The purpose of this study was to quantify the EMG activity of selected lower limb muscles during cycling, and to define the relationship between pedal shaft width and muscular involvement. This study has particular significance to the female cyclist who by virtue of pelvic width may have a less efficient pedalling force, or an imbalance of applied muscular force. Variables analyzed were hip, knee, ankle range of motion (ROM), biceps femoris(BF), vastus lateralis(VL), rectus femoris(RF), and vastus medialis(VMO) muscle activity. Significant differences among three different pedal shaft widths were determined through use of repeated measures oneway ANOVA, Newman-Keuls post hoc test. The hip ROM, biceps femoris, and vastus medialis EKG activity results of the present study appeared to indicate that different pedal shaft widths had an effect on changes in the ROM and EMG activity. This study indicated that the hip ROM values increased with an increase in the pedal shaft width. In contary, an increase in pedal shaft width significantly decreased the muscle activity in the vastus medialis while two inch pedal shaft width significantly decreased the muscle activity in the biceps femoris. / School of Physical Education

No description available.

Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Homoeopathy , Durban University of Technology, 2011. / The treatment with homoeopathic remedies, namely Phosphoricum acidum 200CH has proved to be effective in many clinical situations; however confirmation of its use within the sporting industry is limited. This study aimed to test Phosphoricum acidum 200CH efficacy in treating highly trained cyclists. This study was a superiority trial, in which the homoeopathic intervention was hypothesized to be superior to the placebo control group, in a statistically significant way (p < 0.05). Aim This study aimed to test the use of Phosphoricum acidum 200CH in treating the adverse physiological and psychological symptoms induced by exercise on cyclists. The aim for treating these adverse symptoms, induced by exercise, is to enhance performance and recovery of cyclists. Performance and recovery were tracked by assessing blood lactate concentration, oxygen consumption rate, heart rate, peak power output and emotional status. Methodology The study was a randomized controlled clinical trial, parallel group design. Participants were selected using convenience sampling of male road and mountain bike cyclists in the Western Cape. This study followed an explanatory Randomized Controlled Trial test, where the efficacy of the homoeopathic remedy (Phosphoricum acidum 200CH) was under investigation. The participants were selected with great care and testing was completed under highly controlled conditions. Thirty competitive male cyclists volunteered for this study. All participants were required to complete two cycling power to exhaustion interval tests, consisting of a ten minute warm-up at 100 Watts, followed by a five minute constant load at 150 Watts. The purpose of the constant load was to test cycling economy (CE). Thereafter the workload was increased to 200 W for 30 seconds and then the workload was increased by 20 Watts every 30 seconds. The test continued until the participant could no longer maintain the set repetitions per minute for that workload. The peak power output attained iv was recorded. The first test served as a baseline, after which a single dose of Phosphoricum acidum 200CH or identical placebo was administered, a 30 minute recovery period allowed for the remedy to take effect. The test interval was then repeated, the second test results were then compared to the first baseline test to determine the effect of treatment. The study took many different aspects of the remedies action on the cyclists into account, including mental and physiological effects. Breath-by-breath gases were continuously recorded. Expired gases, volumes and air flow were sampled through a flow meter and gas sampling line and heart rate was measured through telemetry (Polar®, Polar Electro, Oy, Finland) and analyzed by a cardio-pulmonary metabolic system (Quark CPET ® Cosmed, Rome, Italy, 2009). Data recorded was filtered for values outside the normal ranges and averaged for every five seconds. Oxygen consumption (vO2 mL.min-1) and heart rate (bpm) at different stages of each test interval were recorded. More specifically oxygen consumption and heart rates were averaged over the 5 minute section following the warm-up to determine cycling economy, directly after exhaustion for one minute and two minutes following exhaustion for another one minute period. Maximum attained heart rate was recorded for each interval test. Maximum oxygen consumption (vO2Max Absolute) was calculated as the mean of the highest three values attained, this mean was then divided by the participants body mass to determine maximum aerobic capacity (vO2Max Relative). Blood lactate levels were tested before, 15 minutes into and directly after each interval, to assess resting lactate status, cycling economy and to determine maximum lactate accumulation. Psychological testing included mood analysis, using a Stellenbosch mood scale (STEMS) questionnaire and further symptoms were analyzed using a Numerical rating scale (NRS) with symptomatic questions. Results From the results, it was clearly apparent that the control group proved to be of a higher calibre when comparing performance variables of the two groups namely:  Higher peak power output  Higher vO2Max  Lower economy lactate v  Lower resting lactate Despite the treatment group being the weaker of the two groups, they showed improvement in performance after administration of the remedy. This improvement was manifest through physiological alteration in the second test. More exclusively is the acceptance of the hypothesis concerning heart rate and oxygen consumption, whereby results showed that the administration of Phosphoricum acidum 200CH decreased heart rate and submaximal oxygen consumption rates during performance and recovery. There was no observable psychological effect during this study. The results suggest that Phosphoricum acidum 200CH primary demonstrated physiological effects on the cyclists. The researcher believes that this is due to insufficient time given for psychological alterations. Conclusion The Phosphoricum acidum 200CH has proven to be effective in enhancing cycling economy, reducing maximum heart rate and enhancing recovery to a large degree for the first minute following exhaustion. These positive effects are of great importance as the treatment group was the weaker of the two groups. Resulting in the possibility of even larger results being observable in repeated studies where both groups have similar performance abilities.

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: A 5 km cycling time trial (TT) demands high, sustained muscle power output and substantial oxidative and glycolytic energy delivery. The aims of this study were to firstly use the novel approach of using Peak Sustained Power Output (PSPO) as a predictor of cycling performance for variable fixed-workload testing and 5 km time trialing and whether oral creatine supplementation would affect 5 km time trial performance and metabolism. The effect of oral creatine supplementation with 20 g/day for 7 days on 5 km time trial performance and metabolism after a random-variable workload protocol (stochastic test) was investigated in a single-blind placebo controlled study. Thirteen trained male cyclists volunteered for the study that was approved by the University of Stellenbosch Research Ethics Committee. We hypothesized that Cr supplementation would affect time trial performance as well as the appearance of breakdown products of adenine nucleotides in the plasma. Baseline: the subjects' peak power output was measured and they underwent a baseline stochastic test followed immediately by a 5 km time trial (STI) and on a different day, a single 5 km time trial test (Tl) was undertaken. Study 1: In the following week the subjects repeated the stochastic test with 5 km time trial (ST2) and on a different day a 5 km time trial (T2). During T2 blood samples were taken at regular intervals as well as during recovery. A muscle biopsy was taken after T2 in the recovered state. The major performance predictors were the 5-km time trials (TTl and TT2) with a coefficient of variation between the thirteen trained male cyclists of 0.6%. The 5 km time trials in the fatigued state (STI and ST2) had a coefficient of variation of 0.7%. Results: There was a significant difference between 5 km TT performed fresh and 5km TT performed fatigued (P=0.0001). The decrement in time ranged between 1.0 sec to 38.0 sec. The relationship between two different high intensity endurance performance tests: PSPO and 5 km TT (TT mean) had a correlation ofr=-0.79 P<O.OI. The correlation between PSPO and the 5 km TT performed in the fatigued condition (ST mean) was r= -0.60 P<0.05. There was also a relationship between age and PSPO (F 0.73; P<0.05). Age showed a good negative relationship with TT mean (F- 0.71; P<0.05). Mass and PSPO were also correlated (FO.85; P<O.OI). Plasma lactate concentrations were significantly different from rest at all other time points P<O.OOOIup to 20 minutes post-exercise. Hypoxanthine (P<O.OOOI)and urate (P=O.05) concentrations were also significantly different from rest at all other time points. There was a significant change in plasma hypoxanthine concentrations over time (P<0.0001). There was a significant correlation between plasma lactate concentration at time 0 in recovery and % Myosin Heavy Chain (MHC) I (FO.59, P<0.05) and % MHC na (F -0.61, P<0.05). Area under the curve for hypoxanthine showed significant relationships of F -0.53 (P=O.05) and F 0.56 (P<0.05) respectively for %MHC I and %MHC ITa. Study 2 - Supplementation: following T2 the subjects received Cr or placebo powder containing sachets to be ingested 4 times daily for the next week with carbohydrate also provided. Post-supplementation testing: the subjects returned and conducted another variable fixedworkload test with 5 km time trial (ST3) as well as a single 5 km time trial (T3). They once again underwent the same blood sampling routine and had another muscle biopsy in the rested state. The average of ST1 and ST2 was used as the major measure for performance under fatigued conditions and TTmean. Results: there was a significant difference between 5 km TT performed fresh and 5 km TT performed fatigued (P=0.0001). Plasma lactate, hypoxanthine and urate samples were taken at the postloading 5 km time trial (TT3). The levels of these plasma metabolites were compared to the concentrations of those sampled at TT2 and between the creatine and placebo groups. The plasma hypoxanthine levels were significantly different from rest for both the creatine and placebo groups (P<0.0001). Plasma urate had significant change in concentrations over the time points (P<0.005). Another significant difference was found between the creatine and placebo groups for the pre-and post tests conducted (P<0.005). The creatine group showed a non-significant increase (7%) in mean total intramuscular creatine concentration. No significant differences were found in the mean values for total nucleotide concentration pre- and post loading in the creatine and placebo groups. Conclusions: The 5 km performance test resulted in high values for plasma lactate, hypoxanthine and urate, an indication of fatigue induced by this performance test. Oral creatine supplementation did not improve performance significantly in the variable fixedworkload protocol 5 km time trials or the individual 5-km time trials and had an effect on adenine nucleotide metabolism in both the variable fixed-workload protocol 5-km time trial and individual 5 km time trial performance tests. / AFRIKAANSE OPSOMMING: Die 5 km fietsry tyd toets (TT) verg hoëvolgehoue, spierkrag en wesenlike oksidatiewe en glikolitiese energie verskaffing. Die doelwitte van hierdie tesis was eerstens om 'n nuwe fietsergometer toets te ontwerp vir die voorspelling van kompetisie prestasie. Die toets was 'n veranderlike, voorafvasgestelde werkladingstoets (VVWT). Dit is vergelyk met 'n maksimale volgehoue kraguitsetingstoets (MVKT) en 'n 5 km TT. Daarna is bepaal ofkreatien supplementasie 'n effek sou hê op enige van hierdie oefeningstoetse of metabolisme tydens die 5 km TT. Die supplementasie eksperiment was 'n enkelblinde, plasebo-gekontroleerde studie ontwerp. Dertien manlike fietsryers het vrywilliglik deelgeneem. Resultate: Daar was 'n statisties betekenisvolle verskil tussen die 5 km TT wat vars onderneem is en die wat direk na die VVWT onderneem is (P=O.OOOl). Daar was ook 'n betekenisvolle korrelasie tussen die twee verskillende hoë intensiteit korttydsvak oefeningstoetse (r=-0.79 P<O.Ol vir TT en MVKT). Plasma laktaat konsentrasies was betekenisvol verhoog met vergelyking van die monsters geneem tydens rus en all ander onteledings tydspunte (P<0.0001) tot en met 20 minute na oefening. Hypoxantien (P<O.OOOl) en uraat (P=0.05) konsentrasies was ook betekenisvol verskillend van rus by alle ander tysdpunte. Daar was 'n betekenisvolle korrelasie tussen plasma laktaat direk na oefening en die % Myosien Swaarketting (MIlC) I (r=0.59, P<0.05) en % MHC ITa (r= - 0.61, P<0.05). Studie 2 - Na supplementasie was daar geen verskil in oefeningsprestasie nie maar wel in plasma metaboliet waardes van nie. Gevolgtrekkings: Die 5 km TT het baie hoë waardes vir plasma laktaat tot gevolg gehad, asook hypoxantien en uraat, 'n indikasie van die hoë mate van vermoeienis deur hierdie oefeningtoets berwerkstellig. Kreatine supplementasie kon nie oefeningsprestasie verbeter nie.

The purpose of this study was to examine the acute effects of cycling exercise at different intensities and rest intervals on strength performance. Ten males, engaged in concurrent training for at least one month prior to testing, comprised the subject group for this study. Results show only leg press torque and leg press work to be decreased after cardiorespiratory exercise of moderate intensity. Leg extension average power, chest press torque, chest press power, and chest press work after cycling were not decreased from pre-exercise values. No significant effects were found for exercise intensity, testing times, or intensity by testing times. These results indicate that lower body strength is decreased by cycling and that one hour is not sufficient to restore leg strength.

Certain measures of aerobic power have been shown to have a high relationship with endurance performance. Critical power (CP) has also been shown to be well correlated to endurance performance, but few studies have evaluated its use in a competitive scenario. In this study, cardiorespiratory-metabolic measures were evaluated in 13 highly trained cyclists to determine their relationship to performance in a 17 km time trial. Critical power, determined from the nonlinear power-time model, was also evaluated to determine its relationship to performance in a 17 km time trial. Results indicate that the traditional indicators of V02max and ventilatory anaerobic threshold were well correlated to TT performance (r=-0.86, r=-0.79, respectively). The principal finding from this study was that performance in a bicycle time trial is related to CP at least as well as to cardiorespirator-ymetabolic measures. In fact, the results fromthis study suggest that the relationship between performance and CP is stronger (r=-0.89). Use of the critical power concept is attractive because testing requires only a cycle ergometer and a stopwatch to estimate a parameter of aerobic fitness.

Graduation date: 1992

The purpose of this study was to compare the concentration of and the time to peak blood lactate following three 90-s cycle ergometer tests--intermittent all-out (Int-A), continuous all-out (Cont-A), and continuous constant (Cont-C), and to compare group peak lactate to blood lactate at individual peak time. Eight fingertip blood samples were drawn between 1 and 12min post-exercise. Subjects were university hockey players (n = 19) and physical education students (n = 19). The two all-out tests had a higher peak concentration than the Cont-C test (P $<$ 0.05). The Int-A test had an earlier peak than the two continuous tests (P $<$ 0.05) but this difference vanished if peak time was measured from the onset of the tests. A number of sampling times had lactate concentrations similar to the individual peak concentration (P $<$ 0.05): (1) 1, 2, 3, and 4min for Int-A; (2) 2, 3, 4, 5, and 6min for Cont-A; (3) 2 and 4min for Cont-C.

Exercise-induced hypoxemia is a common observation in endurance-trained athletes. The present study examined the kinetics of oxyhemoglobin saturation during upright (UP) maximal cycling exercise in 84 healthy, untrained subjects between 8 and 26 years old. The prevalence of oxyhemoglobin desaturation (DS: SaO$ sb2 $ 0.05). A subgroup of children (n = 6) repeated the maximal exercise protocol in the supine (SU) position. In NDS values of SaO$ sb2$ were not affected by posture (UP: 95.3 $ pm$ 2.3 vs SU: 94.1 $ pm$ 0.9) for similar VO$ sb{ rm 2max}$ (UP: 3.7 $ pm$ 0.36 vs SU: 3.43 $ pm$ 0.36) (p $>$ 0.05). These observations suggest that exercise-induced DS is independent of age or training status. Differences due to posture may be related to variations in ventilatory and/or pulmonary perfusion parameters.

The purpose was to examine the effect of body mass and body composition on the mean power output in the 30 second Wingate cycling test at five resistance settings. Forty females (X = 22 years), were divided into four groups based on body mass and the sum of five skinfolds. The Wingate test was performed at the resistance settings of 0.075, 0.080, 0.085, 0.090, and 0.095 kp/kg body weight. A 3-way ANOVA (mass, skinfolds, resistance settings) indicated that: (1) mean power (W/kg) was similar for low and high mass groups; (2) the low sum of skinfolds group had a significantly higher (p $<$ 0.02) mean power output than the high sum of skinfolds group; and (3) at resistance settings of 0.080, 0.085, 0.090, and 0.095 (kp/kg) the low sum of skinfolds group had a higher (p $<$ 0.05) mean power score than the high sum of skinfolds group at equivalent resistance settings.