Dissertations / Theses on the topic 'Sprinting performance'

Salbutamol, an inhaled asthma medication, may have a number of extra-pulmonary effects throughout the body that may result in an ergogenic benefit during exercise. Purpose: To investigate the ergogenic effects of high-dose inhaled salbutamol on sprint performance following a prolonged, individualized, steady-state exercise bout; secondarily, to identify the systemic effects of salbutamol during steady-state exercise that might explain such an ergogenic finding. Methods: Using a eucapnic voluntary hyperpnoea test, ten male and ten female cyclists were tested for exercise-induced bronchoconstriction (EIB). Using a crossover design, participants inhaled either placebo or 1600g of salbutamol and subsequently completed two 75-minute constant power cycling bouts immediately followed by a 30-second Wingate test. Primary outcomes were those collected during the Wingate test: peak and mean power. Lactate, perceived exertion, ventilatory, and gas exchange measurements were collected throughout the steady-state bout. A repeated-measures ANOVA was utilized to assess the effects of sex, EIB status, and salbutamol on performance outcomes. Results: Lung function was improved following salbutamol inhalation (M = 8.3%, SD = 1.0%) compared to placebo (M = 1.0%, SD = 5.6%). The differences in peak and mean power between the salbutamol and placebo conditions were not found to be statistically significant. During the 75-minute endurance bout, carbohydrate utilization, heart rate, and minute ventilation were increased while ventilatory efficiency was decreased. In general, the effects of salbutamol were more pronounced in women relative to men, while no impactful differences were found as a function of EIB status. Conclusion: Despite inducing a possible increase in carbohydrate metabolism, salbutamol inhalation did not cause a significant increase in peak or mean power during a 30-second Wingate test.
Education, Faculty of
Kinesiology, School of
Graduate

Sprinting is a fundamental activity in many team sports such as soccer, rugby, football, field hockey, and basketball. Specifically, the ability to rapidly increase sprint running velocity over short distances, which is often referrcd to as sprint acceleration ability, is of major importance to team-sport athletes since sprint efforts during team-sport matches are typically of short duration (e.g., 10-20 m, 2-3 s). Biomechanical characteristics of the acceleration phase of sprinting has previously been studied in track sprinters from a block start, but there is a dearth of research exploring tile biomechanieal charactcristics of sprint acceleration in team-sport athletes from starting positions that are specific to team-sport match situations (e.g., standing start). In addition, resisted sprint training such as weighted sled towing is a popular training modality that athletes often use in an effort to improve sprint acceleration ability, but its use is largely based on choaches' observation and lacks experimental evidence. In particular, the optimal training load for resisted sprint training is currently unknown. This thesis explored to fill the research gap in such areas.

Post-activation potentiation (PAP) is the phenomenon where contractile history of a muscle may acutely increase voluntary performance of future contractions that are biomechanically similar (72). In order to exploit the PAP phenomenon, a conditioning activity (CA) is performed to enhance the performance of a subsequent skill. Throughout the literature, a common example of a CA is sets of heavy-loaded squats in order to potentiate subsequent jumping (31,33,39,57,83,116,151,163) or sprinting performance (15,28,39,99). Post-activation potentiation can be used either in a warm-up to acutely enhance performance for competition, or used within a resistance training session to enhance speed-strength, with the intention of producing a greater training stimulus for chronic adaptations. The major issue with the PAP literature is the inconsistent results from study to study. There are many examples within the research that show the positive effects of PAP (44,54,57,62,83,102,133,163), whilst many others have failed to find any increase in performance (42,47,56,81,112,123,141). The results have been inconsistent as the methodology between studies has varied dramatically. These differences include the warm-up used prior to testing sessions, changes in the type of CA (30,54,163), the intensity or load of the CA (19,21,33) and the rest period allocated between the CA and the performance of the skill. Furthermore, it seems that certain individuals respond better to a CA, with most of the literature suggesting that participant strength has a positive correlation with a potentiating response (15,31,44,116,128,129,163). Due to the vast differences in methodologies used throughout the potentiation literature, it is hard for coaches to identify the best practice in order to elicit a positive potentiating effect. Therefore, four studies were designed to address these current gaps within the potentiation literature in order to establish the best methodology to elicit a potentiating response. The first study sought to investigate whether a heavy half-squat CA could further improve jumping after an individualised optimal warm-up. As many of the warm-ups used prior to the baseline measurement in the potentiation research have been insufficient (30,44,69,71,88,102,111,115,140,143,158), it is plausible to suggest that improvements after a CA could be due to general mechanisms of a warm-up, rather than PAP. To investigate this, participants performed six different volumes of warm-ups on six separate days, followed by CMJ and DJ testing. After each participant completed the six warm-ups, their individual optimum warm-up was identified as the warm-up that produced the greatest CMJ relative peak power (RPP). On two separate sessions, a CA of four half-squats at a 5RM load was then added to each individual’s optimum warm-up and a sub-optimum warm-up. Countermovement jump tests were performed before the CA (pre) and then four and eight minutes after the CA. Drop jump testing was performed before the CA (pre) and then six and 10 minutes after the CA. When examining each post-test separately, no improvements in CMJ performance were identified. Furthermore, for both the optimum and sub-optimum warm-up conditions, DJ performance significantly decreased at all post-tests (p < 0.05). When each individuals best recovery period was considered (post-best), both the maximum and mean CMJ jump height significantly increased above baseline measures for the optimum warm-up condition. No other CMJ or DJ variable displayed any significant change after the addition of the CA for either condition. As significant increases in CMJ jump height were identified, the four half-squat CA with a 5RM load was used in the next investigation. Although each individual’s optimum warm-up volume varied, the moderate warm-up volume produced sufficient CMJ performance for all individuals. Considering the time required identifying each individuals optimum warm-up, the moderate warm-up was deemed sufficient and was used for the following studies. The second study of this thesis investigated the acute response of two different CA strategies. Both CAs included four half squats at a 5RM load, however, in one condition participants were instructed to perform the squat in a controlled manner, whilst in the second condition, they were instructed to lift the bar as fast as possible without losing contact with the ground. At any post-time (including post-best), no significant improvement were identified for any CMJ variable in either condition. Furthermore, DJ performance significantly decreased at all post-tests for the explosive CA condition. Although no significant improvements were identified, when each individual’s optimum recovery period was considered, CMJ jump height increased by 2.6% in the explosive CA condition, as opposed to 0.9% in the controlled CA condition. Because of this difference within the means of each condition, for the future studies throughout this thesis, participants were instructed to lift the bar as fast as possible during a heavy half-squat CA. The third study of this thesis compared different volumes of plyometric CAs (rebound jumps) to a CA involving heavy half-squats and assessed the effect each had on potentiating CMJ and sprinting performance. Past research had often used small amounts of plyometric contacts to potentiate future contractions (23,30,143,146,151), however, due to their short duration; they were often not successful in improving performance. For one condition, this study increased the repetitions of plyometric contacts in the CA, so that its duration matched the time under tension exhibited by the four half-squats with a 5RM load. Furthermore, two other plyometric CA conditions were included; one that matched half of the time under tension of the half-squats and one that involved only four repetitions of the rebound jump (match the amount of repetitions of the half-squat). No CA (plyometric or half-squat) displayed statistical significant improvements in CMJ or sprint performance at any post-test interval. For CMJ performance, although it did not significantly improve performance, generally the heavy half-squat CA had smaller decrements in performance than the plyometric CAs, hence the final investigation of this thesis focussed upon different heavy dynamic CAs in order to potentiate CMJ performance. The final study of this thesis firstly aimed to investigate the effect of three different types of half-squat CAs had on potentiating CMJ performance. This study also aimed to explore why certain individuals respond positively to a CA, whilst others respond in a negative manner. At the beginning of this study, participants completed a number of fitness performance tests, to assess each individual’s performance. Participants then assessed the effect of three different CAs on CMJ performance. These CAs included three repetitions of the half-squat with a 3RM load (3 @ 3RM), four repetitions with a 5RM load (4 @ 5RM) and then five repetitions with a 5RM load (5 @ 5RM). In terms of the entire population of the study, after each of the CAs, post-CMJ performance typically decreased across all rest periods, whilst any improvement in particular CMJ variables were considered to only be trivial in terms of effect size magnitudes. Despite this, multiple statistically significant positive correlations were evident between particular fitness qualities (absolute strength, CMJ RPP and aerobic capacity) and the change scores between pre and post-best CMJ performance after certain CAs. Therefore, the participants were median split in terms of each of the following fitness qualities to assess the relationship each quality has on potentiating CMJ performance. When the population was split in terms of absolute strength, the stronger participants significantly improved CMJ performance at their best recovery period after the performance of the 5 @ 5RM CA (three out of the four CMJ variables assessed significantly improved), whilst the weaker individuals showed no significant improvements. A similar trend was exhibited when the population was split in terms of CMJ RPP, with the more powerful individuals improving by small to moderate effect size magnitudes after the 5 @ 5RM CA, whilst the less powerful group did not. From the studies presented in the thesis, it can be concluded that certain recreationally resistance trained males can acutely enhance CMJ performance with the use of a heavy dynamic CA, even after pre-test performance has been optimised by a general warm-up. The optimum recovery period for the individual does need to be considered, as individuals require different amounts of rest to allow for an improvement in performance. Furthermore, the individual needs to have sufficient strength of the lower limbs in order to improve future contractions via the use of the heavy dynamic CA, as individuals with less strength do not improve post-CMJ performance after a CA. In terms of the type of CA used, heavy half-squat seem to be more effective than rebound jumps in order to potentiate CMJ performance. Furthermore, five repetitions with a 5RM load seems more effective than heavier CAs (3 @ 3RM) or ones that have less repetitions (4 @ 5RM) for this particular population.
Doctor of Philosophy

Aim: Fatigue during team sports requiring multiple sprints can result from the combined effects of metabolic, mechanical, neurological, and immune factors. The purpose of this study was to investigate the influence of capsaicin on performance of and the physiological response to an exercise test simulating the fitness demands of team sport game conditions. Methods: This study was a placebo-controlled, crossover design. Nineteen healthy male experienced athletes age 18-30 yr consumed either 3 g/d cayenne (25.8 mg/d capsaicin) or placebo for 1 wk. Directly following the supplementation period, they completed a repeated sprint test consisting of 15 30 m maximal effort sprints on 35 s intervals. Sprint times were recorded via electronic dual-beam timing system. Fasted blood draws for interleukin-6 (IL-6) were taken at baseline prior to supplementation, 45-min pretest, and immediately post test. Heart rate (HR), blood pressure (BP), rate of perceived exertion (RPE), muscle soreness (MS), and gastrointestinal distress (GD) were measured 1-min pretest, during, posttest, and 1-min posttest. MS was also measured for 3 d posttest. Results: Relative to the placebo, capsaicin significantly reduced maximum HR by 9.3%, total average HR by 8.5%, and sprinting average HR by 6.0% (P<0.05). Capsaicin caused GD of at least 2/5 in 24.5% of subjects. There was no difference between treatments in fastest or mean sprint time, fatigue, percent change or difference in IL-6, BP, RPE, sprint or posttest MS. Conclusion: Capsaicin did not influence repeated sprint performance or the inflammatory response, but reduced HR during intense activity and causes substantial GD.
Master of Science

Fifteen well-trained males, mid-thigh pull peak force (IPF 4403.61 ± 664.69N) and isometric peak force allometrically scaled (IPFa 226.04 ± 25.81) were assigned to two groups: repetition maximum training (RM) and relative intensity training (RI) for a twelve-week training intervention. The main effect of time showed a statistically significant difference in mean sprint performance and IPFa at the different time points (p < 0.001). There was a larger magnitude of within-subject effect with respect to sprint performance pre – post with the RI group (ES = 1.06, 7.19%) as compared to the RM group (ES = 0.567, 4.23%, p < 0.001), as well as a larger magnitude of within-subject effect with respect to IPFa pre – post with the RI group (ES = 0.426, 7.51%) as compared to the RM group (ES = 0.270, 13.29%). Furthermore, there was a non-statistically significant, moderate between-group difference in the change in IPFa from pre-post in favor of the RI group (ES=.75), and a large between-group difference in the change in sprint performance pre-post in favor of the RI group (ES=1.50). Results lead investigators to suggest the utilization of RI training tactics for the development of sprint performance when minimal sprint skill training is available.

The principal aim of the present thesis was to investigate the effect of increasing muscular strength on the co-ordination of movement during accelerative sprinting. Physically active males fro the University of Edinburgh participated in an 8-week resistance training study. Pre and post-training measures of 10 m and 20 m sprint time, maximum strength and explosive strength were taken. The first 3 strides of the 20 m sprint were videoed for further analysis. Changes in co-ordination were assessed using phase-plane diagrams and continuous relative phase (CRP) measures. The resistance training intervention resulted in a significant increase in maximum and explosive strength immediately following the training period, but sprint times were not improved. Increases in the vertical impulse, with concomitant decreases in the horizontal impulse were recorded following the training period. These changes caused a reduction in stride frequency. Although the resistance training increased muscular strength the control of the orientation of the ground reaction force with respect to the centre of mass (CoM), which has been identified as a specific constraint associated with the stance period of accelerative sprinting, was not adapted. The result of the present thesis demonstrates that an 8-week resistance training intervention increases muscular strength but does not improve accelerative sprint performance immediately following the training period. Sprint running performance is affected by the complex interaction of constraints associated with the task and the physical characteristics of the performer. Muscular strength has been identified as a characteristic that constrains the co-ordination of multi-joint movements. Considering the effect of resistance training on the control and co-ordination of multi-joint movements provides further insight into the effectiveness of potential training interventions, such as resistance training, and provides information for coaches to develop strategies to expedite the transfer of strength to accelerative sprinting.

There is evidence to suggest that the bending stiffness of footwear can be adapted to influence sprinting performance. In addition, it has been suggested that to achieve maximal performance, the mechanical properties of this footwear needs customising to an individual athlete. Due to a lack of detailed biomechanical data, the influence of longitudinal bending stiffness on the dynamics of the lower extremity during sprint running remains largely unexplained and is subject to considerable speculation. Thus, the aim of this work is to develop functional sprint footwear in a range of different longitudinal bending stiffnesses in order to explore the effects on measures of sprinting performance and lower extremity dynamics. Novel mechanical test procedures were developed and benchmark properties of current commercial sprint spikes were ascertained. Bending stiffness data showed considerable variability amongst those sprint spikes aimed at athletes of a higher competitive standard, which indicates that there is no consensus regarding optimum stiffness. A kinematic analysis of barefoot and shod sprinting was undertaken to investigate the influence of sprint footwear on lower extremity kinematics. Medial and lateral sagittal plane data were collected at the start and in the acceleration (10 m) and maximal speed (50 m) phases of a 100 m distance. Metatarsophalangeal joint (MPJ) angular range and velocity were significantly reduced in sprint spikes compared to barefoot conditions and the magnitude of the controlling affect was larger at 10 m compared to 50 m. Selective laser sintering of nylon was used to produce a number of sprint shoe sole units each of different thickness. These were attached to standard uppers to produce a range of longitudinal bending stiffnesses encompassing those already commercially available. The influence of shoe stiffness on sprinting perfonnance was assessed using specific jump metrics that were selected for use based on their high correlations with sprinting perfonnance during starting and maximal speed sprinting. Results indicated that sprint shoe longitudinal bending stiffness influenced the dynamics of the lower extremity during squat and bounce drop jumps. The relationship between maximal perfonnance and shoe stiffness was specific to the jump metric; best performance was achieved in intermediate stiffness shoes for the squat jumps and high stiffness for bounce drop jumps. Six bespoke pairs of sprint shoes with bending stiffness spanning and exceeding that of current commercial sprint spikes were developed. Results showed that MPJ and ankle joint dynamics were affected by longitudinal bending stiffness during squat and bounce drop jumps. Angular velocities of the MP and ankle joints were significantly reduced with increasing longitudinal bending stiffness. For the squat jump, ankle joint moments increased with shoe longitudinal bending stiffness and reached an individually optimal level within the stiffness range. This was also the case for ankle joint power and mechanical energy. The bounce drop jump saw mechanical energy generation at the MPJ increase with shoe longitudinal bending stiffness. Different levels of longitudinal bending stiffness were required for maximal performance in each jump type. This infers that sprint shoe bending stiffness requirements may vary according to the phase of the race. Furthermore, individual responses to different stiffnesses highlighted the importance of personalising mechanical properties to the requirements of a particular athlete for maximal performance. This research has focused on the use of discrete jump metrics to assess performance and therefore future work should aim to investigate the implications of different stiffness conditions using measures of actual sprinting. Also, further detailed musculoskeletal explorations are required in order to fully understand the precise mechanism by which longitudinal bending stiffness influences performance.

The purpose of this investigation was to determine the effect of 6 weeks of vertically- and horizontally-directed lower-body plyometric exercise with vertically versus horizontally biased ground force application, on 40-m sprint running time, vertical jumping height, body composition and gastrocnemius medialis (GM) muscle architecture. Male (n = 19) and female (n = 20) recreational athletes were recruited and stratified according to 40 m sprinting ability, then randomly allocated to one of two groups: horizontally-directed plyometric training (HT) and vertically-directed plyometric training (VT). The groups performed the experimental procedures twice each week with the same number of total ground contacts, while maintaining their usual weekly training load. During training the subjects performed bounding exercises with maximum effort with either a horizontal or vertical directional bias, depending on the allocated group. Sprinting performance was undertaken on an indoor, sprung-cork running track with the times recorded using infra-red timing gates recording to the nearest 0.01s. Ground reaction forces (GRFs) were recorded using in-ground, multi-component, peizo-electric force platforms. Changes in performance and muscle function were assessed during counter-movement jumps (CMJs), squat jumps (SJs), and depth jumps (DJs) from 0.20 m (reactive strength index (RSI-20)) and 0.40 m (RSI-40). Muscle fascicle length (FL) and angle pennation (AP) of the GM were assessed using ultrasonography, while dual-energy x-ray absorptiometry (DEXA) was used to determine body fat percentages (BF%) and composition of the shank of the subjects’ dominant legs (push-off leg during sprinting). Multivariate, repeated measures analyses of variance were used to determine differences between training groups and percentage of change scores were calculated for each variable. Both HT and VT presented statistically significant (p ≤ 0.05) with small-to-moderate standardised effect (d) improvements in 10-m (HT: d = 0.22; VT: d = 0.09), 20-m (HT: d = 0.20; VT: d = 0.15), 30-m (HT: d = 0.24; VT: d = 0.23) and 40-m (HT: d = 0.40; VT: d = 0.39) times, with no differences between the groups. No statistical change was seen for either experimental group at 5-m, however a small and trivial practical change was observed for HT (d = 0.20) and VT (d = 0.04) groups. Significant changes were observed for CMJ, SJ, RSI-20 and RSI-40 for both HT and VT groups, without a significant difference between groups. No significant or practical benefit in the change following training was observed for FL (HT: d = 0.02; VT: d = 0.05) or AP (HT: d = 0.04; VT: d = 0.08), with no between group significant differences. Following training significant changes in both experimental groups were observed for BF% (HT: d = 0.13; VT: d = 0.18) and total body mass (HT: d = 0.09; VT: d = 0.09), however there was no significant difference between groups. The outcomes suggest that HT and VT were similarly effective at improving sprinting and vertical jumping performance, in recreational athletes. The observed outcomes support the use of either movement-specific training paradigms or kinetically dissimilar exercises for the purpose of improving sprinting performance, even though greater forces may be applied.

The purpose of this dissertation was to investigate the influence of lower body strength characteristics on change of direction (COD) performance in NCAA Division I soccer athletes. Specifically, this dissertation served to examine: 1) whether the lower body strength and power were related to COD performance, 2) whether stronger athletes had superior COD performance than weaker athletes, 3) whether the force production asymmetry and strength dominant (SD) associated with COD performance, and 4) weather sex differences existed in kinetic variables during the stand phase of cutting. The major findings of this dissertation include: 1) strength and power characteristics were moderately to strongly related to COD performance. Furthermore, soccer athletes’ straight-line sprinting times were significantly related to COD performance outcomes. 2) Stronger athletes demonstrated the tendency to perform superiorly in modified 505 COD test when compared to weaker athletes. 3) Athletes who had more lower body force production asymmetry were more likely to perform asymmetrically during a COD test. However, the SD and the magnitude of asymmetry were not limiting factors for athletes’ COD performance.4) Male athletes demonstrated statistically significantly less COD total time, longer ground contact time (GCT), and better ability to apply forces and impulses while performing cutting. Based on the results, vertical forces and impulses during both the braking and propulsive phases of cutting ranged from 2.51 to 3.14 times larger than horizontal direction. In summary, stronger and more powerful soccer athletes were able to perform in a superior manner for both the COD tasks and straight-line sprinting. This may be due to the ability to produce high force and power during the critical time periods. Although force production asymmetry during related to the asymmetrical performance during COD tasks, the SD and the magnitude of asymmetry did not limit the COD performance. Finally, statistical differences existed between sexes in kinetic variables during cutting may be due to the different approaches to apply force in this task. Moreover, the ability to generate higher force and impulse in the vertical direction could affect COD performance.

Background: Plyometric training is a form of conditioning with increasing popularity that involves the performance of body weight jumping type exercises with the use of the stretch-shortening cycle muscle action. It is widely accepted that plyometric training has beneficial effects on many sports, including soccer. Objectives: To assess the effect of plyometric training on explosive actions of soccer performance (sprinting, jumping, agility, ball kicking) and indicated the kind, the frequency and targeted age groups on which the plyometrics should be executed. Methods: A search for all types of trials was performed on Pubmed, Web of Science and Sport Discus databases and the results were recorded according to PRISMA recommendations. 24 studies were included and judged for risk of bias and quality of evidence according to Cochrane guidelines and GRADE. Results: The studies were judges to have “low”, “high” and “unclear” risk of bias and were judged as “moderate”, “low” and very low quality of evidence. The finding of most of the studies show that plyometric training has beneficial effects and statistically significant improvements on the explosive actions (sprinting, jumping, agility and ball kicking) of young soccer players between 10 and 19 years old. Conclusions: The level of evidence of the review is moderate which means that further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. The current study suggests that plyometric training can be beneficial for young soccer players when is applied with gradual intensity, frequency of 2-3 times per week and along with regular soccer and strength training. Future research of higher quality of evidence studies and lower risk of bias should be performed in this field.

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.

Purpose: To investigate the effect of concurrent resistance and cycle training on the physiological and performance characteristics of well trained cyclists. Secondly, this study aimed to investigate the reliability of a new cycling time-trial test that incorporated repeated high-intensity sprint segments, both prior to and after a training intervention, with well trained cyclists.

The aim of this study was to investigate the acute effect of sprinting with a sledge upon running performances in sprint. Thirty four (23 men and 11 women) secondary school and university students with athletics experience (age 20.21 ? 3.22yr, mass 65.04 ? 10.89 kg, 171.21 height ? 8.29 cm) participated in the study. The subjects performed this protocol in a two non-consecutive days, doing a rest day or easy training between the days of protocol. This protocol consisted of each participant perform each day a group of sprints, one day 7x60m alternating with normal and sledge running and the other day 7x60m of normal running. The weight of the sledge was 10% of body mass of each participant. It was found that training with the sledge or without it have the same training effect, thus there is no acute effect of sprinting with a sledge upon running performances in sprint. It is concluded that when an athlete reports that felt running faster after using sledge it seems ir is only a subjective feeling.
O objetivo deste estudo foi investigar os efeitos agudos nas performances das corridas de velocidade usando um trenó como método de treino de resistência e depois correndo normal sem resistência. Trinta e quatro (23 homens e 11 mulheres) do ensino secundário e estudantes universitários com experiência na modalidade de atletismo (idade 20,21 ? 3.22 anos, massa 65,04 ? 10,89 kg, altura 171,21 ? 8,29 cm) participaram no estudo. Os indivíduos realizaram este protocolo em dois dias não consecutivos, fazendo um dia de descanso ou de treino mais leve entre os dias de protocolo. Este protocolo consistiu em cada participante realizar cada dia um grupo de sprints, um dia alternando 7x60m com corrida de velocidade normal e com o trenó e o outro dia 7x60m apenas com corrida velocidade normal. O peso do trenó foi de 10% da massa corporal de cada participante. Verificou-se que o treino com o trenó ou sem ele teria o mesmo efeito de treino, portanto, não há um efeito agudo de correr com um trenó e após fazer corrida de velocidade normal. Conclui-se que quando um atleta diz que se sentiu mais rápido a correr após o uso do trenó, pode ser apenas um sentimento subjetivo.

M.Phil. (Sport & Movement Studies)
Resistance training (RT) is an essential element of fitness for most sports. Most athletic activities involve faster and more powerful movements than those found in maximal strength exercises. Thus athletes could be exceptionally strong but lack explosive power. The aim of the study was to determine the possible effect of two different RT programmes on the sprinting performance of men aged 18–25. Body composition was assessed via anthropometrical measurements and lower extremity power was assessed via vertical jump and the Margaria Kalamen Power Test. Speed and acceleration will be assessed via a 40 meter, 60 meter, 80 meter and 100 meter sprint tests. Thirty athletes were randomly divided into three groups (two experimental groups n=10 each and a control group n=10). Two different RT programmes (“General”, G and “Specialised”, SP) were applied for eight weeks in the two experimental groups, while the control group (C) had no form of strength training. Both training programmes included two sessions per week, each lasting 60 minutes. Components that were tested included anthropometrical, body composition, lower extremity strength and 1RM measurements in regards to their 40m, 60m, 80m and 100m sprint time. Significant difference between SP, GP and C, at a P-value of 0.05, was determined by a dependant t-test. An independent t-test was used to determine significant difference between the three groups. The results showed that there was a significant improvement on body fat (BF) % in SP (-1.71 ± 0.21), GP (-0.19 ± 0.57) and muscle mass (MM) % in SP (1.88 ± 3.23). There was a significant difference in explosive power (MK) for the specialised group (p=0.013) and the 60m sprint for the specialised group (p=0.047). One repetition maximum (1RM) bench press (p=0.005 SP and GP), 1RM deadlift (p=0.005 SP), 1RM power clean (p=0.005 SP) and 1RM squat (p=0.005 GP) improved in the relevant groups as indicated. There was a significant difference between the groups completing a 60m sprint (p=0.022), 80m sprint (p=0.057), 100m sprint (p=0.025) and 1RM bench strength test (p=0.007) at post-test. Positive correlations were found between MM% on 60m (p=0.021), 80m (p=0.01) and 100m (p=0.019) sprinting times and MK and 40m (p=0.015) sprinting time.

Abstract Aim was to investigate the effects of heavy resisted and unresisted sprint training protocols and see its effects on sprint time, vertical and horizontal jumping and sprint mechanics. Youth male soccer players [n=27] participated in this study, they were all individually assessed for the horizontal force-velocity profile using two unresisted sprints and load-velocity profile using four progressively resisted sprints (25%, 50%, 75% and 100% body mass). For all sprints an isotonic braking device was used. They also performed vertical and horizontal jumps, counter-movement jump (CMJ) was used for the former and standing long jump (SLJ) for the latter. They were put in three groups (RST: resisted sprint training; UST: unresisted sprint training and TAU: control group – “training as usual”). Athletes performed a 4-week training intervention (5x20m resisted sprint group; 8x20m unresisted sprint group) and were tested 7 days after completing their final training session. Only RST improved all sprint times (T30, T20, T10, T5) substantially (-4.2% to -7.9% in split times) and provided trivial or small changes in sprint mechanics. The small changes were seen in sprint mechanical parameters of RFmax, Pmax and F0. UST only showed trivial effects in those parameters, while TAU showed a small decrease in both Pmax and Vmax. Regarding the jumps, RST and UST both showed a small increase in standing long jump and a trivial effect in counter-movement jump, while TAU decreased in both. Main conclusion is that resisted sprinting has proven to be a worthwhile method to improve acceleration and sprint performance and can be used by practitioners across a wide array of sports. It also improved jumping performance and sprint mechanical outputs, which point toward an improvement in better application of force in a horizontal direction.

An important issue for sports scientists, coaches and athletes is an understanding of the factors within a running stride that can enhance or limit maximal running speed. Previous research has identified many sprint-related parameters as potential kinetic limiters of maximal Center of Mass velocity (Chapman and Caldwell, 1983b; Weyand et al., 2001). Bilateral asymmetry is present for many of these parameters during running; however the degree to which such asymmetries change as running speed increases is unknown. It was hypothesized that asymmetries in key sprinting parameters would be larger at maximal speed than all other tested speeds. Kinematics and kinetics were collected from nine female competitive speed and power athletes (age = 21 ±3 years, mass = 60.58 ±7.48 kg, height = 1.64 ±0.07 m) who completed maximal and submaximal sprinting trials on a force-instrumented treadmill. A repeated-measures ANOVA was completed for each parameter to examine the asymmetry differences across speed. The only parameter for which asymmetry was statistically greater (p<0.05) during maximal speed than all other speeds was effective vertical stiffness, in which the level of asymmetry increased incrementally with speed (r2=0.97). Therefore the hypothesis that asymmetries would increase with speed for all key parameters is rejected. Bilateral asymmetries in effective vertical stiffness appeared to be related to asymmetries in both vertical and A/P propulsive impulse at maximal speed. Furthermore, asymmetries in effective vertical stiffness may force runners to resort to a less stable and less coordinated gait, limiting their ability to further increase stride frequency, and thus limiting maximal speed.

Thema works: An overview of the different forms of warm-up before athletic performance in sprinting. Student: Bc. Dominika Zapaľačová Supervisor: PhDr. Aleš Kaplan Ph.D Aims: The aim of this thesis is the study of scientific and professional literature and articles to obtain information on warming up before speed sports performance represented by quick sprinting. It is also to consider how subsequent various kinds of warm up exercises can affect the sports performance mentioned above. Furthermore, to use a case study based on selected research methodology to measure the speed of running locomotion after the selected type of warming up. Methodology: A method of literary research is used in the thesis, primarily using foreign literature but Czech literature too, obtained mainly from online databases and subject bibliographies. Also the case study method was used to measure the speed of running locomotion. Results: Conducting literary research has proved that speed sports performance might be greatly affected by the selected method of warming up. Most of the mentioned authors state the positive influence of dynamic stretching and they also recommend eliminating static stretching before speed sports performance. Measuring the speed of running locomotion has proved that the probands did not show any...

ACTN3 has been labelled as the ‘gene for speed’ due to the increased frequency of the R allele encoding the α-actinin-3 protein in elite sprint athletes compared to the general population. The results of the first study of this thesis demonstrate that elite athletes who express α-actinin-3 (ACTN3 RR genotype) have faster sprint times compared to those who do not express α-actinin-3 (ACTN3 XX genotype). Further analysis indicates that the ACTN3 genotype accounts for 0.92% in sprint speed amongst elite 200-m athletes. In study two, the same quantitative genetic epidemiological design applied to elite endurance athletes, showed no evidence that a trade-off existed. The endurance athletes with the ACTN3 XX genotype were no faster than those who express the α-actinin-3 protein. These results added to literature that it is unlikely the ACTN3 XX genotype to offer an advantage for endurance performance. While ACTN3 genotype does not appear to influence endurance performance in athletes, studies in mice that completely lack the α-actinin-3 protein suggest the ACTN3 genotype influences the adaptive response to endurance exercise. Based on these findings, the aim of study 3 was to investigate if ACTN3 genotype influences exercise-induced changes in the content of genes and proteins associated with mitochondrial biogenesis. At baseline, there was a compensatory greater α-actinin-2 protein content in ACTN3 XX vs ACTN3 RR participants (p=0.018) but there were no differences in the endurance-related phenotypes measured. There was a main effect of genotype (p=0.006), without a significant interaction effect, for RCAN1-4 or significant exercise-induced expression of genes associated with mitochondrial biogenesis. Together, these results suggest that ACTN3 genotype has a small but significant influence on sprint speed amongst elite sprint athletes. However, loss of α-actinin-3 protein is not associated with higher values for endurance-related phenotypes, endurance performance, or a greater adaptive response to a single session of high-intensity endurance exercise.

This thesis investigated acceleration in soccer and the ability to improve acceleration capacity using supplementation and a training intervention both separately and in combination. Study one determined the validity and reliability of 5 and 10 Hz global positioning systems (GPS) for measuring instantaneous speed during the acceleration, deceleration and constant speed phase of straight-line running. The criterion measure used to assess GPS validity was instantaneous speed recorded using a tripod-mounted laser. Ten Hz GPS devices were 2-3 times more accurate than 5 Hz when compared to a criterion value for instantaneous speed during tasks completed at a range of speeds (coefficient of variation; 3.1 - 11.3%). Similarly, 10 Hz GPS were up to 6-fold more reliable for measuring instantaneous speed than 5 Hz units (coefficient of variation; 1.9 - 6%). Newer GPS may provide an acceptable tool for the measurement of constant speed, acceleration and deceleration during straight-line running and have sufficient sensitivity for detecting changes in performance in team sport. However, researchers must account for the inherent match-to-match variation reported using these devices.

The overall aim of this research was to examine the factors that influence the coach-biomechanist relationship in the elite sprinting context and gain an understanding of the factors that impede and enhance performance environments and relationships. It is thought that the transfer of sport science research into coaching practice is not as efficient as it should be, as it has been established that coaches are not using sport science as a source of knowledge. Subsequently, this insufficient transfer of knowledge could be limiting potential improvements in athlete performance. Technique analysis is a common area of expertise for both sprint coaches and biomechanists in high-performance sport and was therefore the ideal context to explore the coach-biomechanist relationship in detail. The first phase of research examined the coach and biomechanists’ understandings of optimal sprint running technique and determined the relationships between the experiential knowledge of the two groups. Findings showed elements that are crucial to optimal sprinting technique, such as the position of the contact foot and extension of the leg during stance. Differences in knowledge between the two groups were complimentary. For example, the biomechanists’ focus on the transition from swing into stance phases and the coaches’ interest in upper body movement. Moreover, the communication of these knowledge differences was potentially problematic. The second phase of this research determined if the knowledge differences found in the first phase influenced the visual search patterns of coaches and biomechanists. This difference was not observed, with visual search behaviour not reflecting the differences in knowledge seen in phase one. The third phase aimed to establish the context in which coaches and biomechanists interact to improve performance. This phase supported previous phases’ results in that communication styles and knowledge differences were impeding factors and added lack of role clarity to this list. The fourth and final phase investigated the interactions and exchange of information that occurs during the technique assessment process. Results showed that the process is a coach-led partnership where rapport building, and equal sharing of knowledge are emphasised. In summary, this research contributes to the understanding of the coach-sport science relationship by providing practical evidence for numerous concepts in a novel and more specialized population. It increases our understanding of coach technical knowledge and visual perceptual behaviour as well as uniquely incorporating the sport biomechanists’ knowledge and perspective into these investigations. The multi-layered approach used allowed the knowledge, behaviours and interactions that comprise qualitative analysis of technique to be investigated. This has greatly improved our understanding of the coach- biomechanist relationship and the factors that impede and enhance it.