Background: Epidemiological studies have demonstrated higher ACL injury rates in female athletes when compared to males involved in the same sport. A recent meta-analysis of ACL injury prevention programs found that technique training was a common component of programs that were successful in reducing ACL injury. Purpose: The primary purpose was to determine the immediate and long-term effects of technique training aimed at minimizing medial knee displacement during jump-landings in female recreational athletes. The secondary purpose was to determine if any transfer of skill occurred as a result of our technique training. Study Design: Controlled laboratory study. Methods: A total of 26 participants who presented with medial knee displacement during a basketball rebound screening task completed the study protocol. Participants were randomly assigned to two groups (experimental and control groups, 13 each). The experimental groups received jump landing instructions aimed at minimizing medial knee displacement. The control group received "sham" training consisting of jump training for maximum height. Baseline motion analyses of participants performing a basketball rebound task were performed prior to participants receiving technique training. Immediate and delayed retentions tests were performed after the initial instructional session and after home-based training. Additionally, motion analyses were also performed on a stop-jump task during the baseline assessment and the delayed retention test to help in determining if any transfer occurred. Results: The initial instructional session resulted in increased knee excursion and reduced peak knee adduction moments in the experimental group. Following home-based training, the experimental group continued to exhibit increased knee excursion along with decreased landing forces. No evidence of transfer was present following the initial training session or after home-based training. Conclusion: Our jump training instructions led to temporary changes, most notably increased knee excursion about the sagittal plane. No transfer of skill occurred as a result of our training. Clinical Relevance: Technique training instructions aimed at reducing medial knee displacement resulted in increased sagittal plane motion, but were unable to minimize medial knee displacement. ACL injury prevention programs may need to include a variety of drills, tasks, and sport-specific movements.

Purpose: To examine the relationship between hand rim propulsion power and energy expenditure during wheelchair locomotion. Methods: Fourteen individuals who used manual wheelchairs were included in this study. Each participant performed five different locomotion activities in a wheelchair with a PowerTap hub built into the rear wheel. The activities included wheeling on a level surface that elicited a low rolling resistance at three different speeds (4.5, 5.5, and 6.5 km∙hr-1), wheeling on a rubberized 400m track that elicited a higher rolling resistance at one speed (5.5 km∙hr-1), and wheeling on a sidewalk course that included uphill and downhill segments at their self-selected speed. Energy expenditure was measured using a portable indirect calorimetry system. In addition, each subject wore an Actical and a SenseWear activity monitor on the right wrist and upper arm, respectively. Stepwise, linear regression was performed to predict energy expenditure from power output variables. A repeated measures ANOVA was used to compare the measured energy expenditure to the estimates from the power models, the Actical, and the SenseWear. Bland-Altman plots were used to assess the agreement between the criterion values and the predicted values. Results: The relationship between energy expenditure and power was significantly correlated (r = 0.694, p < 0.001). Stepwise, linear regression analysis yielded three significant prediction models utilizing measured power; measured power and speed; and measured power, speed, and heart rate. A repeated measures ANOVA demonstrated a significant main effect between measured energy expenditure and estimated energy expenditure (p < 0.01). There were no significant differences between the criterion method and the power models or the Actical. The SenseWear significantly overestimated energy expenditure when wheeling at 4.5 km·hr-1, 5.5 km·hr-1, 6.5 km·hr-1, and during self-paced sidewalk wheeling (p < 0.05). Conclusion: Energy expenditure can be accurately and precisely estimated based on wheelchair propulsion power. These results indicate that wheelchair power could be used as a method to assess physical activity in people who use wheelchairs.

This dissertation examines the history of the application of science to the training of elite runners through 1975. In particular, it details the changes that occurred in the ruling theories of training within the framework of what Thomas Kuhn, author of The Structure of Scientific Revolutions refers to as a “paradigm shift.” The quest for the origins of training began in ancient Greece where the earliest written histories of athletics were recorded. There, according to the sophist Philostratus, a rudimentary form of periodization (a process of structuring training into phases) was born. Examination of eighteenth and the bulk of nineteenth century training practices revealed little difference in the training of horses, fighting cocks, greyhounds, pugilists (boxers), and runners. In the lead up to WWI, training could be classified as “light,” where athletes stayed competitive with very little training. Athletic training between WWI and WWII was characterized by the advent of “moderate” training loads and the introduction of innovative training methods--fartlek and interval training. Arthur Lydiard’s recommendations of preliminary marathon training for distance runners (800- 10,000 meters) in the late 1950s, along with the training of Emil Zátopek, Peter Snell,and Jim Ryun, epitomized a transition from moderate to “heavy” training loads thatoccurred between 1945 and 1975. Meanwhile, other eminent coaches such as Payton Jordan of Stanford University and William Bowerman of the University of Oregon offered balance to the heavy volume training approach by emphasizing quality over quantity. Following WWII, in the battle for world ideological supremacy, the Soviet Union utilized sport as a political tool to demonstrate the superiority of its communist system. Integral to achieving the best sporting results was the application of “cutting edge” sport science and the advent of modern-day periodization. The first detailed English-language overview of Professor Lev Pavlovich Matveyev’s groundbreaking theory of periodization by Frank Dick of Great Britain in 1975 caused a major shift in the paradigm of planning an athlete’s training--so much so, that by the turn of the twenty-first century, periodization formed the foundation of most modern coaching theory and practice and the basis of every serious athlete’s training. / text

INTRODUCTION: Excessive hip adduction (HADD) has been associated with a number of lower extremity overuse injuries, and it has been suggested that it may be the result of reduced strength of the hip abduction musculature. Hip structure has been postulated to influence both hip abduction (HABD) strength and HADD. The purpose of this study was to investigate the relationship between hip structure, HABD strength, and frontal plane kinematics during running. METHODS: Peak isometric HABD strength, lower extremity kinematics, femoral neck-shaft angle (NSA), and pelvis width-femur length (pw-fl) ratio were recorded for 25 female subjects. Pearson correlations (P < .05) were performed between variables. RESULTS: A fair relationship was observed between femoral NSA and HABD strength (r = -.472 P = .017) where an increased NSA was associated with reduced HABD strength. No relationship was observed between HABD strength and frontal plane kinematics or between NSA/pw-fl and frontal plane kinematics. CONCLUSION: Alterations in the femoral NSA have the ability to influence peak isometric hip abduction strength. However, alterations in strength did not result in changes in lower extremity kinematics. Structural deviations at the hip do not appear to influence hip kinematics during running.

Approaches to the study of anxiety in sport have tended to rely on the use of questionnaires to assess levels of competitive anxiety. The development of the Competitive State Anxiety Inventory-2 (Martens et aI., 1982) has according to Jones (1995) led to considerable research investigating the relationship between anxiety and sport performance. Study 1 reported here utilised the CSAI-2 with an additional directional scale to examine individual differences and competitive state anxiety in sport. Results revealed that there were no significant differences (p<.05) between three achievement levels of competitive swimmers (n=89) for intensity scores, however, significant differences were found for cognitive anxiety and somatic anxiety directional scores across levels. Further, unexpected correlations between CSAI-2 intensity and directional scores for several items, highlighted the importance of considering individual differences in the interpretation of anxiety symptoms. Study 2 was based on Davidson and Schwartz's (1976) Matching Hypothesis which claims that interventions, to be effective, must be matched to the individual's dominant mode of experiencing anxiety. Female high level skaters (n=15) were assigned to a control group (n=5), a cognitive anxiety group or a somatic anxiety group based on interview data, CSAI-2 scores, coach reports, and performance at a simulated competitive event. Results revealed that there was no support for the Matching Hypothesis, and that greater attention should be devoted to using methods that allow for a more individualised approach to understanding anxiety in sport. A diary-based methodology incorporating Watson and Tellegen' s (1985) concept of mood, was employed in study 3 with high level Netballers (n=8) and Super League Rugby League Referees (n=8), to examine the relationships between anxiety, mood and sport and other life events for a 4 week period. Results suggested that this methodology can be used to allow data to be analysed ideographically and from an inter-individual basis as well, and helps to place sport anxiety into a broader context in relation to other mood states and life events. Finally, study 4 further developed the use of the diary based methodology by investigating the relationship between mood, anxiety and performance in International Student Rugby players (n=Il). Whilst no clear relationship was found between anxiety, mood states and match performance scores, several interesting findings revealed that much more could be achieved by re-directing focus at what anxiety means to an individual both before and after sport performance. The findings from the diary-based studies are discussed in terms of the need to address the meaning of anxiety in sport, in part, by drawing on the approach taken within existential-phenomenological psychology.

Thesis (Ph.D.)--University of North Carolina at Greensboro, 2007. / Title from PDF t.p. (viewed Mar. 3, 2008). Directed by Tom Martinek; submitted to the School of Health and Human Performance. Includes bibliographical references (p. 127-142).

Thesis (Ph. D.)--University of Idaho, 2006. / Abstract. "August 2006." Includes bibliographical references. Also available online in PDF format.

Training is a complex, multi-factorial process, which involves the manipulation of the duration, frequency and intensity of exercise. When quantifying the physiological and performance responses to training a large inter-individual variability in training responses is frequently observed. To date, the majority of research has examined the relationship between genetics and trainability. Another hypothesis, which has not been fully explored, is that the variability is also due to an inappropriate standardisation of exercise intensity or duration. This thesis, therefore, presents a series of studies that investigate the effects of individualised methods of prescribing exercise intensity and duration on performance and physiological responses in cycling. Study 1 compared time-to-exhaustion (TTE) to time-trial (TT) performances when the duration of the trials were matched and participants were blinded to feedback. A higher mean power output was found for TTE compared to TT at 80% (294 ± 44 W vs. 282 ± 43 W respectively, P < 0.05), but not at 100% (353 ± 62 W vs. 359 ± 74 W) and 105% (373 ± 63 W vs. 374 ± 61 W) of maximum aerobic power (MAP). Critical power (CP) calculated from the TTE trials was also higher, whereas, anaerobic work capacity (W′) was lower (P < 0.05). The findings favour TTE over TT performances for a higher mean power output and calculated CP. Study 2 compared the effects of three training intensities: moderate intensity (MOD), high intensity (HIT) and a combination of the two (MIX) when the duration of exercise was individualised. Participants were randomly assigned to one training group and trained 4 times per week for 4-weeks. Training duration was individualised to each participant’s maximum performance. All training groups increased maximal oxygen uptake (V̇O2max), MAP, TTE and gross efficiency (GE) after training (P < 0.05), but no differences were observed between groups (P > 0.05). Therefore, when the duration of training is individualised, similar improvements in performance and physiological responses are found, despite differences in exercise intensity. The CP and power law models propose power-duration relationships that describe maximum endurance capacity. Study 3 compared the predictive ability of these two models for TTE performances. It was hypothesised that the CP and power law models would reliably predict actual TTE for intensities between 80-110% MAP, but a power law model would better predict TTE for intensities outside of this range. No significant differences for parameter estimates were found between models (CP and power law) and actual TTE for intensities ranging from 80-110% MAP. Outside of this range however, the CP model over predicted actual performance at 60% and 150% MAP (P < 0.05), while there was no significant difference between the power law model and actual performance at these intensities (P > 0.05). Both models were different from actual performance at 200% MAP (P < 0.05). Therefore, a power law model can accurately predict cycling TTE for intensities ranging from 60-150% MAP. Study 4 tested the hypothesis that the inter-individual variability for TTE performances is due to the methods used to standardise exercise intensity. A %V̇O2max prescription was compared with an alternative based on an individual power-duration relationship (using a power law model). A power law model predicted the intensity for TTE lasting exactly 20-min and 3-min. A corresponding intensity for TTE as a %V̇O2max was 88% and 109%. On two separate occasions participants completed two TTE trials using the power law and %V̇O2max prescriptions, with 30-min rest between trials. There was a significant reduction in the inter-individual variability for TTE when exercise was prescribed using a 20-min power law versus 88% V̇O2max prescription method (coefficient of variation = 29.7 vs. 59.9% respectively; P < 0.05). However, there was no significant difference in the inter-individual variability for TTE using a 3-min power law versus 109% V̇O2max prescription method (P > 0.05). Two main conclusions can be drawn from this thesis. Firstly, a power law model can accurately predict and describe cycling endurance performance across a wide range of intensities. Secondly, prescribing exercise intensity using a power law model reduces the variability in TTE by 50% when compared to a %V̇O2max prescription method. Therefore, the methods used to standardise exercise intensity appear to be related to the variability in TTE performances. Future research should examine whether training prescribed using a power law model reduces the variability in subsequent training responses.

The performance of dynamic jumps is the result of complex interactions between many factors, including preflight characteristics, muscle strength and activation timings, and the elastic properties of external contact surfaces. The aim of this study was to determine the contributions of these factors to the performance of dynamic jumps and to gain a greater understanding of the underlying mechanics. Theoretical computer simulation models were developed incorporating muscle representations and elastic interfaces between the model and the external contact surfaces for vaulting and tumbling takeoffs in gymnastics. The simulation models were customised to represent the elite male gymnast analysed in this study by calculating subject specific inertia and muscle parameters from experimental testing with the gymnast. The simulation models were evaluated by comparing simulations of each movement with actual vaulting and tumbling performances by the elite male gymnast and then used to quantify the contributions to vaulting and tumbling performance. The characteristics of the preflight were found to have a major influence on both vaulting and tumbling performance, In addition, for tumbling, the takeoff strategy (activation timings of the muscles) was also crucial, with it being possible to produce a range of postflight performances by just changing the strategy used during the takeoff. Vaulting and tumbling performances were found to be relatively insensitive to changes (within realistic limits) in the elastic nature of the contact surfaces and for vaulting the elasticity of the shoulder joint had a considerable effect on performance. In addition the use of the hand/foot was found to prolong the duration of contact with an external surface.

The general problem was to determine if there was a significant relationship among collegiate swim team training methods, final team standings and individual team member’s placement by event in the 1976 NCAA Division I Swimming Championship Meet.