Thesis
The relationship between different protocols of resistance exercise and the development of muscle power: implications for muscular and neural adaptation
Southern Cross University, School of Exercise Science and Sports Management
Doctor of Philosophy (PhD), Southern Cross University
1998
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Abstract
The purpose of this thesis was to investigate the relationship between various protocols of resistance exercise and the development of muscle power and examine accompanying changes in muscular and neural physiology. This thesis consists of a cross-sectional and longitudinal investigation encompassing four separate experiments.
Experiment One
A Comparison of Strength and Power Characteristics Between Powerlifters, Weightlifters and Sprinters
The purpose of this investigation was to determine the effect of involvement in powerlifting, weightlifting and sprinting on strength and power characteristics in the squat movement. A standard one repetition maximum squat test (lRM), jump squat tests and vertical jumps with various loads were performed. Peak force (PF), peak velocity (PV), peak power (PP) and jump height (JH) were determined for the jump squats and vertical jumps from force plate and position transducer measurements. The powerlifters (PL, n = 8), weightlifters (WL, n = 6), and sprinters (S, n = 6) were significantly stronger than the controls in the lRM (C, n = 8) (p<_ 0.05). In addition, the WL group was significantly stronger than the S group. The WL group was significantly higher in PF, PP, PV, and JH and the S group was significantly higher in PV and JH in comparison to the PL and C groups for jump trials at various loads. The PL group was significantly higher in PF and PP for jump trials at various loads in comparison to the C group. A differential expression of muscle power was observed with the S group producing high velocities and the PL group producing high forces both resulting in relatively similar power levels. The WL group was capable of producing high velocities and forces simultaneously and thus produced the highest observed power levels. The data indicates that strength and power characteristics are specific to each group and are most likely influenced by the various training protocols utilised.
Experiment Two
The Relationship Between Titin and Muscle Power and Strength in Various Athletic Populations
The purpose of this investigation was to determine if any relationship existed between various characteristics of the muscle protein titin and vertical jumping and squatting ability in different athletic populations. Subjects fell into one of four groups: 1) non-athletes (NA) (n = 5), 2) weightlifters (WL) (n = 5), 3) powerlifters (PL) (n = 5), 4) sprinters (S) (n = 5). A one repetition maximum in the squat exercise (lRM), countermovement (CMJ) jump and static (SJ) vertical jump trials were performed. Peak force (PF), peak power (PP), peak velocity (PV) and jump height (JH) were calculated for the vertical jumps from force plate measurements. Gel electrophoresis was used for analysis of muscle samples. Titin-1 (Tl) and titin-2 (T2) protein bands were identified, quantified and expressed relative to each other. In addition, the relative mobility (Rf) of Tl and T2 was determined as an estimate of molecular weight. The NA group (%Tl= 47.8±5.1, %T2 = 52.2±5.1) had lower Tl and higher T2 percentages in comparison to the WL (%Tl= 62.3±6.6, %T2 = 37.7±6.6), PL (%Tl= 66.8±5.0, %T2 = 33.2±5.0) and S (%Tl= 65.9±4.9, %T2 = 34.1±4.9) groups (p:5:0.10). A significant correlation was found between force capabilities in vertical jumping (PFCMJ, PFSJ) and T 1 and T2 percentages (PFCMJ% T 1 r = 0.457, PFSJ-%Tl r = 0.474). PP (CMJ and SJ) and the lRM followed a similar non-significant trend. No significant differences were found in Rf for Tl (TlRf) or T2 between the groups. However, TlRf had a significant negative correlation to PVCMJ, PVSJ, JHCMJ and JHSJ (r = 0.497, -0.473, -0.417, -0.456, respectively). This investigation has shown that there is a differential expression of titin protein bands in competitive athletes in comparison to untrained non-athletic individuals and that a relationship exists between titin protein band expression and variables associated with muscle strength and power.
Experiment Three
The Effect of Heavy Versus Light Load Jump Squats on the Development of Strength, Power and Speed
The purpose of this investigation was to examine the effect of an eight week training program with heavy versus light load jump squats on various physical performance measures and electromyography (EMG). Twenty-six athletic males with varying levels of resistance training experience performed sessions of jump squats with either 30% (JS30, n = 9) or 80% (JS80, n = 10) of their one repetition maximum in the squat (lRM) or served as a control (C, n = 7). An agility test, 20 metre sprint and jump squats with 30% (30J), 55% (55J) and 80% (80J) of their lRM were performed before (Pre) and after (Post) training. Peak force (PF), peak velocity (PV), peak power (PP) and jump height (JH) were calculated for all jumps based on force plate and displacement measurements. Average EMG was determined for the concentric phase of the lRM and jump squats for the vastus lateralis muscle at Pre and Post. There were significant increases in PP and PV in the 30J, 55J and 80J for the JS30 group (p:5:0.05). The JS30 group also significantly increased in the lRM with a trend towards improved 20 metre sprint times. In contrast, the JS80 group significantly increased both PF and PP in the 55J and 80J and significantly increased in the lRM but ran significantly slower in the 20 metre sprint. A significant increase in average EMG during the concentric phase of the 55J, 80J and lRM occurred in the JS80 group. Significant increases in muscle activity during the concentric phase of the 30J, 55J, 80J and lRM occurred in the JS30 group. No significant changes in EMG were observed in the C group. In the 30J the JS30 groups percentage change in EMG activity was significantly different from the C group. In the 80J the JS80 groups percentage change in EMG activity was significantly different from the C group. Changes in muscle activity coincided with improvements primarily in force in the JS80 group and changes primarily in velocity in the JS30 group. This investigation indicates that training with light load jump squats results in increased movement velocity capabilities. However, while training with heavy load jump squats increases force and power performance, it seems, in an acute situation, to hinder movement velocity and subsequent performance in high velocity activities (i.e. jumping with body weight, sprinting). It appears that velocity-specific changes in muscle activity may play a key role in changes in muscle strength and power.
Experiment Four
The Effect of Explosive Resistance Training on Titin, Muscle Fibre Type Distribution and Stretch-Shorten Cycle Performance
The purpose of this investigation was to examine the effect of heavy versus light load jump squats on variables relating to muscular function. Some of the twenty-five male subjects in this study trained for eight weeks performing either heavy (80% of one repetition maximum strength (lRM)) (JS80, n = 9) or light (30% of the lRM) (JS30, n = 9) load jump squats. The remaining subjects served as controls (C, n = 7). Subjects were tested before (Pre) and after (Post) training for performance in a countermovement jump (CMJ) and a static jump (SJ). Peak force (PF), peak power (PP), peak velocity (PV) and jump height (JH) were calculated for the CMJ and SJ from force plate and position transducer measurements. Muscle biopsies were obtained at Pre and Post training for analysis of titin and fibre type distribution. Gel electrophoresis was used for analyses of muscle samples. Titin-1 (Tl) and titin-2 (T2) protein bands were identified, quantified and expressed relative to each other. In addition the relative mobility (Rf) of Tl and T2 was determined as an estimate of molecular weight. Histochemical analysis was used to determine fibre type distribution for type I, IIA and IlB muscle fibres. The JS80 group significantly increased in PF and PP in the SJ from Pre to Post. However, no significant changes in PF, PP, PV or JH were observed from Pre to Post in any of the groups for the CMJ. Random patterns of significant differences in PF, PP, PV and JH between the CMJ and SJ were observed in all three groups. No significant differences were observed in Tl and T2 percentage or Rf from Pre to Post. In addition, there were no significant differences in fibre type distribution from Pre to Post. Low volume short term explosive resistance training for muscle power does not appear to result in any clear pattern of change in either titin or fibre type characteristics. However, heavy load explosive resistance training appears to result in a differential effect between improving SJ versus CMJ performance.
Details
- Title
- The relationship between different protocols of resistance exercise and the development of muscle power: implications for muscular and neural adaptation
- Creators
- Jeffrey Michael McBride
- Contributors
- Robert Newton (Supervisor) - Southern Cross UniversityAllan Davie (Supervisor) - Southern Cross University
- Awarding Institution
- Southern Cross University; Doctor of Philosophy (PhD)
- Theses
- Doctor of Philosophy (PhD), Southern Cross University
- Publisher
- Southern Cross University, School of Exercise Science and Sports Management
- Number of pages
- xxii, 188
- Identifiers
- 991012960200502368
- Copyright
- © Jeffrey M McBride 1998
- Academic Unit
- School of Health and Human Sciences
- Resource Type
- Thesis