The purposes of the study were: (i) to determine if the recovery rate of ice hockey players is affected by elevation of the legs, massage, and controlled breathing; (ii) to determine the length of recovery time needed for a one-half, one, and one and one-half minute skating period; and (iii) to compare the subjective recovery time with the calculated recovery half-time. One junior varsity and three varsity ice hockey players at the University of British Columbia began the study six weeks after the hockey training season began. Two subjects acted as controls and two subjects acted as experimentals. The testing of both the experimentals and controls was done in three parts. The first part consisted of one-half minute skates, the second part one minute skates, and the third part one and one-half minute skates. Each subject took four separate days to complete each part. On each day he repeated the prescribed skate three times, with rest periods of four and one-half minutes between skates, and a five minute rest period before the first skate. The control group recovered in the normal sitting position for each of the three parts of the experiment, while the experimental group varied the method of recovery using the normal sitting position, massage, elevation of the legs and controlled breathing in each of the three parts of the experiment. The control group was used to determine recovery times in the normal sitting position and to determine if there was any progressive improvement in the recovery time due to conditioning. The subjects also made a subjective estimate of when they felt they had recovered. The study found that there was no pattern of improving recovery times with the two control subjects. The mean recovery half-times ranged from: fifty-three seconds to one minute and forty-two seconds for the one-half minute skate; one minute and nine seconds to one minute and forty-eight seconds for the one minute skate; and one minute and eighteen seconds to two minutes and twelve seconds for the one and one-half minute skate. In every skating session with the two experimental subjects, elevation of the legs produced the lowest mean recovery half-times of the four different recovery methods. Subjects L.B. and K.M. both showed a significant difference between the mean recovery half-times of the normal sitting and elevation of the legs at the five per cent level of confidence for the one-half minute skates and subject K.M. showed a significant difference at the five per cent level of confidence in the one and one-half minute skate. The controlled breathing method of recovery produced mean recovery half-times that were lower than normal sitting mean recovery half-times in every skating period. However, the mean recovery half-times for controlled breathing were not as low as the mean recovery half-times for elevation of the legs. The massage method of recovery produced greater mean recovery half-times compared to the normal sitting recovery method in each skating time period with only one exception. In all skating sessions with one exception, the third trial recovery half-time was greater than the first trial recovery half-time. Generally, the subjective recovery times were closer to the calculated recovery half-times with the one-half and one minute skates than with the one and one-half minute skates. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

This study was designed to test the hypothesis that the electromyographic signal recorded from a working muscle reflects changes in blood lactate concentrations. A group of trained cyclists performed two incremental exercise tests on a cycle ergometer. The Control Trial was a incremental test with power increments of 23.5 watts per minute. Cadence was monitored and maintained at 90+/-1 revolutions per minute. The Experimental Trial consisted of a high intensity arm exercise protocol designed to elevate blood lactate above 8 mmol/1. The arm protocol was followed by five minutes of rest and the incremental exercise protocol used in the Control Trial. Expired gases were sampled every fifteen seconds and calculated values for oxygen uptake, ventilation, excess CO₂, and R.Q. were averaged to give a mean value for each minute in both trials. Heart rate was monitored and recorded every minute for both trials. Electromyographic data were sampled from the vastus lateralis of the right leg for the final eight seconds of each workload in both trials. The data were integrated for each pedal cycle and averaged to give a mean integrated value for each cycle (CIEMG) for each workload. During both trials blood samples were drawn from the cephalic vein of the left arm during the last ten seconds of each workload. The anaerobic threshold (Tlac) was determined using the log-log transformation as outlined by Beaver et al., (1985). Control Trial lactate concentration showed a marked inflection point after an initial slow increase. The mean maximal lactate concentration was 18.21 +/- 5.54 in the Control Trials. This inflection point occurred at a mean lactate concentration of 5.58 +/- 1.05 mmol/1. The mean oxygen uptake at the inflection point was 2.28 +/- 0.37 1/min which represented a mean of 72.6 +/- 7.20 % of maximum. Experimental Trial mean plasma lactate at the beginning of incremental exercise was 26.61 +/- 8.86 mmol/1. The plasma lactate concentration decreased steadily for the initial loads to a mean low concentration of 10.78 +/- 5.78 mmol/1 at Tlac and then increased to a mean of 19.08 +/- 6.66 mmol/1 at test completion. Plasma lactate concentration was greater in the Experimental Trial at all workloads though the values tended to converge once Tlac was surpassed. No visually identifiable inflection point in the plot of CIEMG vs Power could be determined in any of the plots. An analysis of the slope of the CIEMG vs. Power relationship was therefore performed. An analysis of variance demonstrated no significant difference in the slope of the relationship within or between trials in three different comparisons. The slope of the line was not statistically different when compared over: (a) the entire sample (b) pre Tlac and (c) post Tlac. Correlations performed between plasma lactate concentrations and CIEMG were significant in five of six subjects during the Control Trial (r = 0.57 to 0.97). During the Experimental Trial only three of the six subjects showed significant correlations and they were in the opposite direction (r = -0.62 to -0.96). Correlations between power output and CIEMG were for all subjects in both trials (r = 0.92 to 0.99 Control, r = 0.91 to 0.99 Experimental). The increase seen in CIEMG with increased power output reflects poorly the changes in blood lactate concentrations under the conditions of this investigation. Plasma lactate showed a dramatic increase in the Control Trial and a steady decrease from an initial high concentration followed by a marked increase in the final workloads of the Experimental Trial. In contrast the CIEMG increased in a near linear fashion for all subjects in both trials. The changes in CIEMG showed highly significant correlations with changes in VO₂ or power output in both trials for all subjects. These results indicate that changes in the surface electromyogram are highly related to changes in power output. However the surface electromyogram changes are not driven by changes in lactate concentration under the conditions of this investigation and may not be a sensitive enough indicator of these changes to be employed in the determination of Tlac. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

The purpose of this study was to investigate on a beat-by-beat basis, the nature of the instantaneous cardioacceleration resulting from short-duration, high-intensity, isometric contractions; to determine the relationship between relative muscular tension and cycle time, actual change in cycle time and relative change in cycle time; and to determine the effect of short-duration, high-intensity, isometric contractions on the recovery rate of cycle time. Muscular tensions and electrocardiograms were recorded before, during and after the isometric task and relative muscular tension, cycle time, actual change in cycle time and relative change in cycle time were calculated from these recordings. The sample population consisted of thirty university males. Each subject was randomly assigned to one of three groups. The task consisted of either a 50% MVC, 75% MVC or 100% MVC to be held for 10-seconds. Dynamometer and ECG recordings were monitered for the 15-seconds immediately before the contraction, the 10-seconds during the contraction and the 15-seconds immediately following the contraction. The hypotheses were: at the onset of an isometric contraction, the initial rate of increase of the relative change in cycle time is directly related to the magnitude of the percent maximal voluntary contraction; during the isometric contraction, the relative muscular tension is more closely related to the relative change in cycle time than either cycle time or actual change in cycle time; and, upon release of the isometric contraction, the initial rate of decrease of the relative change in cycle time is directly related to the magnitude of the percent maximal voluntary contraction. The trend analysis of the relative change in cycle time, during contraction, indicated that the linear and quadratic trends were different between the three groups. However, trend analyses of paired comparisons between the three groups indicated that the trends of the 50% MVC and 75% MVC groups were significantly different from the trend of the 100% MVC group, but, were not significantly different from each other. The post-hoc Newman-Keuls analysis indicated that the heart responded differently over the first five beats than over the last five beats, suggesting that there are at least two phases in the cardio-acceleratory response to isometric contractions and these two phases may be a result of a central and a peripheral heart-trigger mechanism. The trend analysis of the relative change in cycle time, during recovery, indicated a significant linear trend in beats with a significant difference in this trend between groups. However, observation of the graphic plot of means indicated that the data did not support the hypothesis, that the initial rate of decrease of relative change in cycle time was directly related to the magnitude of the %MVC. The non-support may have been due to the masking effect of respiration. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

Twenty male volunteers, comprising four distinct sub-samples (S=800m runners; R=varsity oarsmen; M=marathon runners; UT=untrained controls), participated in this study. They were made aware of the potential risks involved and informed consent was obtained. Anthropometric (hydrostatic weighing), physical characteristic and pulmonary function (Collins Respirometer) were assessed by standard techniques. Maximal oxygen consumption was determined on a progressive treadmill run (0.22 m.s⁻¹ every minute; initial speed 2.22 m.s⁻¹) to fatigue. Respiratory gases were monitered every 15 seconds (Beckman Metabolic Measurement Cart) with the four highest consecutive oxygen uptake values being averaged for determination of maximal oxygen uptake. Anaerobic performance (AST) was assessed as the time to fatigue the constant workload treadmill run at 3.52 m.s⁻¹, 20 percent incline. Post exercise blood lactate levels (HLa) were determined as an additional variable in assessment of anaerobic capacity. The M were significantly older than the other 3 groups while no significant differences existed between the trained groups for maximal oxygen uptake values. The S and R demonstrated significantly elevated AST (p<.01) and post-AST HLa (p<.05) levels above the M, whose values were similiar to the UT. This enhanced anaerobic performance could not be attributed to physical characteristic, pulmonary function or aerobic capacity differences of the trained athletes. Post-AST HLa displayed a significant relationship to anaerobic performance (r=.90). An enhanced lactate efflux mechanism was shown by the trained groups, which was not altered by training specificity. Muscle biopsies obtained at rest from the vastus lateralis muscle, were examined for fiber composition, pH, histidine and carnosine levels and buffer capacity (B). B was found to be elevated in the anaerobicly trained groups (p<.01) demonstrating a significant relationship to AST (r=.51) and fast-twitch fiber percentage (FT%; r=.51), which implied a relationship to muscle glycolytic capacity. Within the S and R, carnosine levels were found to be significantly elevated (p<.01), illustrating a significant correlation to B (r=.64) and FT% (r=.46), which emphasized the importance of carnosine as a physiological buffer and its possible relationship to the glycolytic capacity of the tissue. No differences in histidine levels or resting intramuscular pH were demonstrated with training specificity. These results suggest that the enhanced anaerobic performance could partially be attributed to elevated B and carnosine levels demonstrated within skeletal muscle subjected to anaerobic training. This may be due to the tissues enhanced capacities to seqestor the protons which accumulate during anaerobic glycolysis. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

Aim: The aim of this thesis was to contribute to a better understanding of heart rate during exercise with the aim of improving the precision with which heart rate can be used to measure intensity during running. Accordingly, heart rate responses were examined in long distance runners during different types of training and racing. The thesis also examined the effects of environmental and body temperature on heart rate during submaximal and maximal running. Study 1: Ten male provincial and national class road runners (VO₂max = 67.1 ± 3.8 mlO₂.kg⁻¹. min⁻¹) were recruited for the study. All the subjects completed questionnaires on their training history and recorded their training sessions in their diaries. The subjects wore heart rate monitors during training and racing. There was no convincing evidence that competitive runners who train at higher intensities have a better running performance. A poor relationship was found between %VO₂max and %HRmax. Finally, heart rate during races was higher compared to heart rates during training. The cause of the elevated heart rate during races was not clear. Study 2: The relationship between heart rate and running speed during competition was not well understood. Accordingly, an elite long distance male runner (25 years, VO₂max = 71 mlO₂.kg⁻¹. min⁻¹) was studied over a 5-month period during which time he participated in 9 races (5 km - 28 km). The subject wore a heart rate monitor which measured his heart rate throughout the race and his split running times each kilometre. The subject underwent a field test during which the heart rate/running speed relationship was determined under non-competitive conditions (r = 0.99). However, in the race situation there was no relationship between heart rate and running speed (r = 0.02). It was concluded that during competition there was no relationship between heart rate and running speed, whereas in a non-competitive situation heart rate was proportional to running intensity. Study 3: With a poor relationship found between heart rate and running speed during races in the previous study, other factors like environmental conditions and core temperature were hypothesised to have effects on heart rate. Accordingly, twelve highly trained distance runners were recruited for the study. Each subject ran on a treadmill (30 minutes at 70% peak treadmill running speed, followed by 8 km time trial) in different ambient temperatures (15°C, 25°C and 35°C) with humidity (60%) and wind speed (15 km.h⁻¹) kept constant. Heart rate, RPE and Tre were recorded every 5 minutes during the submaximal and the maximal trials. When subjects were exercising at 70% of peak treadmill running speed at 15°C, no cardiovascular drift was observed, at least for 30 minutes. However, during the same exercise test at 25 °C and 35°C there was a significant increase in heart rate. In the maximal exercise test the average heart rate was significantly higher during the trial at 35°C compared to the trials at 15° C and 25° C. It was concluded that heart rate can be used as an accurate measure of running intensity in cooler (15 ° C) ambient temperature. In summary, this thesis described the practical use of heart rate monitors during training and competition and at different temperatures. Data are provided which suggest that heart rate can accurately assess exercise intensity providing factors which affect the heart rate/running speed relationship are controlled.

Introduction Rugby Union (hereinafter referred to as ‘rugby’) is a contact sport with players being exposed to repetitive collisions throughout a match. As the risk of injury is relatively high, incidence surveillance studies within rugby has become popular. However most of the studies have focussed on senior players. The data on injuries among youth rugby players are limited. This makes it difficult to develop the game to make it safer for youth of all ages. Objectives The first objective of this study was to establish if any injury trends exist across different ages of youth rugby players (13 to 18 years). The second objective was to determine the patterns of injuries changed over four years (2011 to 2014). Methods The South African Rugby Union (SA Rugby) hosts four local youth tournaments annually to for local rugby talent: Craven Week under-13, Grant Khomo under-16, Academy Week under-18 and Craven Week under-18. Injury data were collected from the four SARU Youth Week Tournaments between 2011 and 2014. These data were compiled into one central SARU injury surveillance database. Injury categories were used to group data: ‘Type’, ‘Location’, ‘Event’ and ‘Severity’ of injury were assessed. Injuries were defined as either ‘Time-loss’ (those injuries that prevented a player from match participation for one or more days), or ‘Medical attention’ (injuries that required the player to seek medical attention at the time of or after injury but were not required to miss a match). Injury rates were represented by injury incidence densities (IIDs) (corresponding 95% confidence intervals (95% CIs) for IID were calculated for the number of injuries regardless of whether one person was injured more than once) per 1000 hours of match play. Incidence densities were considered to be significantly different from each other if their 95% CIs did not overlap and using Poisson regression analysis. Results The ‘overall’ combined IID across all four years was 54.6 injuries per 1000 hours of match play (95%CI: 51.0-58.2). The combined ‘time-loss’ IID was 18.9 injuries per 1000 hours of match play (95%CI: 16.8-21.0). ‘Time-loss’ injuries were greatest in 2011 (23.2 per 1000 match hours (95% CI: 18.5-28.0)). However, ‘time-loss’ injuries rates were significantly reduced in 2013, when compared to these injury rates in 2011 (13.3 (9.7-17.0). Craven Week under-13 presented significantly greater ‘overall’ injury incidence densities when compared to the older age groups (71.9 per 1000 match hours (95% CI: 62.4-81.4)). Overall, joint/ligament/tendon injuries were most common ‘overall’ and ‘time-loss’ injury sustained by players between 2011 and 2014 (30% and 33% respectively). This was followed closely by concussion injuries, which accounted for 29% of ‘time-loss’ and 12% of ‘overall’ injuries. A large proportion of both ‘overall’ (57%) and ‘time-loss’ (55%) injuries occurred during the tackle event, with the tackler being injured more often than the ball-carrier (37% and 18% respectively). However, there were no statistically significant differences when comparing ‘overall’ and ‘time-loss’ IID between the different tournaments from 2011 until 2014. Discussion Significant differences were found when comparing ‘overall’ and ‘time-loss’ IID between the different tournaments from 2011 until 2014. Craven Week under-13 presented significantly greater ‘overall’ injury incidence densities. This finding contradicts previous literature within youth rugby research. The tackle (combination of tackler and ball-carrier) still accounts for the highest proportion both ‘time-loss’ and ‘overall’ injury events (57% and 55% respectively). This is in accordance with previous studies. However, a point of concern was that concussion accounted for 29% of all ‘time-loss’ injuries and 12% of all ‘overall’ injuries. This finding suggests a gradual increase in the number of concussions suffered during the SARU Youth Week Tournaments between 2011 and 2014. Further research is required to determine the reason for this pattern. Conclusion Further research within youth rugby cohorts is required to determine the risk associated with involvement at various level of participation. Injury prevention programs should place focus on reducing the prevalence of concussion at youth level by educating players and coaches about safe tackle techniques. Future studies should focus on local youth cohorts for seasonal

Includes bibliographical references / The studies described in this thesis were the first to investigate in - depth body composition, exercise performance and neuromuscular characteristics of elite Paralympic athletes with cerebral palsy (CP). In the first study, in - depth whole body and site specific body composition was investigated in six athletes with CP using dual - energy x - ray absorptiometry. There were no differences between non - affected and affected sides with respect to bone mineral density and fat mass. Fat free soft tissue mass was lower on the affected side in bot h upper and lower limbs of the athletes. The novel findings of this study provided the first insight into anthropometric and bone physiology of elite Paralympic athletes with CP, and the possible residual effect of CP in these individuals. In the second study, five athletes with CP and 16 able - bodied (AB) age and performance matched controls performed a 30 second Wingate sprint cycle test. Power output was significantly higher in the AB group, although fatigue indices were statistically similar between groups. Muscle activity changed similarly in all muscle groups tested, in both affected and non - affected sides, in both CP and AB groups. However, certain neuromuscular irregularities were identified in the CP group. The similarity in fatigue profile was a novel finding. It was proposed that this similarity in fatigue was the result of long term high level athletic training required for Paralympic competition. Study three tested the similarity in fatigue between CP and AB athletes (that was described in the second study), using an externally paced fatiguing running trial. Six athletes with CP and 12 AB athletes performed one 40 m sprint test and vertical jump tests off both legs, the affected leg individually and the non - affected leg individually, before and after an adapted multistage shuttle run test to exhaustion. The 40 m sprint test, vertical jump off both legs and vertical jump off the affected leg were significantly compromised in the CP group, while vertical jump off the non - affected leg was similar between groups. Both groups fatigued similarly with regard to performance and muscle activity. The third study's finding s generally supported those of the second study. However, it was shown that although athletes with CP may represent a group of individuals who have achieved maximal physiological adaptation toward AB levels, the activity generated by both legs was performed towards the capacity of the affected leg. Study four attempted to elucidate explanations for the novel findings in studies 2 and 3 through investigation of pacing strategies employed by these athletes. Six athletes with CP and 13 AB athletes performed two trials of eight sets of ten shuttles (totalling 1600 m). One trial was distance deceived and the other was non distance deceived. The CP group ran slower than the AB group in both trials, and differences in pacing were observed in the deceived trial in the CP group. This novel study provided evidence for a possible pacing strategy underlying the exercise performance and fatigue profiles observed in the athletes with CP documented in the previous studies. The work described in this thesis lends novel insights and understanding to the physiology and physiological adaptations of highly functioning ambulant athletes with CP. The findings might have important implications with respect to the understanding of rehabilitation, coaching and clinical management of individuals with CP.

Static stretching is commonly performed by athletes and clinicians on the assumption that it increases joint range of motion (ROM). However, observations from our laboratory indicate that there is an apparent inter-individual variance in the change in ROM in response to static stretching. Furthermore, prolonged repetitive loading has also been shown to affect ROM of a joint or series of joints. In particular, runners have a significantly decreased hamstring ROM. The aim of this study was to investigate the factors which are associated with a change in ROM in response to 1) a static stretch session and 2) prolonged repetitive loading. The findings showed that there is a variable response in the change in ROM following both a SSS intervention and in response to participation in a 42.2 or 56 km road race. More specifically, about 10% of the participants had a reduction in ROM after the SSS while the majority of participants had a reduced ROM after completing the marathon or ultra marathon.

The overarching purpose of this study was to investigate the multifactorial aetiology of Achilles tendinopathy. Variables such as training and injury history, lower limb alignment, running biomechanics and movement variability were investigated. This study also aims to understand how different sensory inputs, such as shoe or pain may affect biomechanics. Thirty four uninjured runners (UN) and twenty one runners with Achilles tendinopathy (AT) composed the population sample for this study. Questionnaire and lower limb measurements were used to investigate the multifactorial aetiology of the injury. Selected kinetic, kinematic and muscle activity parameters were employed to analyse the biomechanics aetiology of the injury. Runners performed 10 running trials at a self-selected speed in two running shoes with different hardness. Additionally, the UN runners ran for 10 min on the treadmill while the AT runners ran on the treadmill until they developed pain in the Achilles tendon. The results of the study showed that AT runners have a higher incidence of previous injury, run for more years, have reduced hamstring flexibility, and are heavier and taller than uninjured runners. The study also showed a reduced integrated electromyography activity (IEMG) of tibialis anterior and rectus femoris in the AT group during the running cycle. Stride to stride variability was similar between UN and AT runners but the biomechanics variability between participants were lower for the AT runners. No specific biomechanical adaptations were found between the two different shoe conditions (soft vs. hard). Similarly, biomechanics parameters were not altered at the onset of pain, but the reduced IEMG activity of tibialis anterior and rectus femoris were presented before and during the pain condition. It can, therefore, be concluded that runners with Achilles tendinopathy present reduced muscle activity during running which may be either a novel aetiological factor, or an adaptive response to the injury. The lower variability between runners with AT may indicate that these runners are less able to adjust their biomechanics according to their different functional behaviour or external input signals but this may require further investigation. Finally, it can also be concluded that the sensory inputs such as shoes and pain do not change this muscle activity pattern.

Includes abstract. / Includes bibliographical references (p. 139-178). / This thesis examines the regulation of muscle function following exercise-induced muscle damage (EIMD), in an attempt to determine whether regulation occurs primarily in the muscle (neuromuscular) or further upstream. Upstream regulation has been hypothesized to occur in the lower brain structures, but one may assume that the efferent output to the muscle should be guided by the motor and pre-motor cortex alongside other associated cortical areas.