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Item Comparing the Effects of Collagen Hydrolysate and Dairy Protein on Recovery from Eccentric Exercise: A Double Blind, Placebo-Controlled Study.(MDPI (Basel, Switzerland), 2024-12-20) Barclay R; Coad J; Schraders K; Barnes MJ; Driss TBackground: Consuming collagen hydrolysate (CH) may improve symptoms of exercise-induced muscle damage (EIMD); however, its acute effects have not been compared to dairy protein (DP), the most commonly consumed form of protein supplement. Therefore, this study compared the effects of CH and DP on recovery from EIMD. Methods: Thirty-three males consumed either CH (n = 11) or DP (n = 11), containing 25 g of protein, or an isoenergetic placebo (n = 11) immediately post-exercise and once daily for three days. Indices of EIMD were measured before and 30 min and 24, 48, and 72 h after 30 min of downhill running on a −15% slope at 80% of VO2max speed. Results: Downhill running induced significant EIMD, with time effects (all p < 0.001) for the delayed onset of muscle soreness (visual analogue scale), countermovement jump height, isometric midthigh pull force, maximal voluntary isometric contraction force, running economy, and biomarkers of muscle damage (creatine kinase) and inflammation (interleukin-6, high-sensitivity C-reactive protein). However, no group or interaction effects (all p > 0.05) were observed for any of the outcome measures. Conclusions: These findings suggest that the post-exercise consumption of CH or DP does not improve indices of EIMD during the acute recovery period in recreationally active males.Item Risk Factors for Horse Fatality in Thoroughbred Jumps Racing in New Zealand.(Elsevier B.V., 2023-10-01) Gibson MJ; Legg KA; Gee EK; Rogers CWThe aim of this study was to examine the race-, horse- and jockey-level risk factors for race day fatality in New Zealand Thoroughbred jumps racing using retrospective race day data from the 2011/12 to 2021/22 seasons (n = 8,970 starts). There were 51 race day fatalities resulting in an incidence rate of 5.7 per 1,000 starts (95% C.I. 4.3-7.5). The majority of fatalities were the result of fractures (44/51, 4.9 per 1,000 starts, 95% C.I. 3.7-6.6). Steeplechase and hurdle races had the same incidence of fatal fractures of 4.9 per 1,000 starts (95% C.I. 3.7-6.6, P > .05). Most (70.5%) of the fatal fractures were due to a horse falling during the race. In steeplechase races, horses running in races over 4,201 m were 5.0 times (95% C.I. 1.2-33.0) more likely to sustain a fatal fracture than horses in racing over shorter distances. In hurdle races, horses racing during spring were 2.2 times (95% C.I. 1.0-4.8) more likely to sustain a fatal fracture compared to winter. Due to the low number of suspected cardiac failures and fatal soft tissue injuries, risk factors for these fatalities could not be identified. These data provide a baseline to enable evidence-based regulatory changes and prospectively monitor the effectiveness of changes made.Item Observed versus expected match-running outputs of international female rugby sevens players : a thesis submitted to Massey University, Albany, New Zealand in fulfilment of the requirements for the degree of Master of Sport and Exercise(Massey University, 2018) Yallop, KirstyWomen’s rugby sevens is a new and emerging sport with limited knowledge, specifically on international female match-running outputs. It is a rare opportunity to conduct research on elite athletes, and even more so for an emerging women’s sport. The overall aim of this thesis is to establish and compare observed international female rugby sevens players’ match-running outputs versus theoretical expected match-running outputs (elite male players and an established sport, football). Another unknown aspect of the women’s rugby sevens game is how fatigue affects performance. The thesis also determines differences in match-running outputs of international female rugby sevens players from half-to-half, game-to-game and tournament-to-tournament. Global Positioning System (GPS) units worn on the players’ backs were used to collect data from 18 female rugby sevens players across 15 matches and 19 female football players across four matches. Reasons for the gaps found in match-running outputs and aspects that could be improved for optimal elite performance in female rugby sevens were explored. The match-running output measures included low-to-moderate speed running (LMSR <16.5 km), high speed running (HSR >16.6 km), sprints (>21 km) and total distance (TD). These speed thresholds represent previously used zones in rugby sevens match analysis, as well as recommended zones for female sport settings (VX View software). When compared with the expected match-running output measures, male and female rugby sevens players exhibited a large sex performance gap with male players recording more metres across all four measures, LMSR 64.8% (p<0.01), HSR 95.9% (p<0.01), TD 69.3% (p<0.01) and sprints 100% (p<0.01). Female football players and male football players demonstrated an unexpected sex performance gap in HSR of 152.3% (p<0.01), with male players performing more HSR metres. There was a smaller gap in TD 25.3% (p<0.01) and sprints 52.9% (p<0.01) and within the established performance gap for LMSR 2.3% (p = 0.28) between male and female footballers, again with male players recording more metres. There were no significant decreases in match-running outputs for female rugby sevens players from 1st half to 2nd half. However, female football players showed a significant decrease in match-running output in LMSR (p<0.01), TD (p<0.01) and sprints (p<0.01) from 1st half to 2nd half. There were significant differences in match-running output in LMSR (p<0.01) for female rugby sevens players, specifically with an increase between tournaments 2 and 3 (p<0.05) and tournaments 1 and 3 (p<0.05). There were also significant differences in the number of sprints performed (p<0.01), with an increase between tournaments 1 and 2 (p<0.05), and a decrease between tournaments 2 and 3 (p<0.05), and a decrease between games 7 and 11. There were no significant differences in match-running outputs for female football players from game to game. Overall, the findings from this thesis contribute to the limited knowledge on women’s rugby sevens, specifically observing international female match-running outputs. The findings suggest that international female rugby sevens players have significant room to improve overall match-running outputs, aligning more closely with the expected sex performance gap (5-12%) and the established elite sport of football.Item Effect of foot orthoses on GRF in running gait : a thesis presented in partial fulfillment of the requirements for the degree of Masters of Philosophy, Massey University(Massey University, 2004) Sloane, JohnFor many years foot orthoses have been used to treat injuries of the feet, lower limb and back. Much of the evidence for their use has been anecdotal and measurement of kinematic or kinetic effects has been inconclusive. A single subject was selected for this case study to test the effect of orthoses on ground reaction forces during running. The subject was a competitive multi-sports athlete, and a heel strike runner (characterized as a runner who's heel is the first part of the foot to contact the ground). The experiment was conducted in a hall on a 40m curved running track with a force plate on one side. Timing lights were placed 5m from each end of the plate to measure speed and a video camera recorded the foot strike on the plate. The subject was asked to run at constant speed while wearing shoes and shoes with foot orthoses, at two self-selected speeds. Data from left and right foot was combined for analysis. The results showed a significant decrease in the magnitude of the vertical impact peak and the maximum vertical peak while the time to vertical impact peak was increased when wearing foot orthoses. Significant reductions were also seen in the peak posterior shear with both the time to peak and magnitude of the peak being changed by wearing foot orthoses. The mediolateral force was characterized by a medial impact followed by larger lateral impulse. It is the lateral force in the absorption phase of stance that is responsible for pronation, however no changes were seen in the mediolateral ground reaction force with the use of foot orthoses. This indicates that there is no acute effect in the shear forces, that act at approximately right angles to the subtalar joint axis. If orthoses have an acute effect on the lower limb it is likely to be complex and highly patient specific.Item Superior running economy in obese compared to normal-weight males at metabolically comparable work rates : a thesis presented in fulfilment of the requirements for the degree of Master of Science in Sport and Exercise at Massey University, Wellington, New Zealand(Massey University, 2014) Stewart, James AndrewIntroduction: During weight bearing physical activities such as walking or running, obese individuals generally expend more total energy than their lighter counterparts. Running economy (RE) is an important physiological measure in the sports performance field and is defined as the aerobic capacity per kilogram of body mass required to sustain a given submaximal running speed. RE can also help us assess how other individuals would cope with a certain intensity of activity. Superior RE is seen in elite endurance athletes by using less oxygen per kilogram of body mass at a given speed. Fit/trained individuals display a superior RE compared to unfit/untrained individuals. Normal weight subjects have previously been shown to display a superior RE than obese individuals; furthermore, low cardiorespiratory fitness (CRF) is an important reversible cardiovascular disease risk factor, while obesity is a major risk factor for non-communicable diseases. Although RE has previously been assessed at absolute exercise intensities to compare between groups, (i.e. obese vs. normal weight) individuals exercise at a metabolic rate that is scaled to body size and relativised for fitness level. Purpose: To assess RE and the physiological responses of normal weight-unfit (NWU) and obese-fit (OBF) adult males during treadmill running when relative exercise intensities are selected. It was hypothesised that the RE of OBF would be superior to that observed for NWU. Methods: Healthy NWU (n = 12, 38.2 ± 9.1 yrs, 77.3 ± 6.4 kg, 24.0 ± 1.3 kg·m-2) and OBF (n = 11, 38.5 ± 6.0 yrs, 103.8 ± 8.0 kg, 33.3 ± 2.2 kg·m-2) volunteered for the study. Following risk stratification assessment for coronary artery disease and a treadmill walking ECG, participants completed two laboratory based tests. Participants firstly completed a submaximal incremental graded exercise test up to 85% HRmax (age predicted) on a treadmill. Individual linear regression analysis was then used to predict maximal aerobic power ( O2max) for each participant. Following a minimum 72 hour recovery period, participants then completed a further test at two independent intensities: ventilatory threshold (VT) and 40% delta (Δ) as identified from the GXT. Each independent intensity was sustained for 6 minutes duration, separated by 5 minutes of standing recovery. Physiological markers (Heart Rate [HR], oxygen uptake [ O2], minute ventilation [ E] and respiratory exchange ratio [RER]) were continuously monitored, while the ratings of perceived exertion (RPE) and stride rate were recorded at 3 minutes and at the completion of each exercise stage. Results: OBF elicited a significantly higher running speed at VT (8.5 vs. 7.6 km·h-1; P < 0.01) and at 40% Δ (10.1 vs. 8.8 km·h-1; P < 0.01) compared to NWU V! V! V! Abstract Superior Running Economy in Obese Compared to Normal-Weight Males respectively. OBF displayed a significantly superior (lower) RE (210.7 ± 8.0 vs. 253.2 ± 7.6 mL·kg-1·km-1; P = 0.001), than in NWU respectively. No significant differences were observed between VT and 40% Δ (P > 0.05). When RE was assessed relative to fat free mass (FFM), no differences were found between OBF and NWU (P > 0.05). However, a significant difference in RE was observed at VT compared to 40% Δ (322.3 ± 7.3 & 368.8 ± 8.9 mL·FFM-1·km-1, respectively; P < 0.001). Conclusion: Despite running at a faster speed, fit and obese individuals displayed a superior running economy compared to normal weight unfit individuals during treadmill running at relative moderate and heavy exercise intensities when expressed as mL·kg-1·km-1. When expressed relative to fat free mass (mL·FFM-1·km-1) no differences in RE were observed between groups. Fitness and training status rather than weight status may be more of an important moderating factor when examining differences in RE between individuals. The proposed mechanisms for the results remain unclear. It is acknowledges that greater subject numbers including obese unfit and normal weight fit would have allowed for a more valid interpretation of the present findings. From a public health perspective these results indicate that increasing physical activity and fitness level should be a priority for adults engaging in an exercise programme more so than weight loss, as superior economy could reduce the relative level of physical exertion during everyday tasks.Item A mathematical and computer simulation model of the running athlete : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mathematics at Massey University(Massey University, 1984) Morton, Richard HughThis thesis describes the construction, computerisation and simulation of a mathematical model of the running athlete. The model is in part biomechanical and in part biochemical, in part theoretical and in part empirical. A three variable (force, velocity and distance) Newtonian biomechanical model of Keller (1973, 1974) is examined, and extended to include a fourth variable, power developed. This model segment is feed-forward linked by equating mechanical power developed to bioenargetic power supplied. A proposed three component bioenergetic model of Margaria (1976) was examined in detail (Morton 1984), but found to be unsuitable. Thus an empirical three component model segment was developed. Bioenergetic power is supplied by three variables, oxygen uptake, and glycolytic and alactic body energy store depletions. The glycolytic process is of particular interest, since the accumulation of lactic acid in the working muscle can induce fatigue. A two compartment, working muscle and blood volume, physiological model segment originally developed by Freund and Zouloumian (1981a, b) for post exercise is examined for use during exercise. This segment takes as input the lactate produced by the glycolytic energy process and circulates it between compartments, or removes it by biochemical breakdown. Lactate concentrations in the two compartments are the modelled variables in this segment. Finally a negative feedback link in the whole model is provided by a fatigue equation, where the maximum muscular force exertable is constrained inversely by the lactate concentration increase in the working muscles. The athlete of course can by choice operate at a force below the constraining level, in which case the feedback link does not operate. Sooner or later however, except for the lower workloads, muscular lactate will build up to such a level as to invoke the feed-back. Parameters of the whole model include initial body energy stores, maximal muscular strength, resistance to motion, diffusion constants for lactate circulation, bioenergetic parameters of the oxidative, glycolytic and alactic energy processes, biomechanical energy equivalents, body mass, fatigue coefficients, etc, twenty four in number. These parameters bind the relationships between the nine variables of the whole model, expressed as nine simultaneous differential equations with respect to time. Parameter values were in some cases obtained by estimation from data on exercising subjects, specially collected for that purpose. In other cases values determined experimentally by other researchers and published in the literature were utilised. Simulation was performed using numerical integration methods provided by a computer programme from the NAG library of routines (NAG, 1983). Simulated results on all nine variables are realistic, conforming well to those observed in the laboratory on exercising subjects. There remains scope however for future refinements, in the main improving the theoretical content of the whole model and in the process extending it to include the recovery period after exercise.