GPS analysis of a team competing at a national Under 18 field hockey tournament

The purpose of this study was to utilise global-positioning system (GPS) technology to quantify the running demands of national Under 18 field hockey players competing in a regional field hockey tournament. Ten male players (mean ± SD; age 17.2 ± 0.4 years; stature 178.1 ± 5.2 cm; body mass 78.8 ± 8.8 kg) wore GPS units while competing in six matches over seven days at the 2018 New Zealand national under 18 field hockey tournament. GPS enabled the measurement of total distance (TD), low-speed activity (LSA; 0 -14.9 km/hr), and high-speed running (HSR; ≥ 15 km/hr) distances. Differences in running demands (TD, LSA, HSR) between positions were assessed using effect size and percent difference ± 90% confidence intervals. Midfielders covered the most TD and LSA per game and strikers the most HSR during the 6 matches. There were “very large” differences between strikers and midfielders for TD and LSA, strikers and defenders for LSA and HSR, and defenders and midfielders for LSA. These results suggest that these playing positions are sufficiently different to warrant specialised position-specific conditioning training leading into a field hockey tournament

The effects of morning preconditioning protocols on testosterone, cortisol and afternoon sprint cycling performance [conference presentation]

Opportunities exist for athletes to undertake morning exercise protocols in an attempt to potentate afternoon performance. Four sub elite track sprint cyclists completed a morning cycling (Cyc) or weights-based protocol (WP) prior to an afternoon cycling time trial (500m) in a repeated measures, counterbalance crossover design. Measured variables included heart rate, blood lactate, cycling peak power, salivary testosterone (T) and cortisol levels along with time trial performance. Standardised differences in means via magnitude-based inferences were calculated using paired samples T-tests in SPSS version 24 with statistical significance set at p < 0.05. The WP produced significantly faster times in the final 250m in comparison to CycP. The anticipated circadian decline of T was observed after the CycP but was however mitigated following the WP. While slight decreases in 500m times were experienced during the WP, they were not significant and were considered within the normal variations experienced between performances by elite athletes. The effect of the WP on the circadian rhythm of T could be linked to a greater recruitment of muscle fibres. Results suggest a morning resistance protocol can positively affect testosterone levels for afternoon performance. Possible gender and individual responses from conducting a W over Cyc protocol were observed and require further investigation

Arm-cranking exercise assisted by Functional Electrical Stimulation in C6 tetraplegia: a pilot study

Tetraplegic volunteers undertook progressive exercise training, using novel systems for arm-cranking exercise assisted by Functional Electrical Stimulation (FES). The main aim was to determine potential training effects of FES-assisted arm-crank ergometry (FES-ACE) on upper limb strength and cardiopulmonary {fitness} in tetraplegia. Surface FES was applied to the biceps and triceps during exercise on an instrumented ergometer. Two tetraplegic volunteers with C6 Spinal Cord Injury (SCI) went through muscle strengthening, baseline exercise testing and three months of progressive FES-ACE training. Repeat exercise tests were carried out every four weeks during training, and post-training, to monitor upper-limb strength and cardiopulmonary fitness. At each test point, an incremental test was carried out to determine peak work rate, peak oxygen uptake, gas exchange threshold and oxygen uptake-work rate relationship during FES-ACE. Peak oxygen uptake for Subject A increased from 0.7 l/min to 1.1 l/min, and peak power output increased from 7 W to 38 W after FES-ACE training. For Subject B, peak oxygen uptake was unchanged, but peak power output increased from 3 W to 8 W. These case studies illustrate potential benefits of FES-ACE in tetraplegia, but also the differences in exercise responses between individuals. Keywords: electrical stimulation; spinal cord injury; cardiopulmonary fitness; rehabilitation; tetraplegi

The Effects and Differences of Sprint Interval Training, Endurance Training and the Training Types Combined on Physiological Parameters and Exercise Performance

Sprint Interval Training (SIT) is a time efficient way in order to elicit similar changes as Endurance Training (ET) on aerobic capacity, with the purpose of the exercise training to alter physiological systems and exceed resting homeostasis to improve and enhance physical work capacity (Hawley et al., 1997), ultimately achieving the most out of each training session, beneficial for health and performance. Research in the area has demonstrated, the positive effects of SIT and ET on some physiological, performance and health parameters, with further needed to establish these adaptations. Yet no research is currently available combining these two training types, in a single training session to obtained potentially greater benefits over the same period of time. The aim of this study was to compare and contrast the effects of SIT, ET and COMB training modalities on physiological parameters and exercise performance after an 8 week training programme. Twenty nine participants volunteered to take part in the 10 week matched paired study, which included an 8 week training programme (age; 35.1±13.1 years, female; 16). All participants undertook a preliminary VO2max test and baseline measurements were taken. Participants were then matched paired into groups, based on sex, VO2peak (ml/kg/min) and resting heart rate (HR), then randomly assigned into a sprint interval (SIT), endurance (ET), a combined (COMB) sprint interval and endurance group or control group (CON). Participants in the SIT group undertook; 5-8 repetitions of 5-second sprints over the 8 weeks, on a cycle ergometer with intervals of 30 seconds, twice, interspaced with 4 minutes rest (<50rpm) three times per week. Those assigned to the ET group carried out cycling for 40 increasing to 60 minutes over the 8 weeks, at 60% of VO2peak equivalent to 78.5% of maximum HR, three times per week. The COMB group undertook combination of the above two protocols based on the pilot study undertaken. The CON group were not required to undertake any training regime. After 4 week and 8 weeks of the training, all participants were required to undertake a VO2max test and baseline measures were re-recorded. Prior to each VO2max test, capillary blood samples were taken for the colorimetric assessment of cholesterol. Two way factorial analysis of variance (ANOVA) were used for statistical analysis with lowest standard deviation (LSD) correction to reduce the type 1 error. Repeated measures ANOVA were used to assess changes within each individual training modality. Results indicate that SIT, ET, COMB and CON groups were not significantly different at baseline in VO2max (p=0.993) and Resting HR (p=0.790) after being match paired into groups by these variables. Significant differences were evident in resting HR between the CON and SIT (p=0.005), CON and ET (p=0.016) as well as CON and COMB (0.026) after the 8 weeks of training. Additionally within the training groups in resting HR; SIT (p=0.006), COMB (p=0.016), ET (p=0.036). Significant differences were seen in relative AT between SIT and CON (p=0.097) after 8 weeks, as well as within the COMB group (p=0.028). Furthermore in diastolic blood pressure after 4 weeks between SIT and COMB (p=0.024), COMB and CON (p=0.029) and after 8 weeks between COMB and ET (p=0.032), COMB and SIT (p=0.033) and COMB and CON (p=0.029). In addition, significance was shown in triglycerides after 8 weeks of training, between ET and CON (p=0.032), SIT and COMB (p=0.025) and COMB and CON (p=0.008) CON. Finally significance was evident in blood glucose between COMB and SIT, halfway (p=0.002) and post training (p=0.019). In terms of age, there was a significant difference in VO2max between those aged 35 years in VO2max after 4 (p=0.022) and 8 weeks (p=0.020) of the training programme. Overall the results indicated that when ET is substituted partly with SIT greater beneficial effects are obtained in numerous variables, demonstrated in this study, which has previously established, SIT is a time efficient training method. Furthermore, a lower duration of sprint i.e. 5 seconds, a more feasible sprint duration, as undertaken in this study provided comparable benefits to previous studies who have adopted longer sprint duration. Finally, these findings on various physiological measures and in a range of ages, indicate that a short time frame or by adopting a combined approach to training, can assist with reducing important health and performance parameters such as blood cholesterol, resting HR, blood pressure and ultimately maximal oxygen consumption and exercise performance, key indicators of cardiorespiratory fitness and health

Effect of a reduction in glomerular filtration rate after nephrectomy on arterial stiffness and central hemodynamics: rationale and design of the EARNEST study

Background: There is strong evidence of an association between chronic kidney disease (CKD) and cardiovascular disease. To date, however, proof that a reduction in glomerular filtration rate (GFR) is a causative factor in cardiovascular disease is lacking. Kidney donors comprise a highly screened population without risk factors such as diabetes and inflammation, which invariably confound the association between CKD and cardiovascular disease. There is strong evidence that increased arterial stiffness and left ventricular hypertrophy and fibrosis, rather than atherosclerotic disease, mediate the adverse cardiovascular effects of CKD. The expanding practice of live kidney donation provides a unique opportunity to study the cardiovascular effects of an isolated reduction in GFR in a prospective fashion. At the same time, the proposed study will address ongoing safety concerns that persist because most longitudinal outcome studies have been undertaken at single centers and compared donor cohorts with an inappropriately selected control group.&lt;p&gt;&lt;/p&gt; Hypotheses: The reduction in GFR accompanying uninephrectomy causes (1) a pressure-independent increase in aortic stiffness (aortic pulse wave velocity) and (2) an increase in peripheral and central blood pressure.&lt;p&gt;&lt;/p&gt; Methods: This is a prospective, multicenter, longitudinal, parallel group study of 440 living kidney donors and 440 healthy controls. All controls will be eligible for living kidney donation using current UK transplant criteria. Investigations will be performed at baseline and repeated at 12 months in the first instance. These include measurement of arterial stiffness using applanation tonometry to determine pulse wave velocity and pulse wave analysis, office blood pressure, 24-hour ambulatory blood pressure monitoring, and a series of biomarkers for cardiovascular and bone mineral disease.&lt;p&gt;&lt;/p&gt; Conclusions: These data will prove valuable by characterizing the direction of causality between cardiovascular and renal disease. This should help inform whether targeting reduced GFR alongside more traditional cardiovascular risk factors is warranted. In addition, this study will contribute important safety data on living kidney donors by providing a longitudinal assessment of well-validated surrogate markers of cardiovascular disease, namely, blood pressure and arterial stiffness. If any adverse effects are detected, these may be potentially reversed with the early introduction of targeted therapy. This should ensure that kidney donors do not come to long-term harm and thereby preserve the ongoing expansion of the living donor transplant program.&lt;p&gt;&lt;/p&gt