiation of the relevant motor response required to affect an optimal sprint start. Technique 1 resulted in the shortest reaction times, shortest block times, fastest sprint times and greatest sprint velocities for all four techniques. This result was possibly due to the athlete’s experience with, and repeated use of, this technique. The experimental techniques therefore provided no added advantage over the subject’s preferred starting technique and did not significantly optimise sprint starting performance. The results show that modification of the front knee angle had no significant influence on sprint starting performance and sprint running ve locity or acceleration patterns up to 50m. Using Pearson’s Correlation Coefficient to determine the strongest correlations between isokinetic knee strength and sprint starting performance, analysis revealed that the strongest relationships were found between sprint starting performance expressed as acceleration and isokinetic knee strength expressed as relative peak torque and absolute peak torque. For Technique 1 the strongest correlation was found between acceleration (30m - 40m) and relative peak torque as measured at a test speed of 240°/s (r = 0.62). For the remaining experimental techniques, the strongest correlation was found between acceleration (10m - 20m) and relative peak torque as measured at a test speed of 60°/s (r = 0.53) for Technique 2, between acceleration (40m - 50m) and peak torque measured at a test speed of 60°/s (r = 0.72) for Technique 3, and between acceleration (0m - 5m) and peak torque as measured at a test speed of 240°/s (r = 0.71) for Technique 4. These results suggest that isokinetic muscle strength does not correlate strongly with sprint starting performance and that additional factors, such as neuromuscular organisation and muscle fibre typing, possibly make a greater contribution to optimal sprint starting performance.
- Full Text:
- Date Issued: 2004
- Authors: Schultz, Adrian Brent
- Date: 2004
- Subjects: Sprinting -- South Africa -- Physiological aspects -- Testing , Muscle strength -- Testing , Runners (Sports) -- South Africa -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11029 , http://hdl.handle.net/10948/317 , Sprinting -- South Africa -- Physiological aspects -- Testing , Muscle strength -- Testing , Runners (Sports) -- South Africa -- Testing
- Description: Muscle strength has been identified as an important contributor to athletic performance. Little attention however, has been paid to the specific relationship between peak isokinetic muscle strength and sprint starting performance. The aim of this study was to determine the influence of an adapted front knee angle, as determined by isokinetic assessment (the angle of peak torque production), on starting performance. Sixteen track sprinters, of elite-national or competitive-regional standard, were asked to perform eight sprints over 50m using four separate starting techniques. Technique 1 featured the athlete’s usual starting preferences while Techniques 2, 3 and 4 featured a standardised set of starting preferences with experimental modifications of the front knee angle in the “set” position. Isokinetic muscle strength was measured at slow (60°/s) and fast (240°/s) test speeds in order to determine the angle of peak torque production for concentric knee extension of each subject’s lead leg. Using one-way analysis of variance (ANOVA) and Post Hoc analysis (LSD), no significant differences (p>0.05) were observed between the experimental techniques for: block time, force-time measures during block time, sprint times, sprint velocity and acceleratio n measures at intervals up to 50m. Significant differences (p<0.05) were however observed between reaction times for the experimental techniques. Slower reaction times are most likely due to increased upper body pretension, resulting from the increased hip elevation seen for these techniques. The results indicate that increased hip elevation may have delayed the initiation of the relevant motor response required to affect an optimal sprint start. Technique 1 resulted in the shortest reaction times, shortest block times, fastest sprint times and greatest sprint velocities for all four techniques. This result was possibly due to the athlete’s experience with, and repeated use of, this technique. The experimental techniques therefore provided no added advantage over the subject’s preferred starting technique and did not significantly optimise sprint starting performance. The results show that modification of the front knee angle had no significant influence on sprint starting performance and sprint running ve locity or acceleration patterns up to 50m. Using Pearson’s Correlation Coefficient to determine the strongest correlations between isokinetic knee strength and sprint starting performance, analysis revealed that the strongest relationships were found between sprint starting performance expressed as acceleration and isokinetic knee strength expressed as relative peak torque and absolute peak torque. For Technique 1 the strongest correlation was found between acceleration (30m - 40m) and relative peak torque as measured at a test speed of 240°/s (r = 0.62). For the remaining experimental techniques, the strongest correlation was found between acceleration (10m - 20m) and relative peak torque as measured at a test speed of 60°/s (r = 0.53) for Technique 2, between acceleration (40m - 50m) and peak torque measured at a test speed of 60°/s (r = 0.72) for Technique 3, and between acceleration (0m - 5m) and peak torque as measured at a test speed of 240°/s (r = 0.71) for Technique 4. These results suggest that isokinetic muscle strength does not correlate strongly with sprint starting performance and that additional factors, such as neuromuscular organisation and muscle fibre typing, possibly make a greater contribution to optimal sprint starting performance.
- Full Text:
- Date Issued: 2004
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