The effect of surrounding avatars’ speed and body composition on users’ physical activity and exertion perception in VR GYM

Drug treatment has traditionally been considered the gold standard therapy for osteoporosis, due to limited efficacy of lifestyle interventions such as low to moderate intensity exercise and dietary interventions. Recently, however, the LIFTMOR (Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation) trial demonstrated that a novel, high-intensity progressive resistance and impact training (HiRIT) program markedly improved bone and functional indices of falls and fracture in postmenopausal women with low to very low bone mass. While men also suffer from osteoporosis, prevalence is lower than in women, leading to fewer studies in men. To determine if the same exercise protocol would be effective for older men with low bone mass, the LIFTMOR-M (LIFTMOR for Men) trial was conceived. Another recent development in the field of osteoporosis was the bioDensity™ exercise machine, designed theoretically to load bone via isometric axial compression (IAC). Although the manufacturers claimed osteogenic efficacy, no high-quality evidence existed. By examining the effects of two novel exercise programs on musculoskeletal health and risk factors for falls in a poorly researched population, our findings will contribute evidence towards developing efficacious non-pharmacological osteoporosis therapy. The current Thesis reports the results of the eight-month LIFTMOR-M exercise intervention trial. That is, we compared the efficacy, compliance and safety of supervised HiRIT in comparison to supervised machine-based IAC exercise or control (usual activities) on indices of bone strength and risk factors related to falls and fracture susceptibility in middle-aged and older men with low areal bone mineral density (aBMD). The Thesis comprises four publications, presented as one published manuscript, one manuscript accepted for publication and two manuscripts under review. The published manuscript (Chapter 3) is the protocol paper outlining the study design, recruitment, exercise interventions, control activities, and primary and secondary outcomes of LIFTMOR-M. The trial was a three-arm, eight-month, semi-randomised controlled exercise intervention trial. Community-dwelling, middle-aged and older men (≥ 45 years) with low aBMD at the lumbar spine (LS), total hip and/or femoral neck (FN) (T-score ≤ - 1.0) were recruited. Eligible participants were randomly assigned to eight months of twice-weekly, supervised HiRIT (five sets of five repetitions, ≥ 80-85% of one repetition maximum) or machine-based IAC exercise (five-second isometric contraction, rating of perceived exertion ≥ 16) stratified on presence or absence of osteoporosis medications. The self-selected, non-randomised control group, who received no intervention, were instructed to maintain customary dietary and physical activity patterns. Participants underwent testing at baseline and eight months. Outcomes included: whole body and regional bone, muscle and fat; anthropometry; indices of functional performance; thoracic kyphosis; and vertebral fracture assessment. Compliance and adverse events (falls, fractures, and injuries) were monitored. In the second manuscript (Chapter 4), we reported the primary outcome (FN aBMD) and secondary outcomes of regional aBMD, calcaneal ultrasound parameters, anthropometrics, body composition, physical performance, compliance, and adverse events. We found that HiRIT improved LS aBMD, trochanteric aBMD, broadband ultrasound attenuation and stiffness index of the calcaneus, lean mass, and five physical performance measures compared to loss or minimal change for control. IAC improved lean mass and one physical performance measure compared with control. HiRIT effects were superior to IAC for LS aBMD, stiffness index of the calcaneus and five-times sit-to-stand performance. Compliance and retention were high, and there were few adverse events. In the subsequent manuscript (Chapter 5), secondary outcomes of bone strength indices at the proximal femur, tibia and radius are presented. We found that HiRIT provided a positive stimulus to cortical bone at the medial FN compared with IAC and control, and both HiRIT and IAC preserved bone strength at the distal tibia and distal radius in comparison to control. The final manuscript (Chapter 6) presents clinical measures of thoracic kyphosis with inclinometry, Cobb angle of kyphosis and vertebral fracture assessment for a sub-group of LIFTMOR-M exercise intervention participants. We observed that both HiRIT and IAC improved clinical measures of thoracic kyphosis, and HiRIT improved Cobb angle of kyphosis, at eight months. HiRIT had no incident fractures nor progression of prevalent vertebral fractures over the course of the trial. By contrast, IAC experienced five incident vertebral wedge fractures and one wedge fracture progressed. In summary, the current Thesis reports the positive effects of twice-weekly, supervised HiRIT on bone, muscle, kyphosis, incident vertebral fracture, and functional indices of falls and fracture risk in older men with osteopenia and osteoporosis. Furthermore, strong compliance and retention suggests HiRIT training was appealing and well tolerated, with no incident fractures or major adverse events across the intervention period. IAC may improve lean mass and posture to a lesser extent but does not improve or preserve bone at clinically relevant sites, nor prevent incident vertebral fracture. Based on these findings, we conclude that HiRIT is a safe, efficacious and appealing exercise program, superior to IAC, for the management and rehabilitation of osteopenia and osteoporosis in middle-aged and older men.

Reliability of acute training responses elicited by exhaustive work intervals prescribed with the delta concept

This study compared measures of Rating of Perceived Exertion (RPE), based on the OMNI-RES RPE scale, to three different high-velocity resistance exercise protocols. Twelve older women (63 ± 3.0 yrs) performed 3 upper and lower body resistance exercise protocols. Each protocol involved 3X10 rep sets at a 10 repetition maximum load (3 sets of 10 continuous reps); 3 sets of 10 discontinuous reps (5 second rest interval); 3 sets of 10 discontinuous reps (15 second rest interval). No significant (p > 0.05) difference on RPE was observed among the three protocols. OMNI-RES reliability between tests was easy and positive in both exercises. Compared to baseline, RPE increased continuously (p < 0.05) after the second and the third set in of all the protocols. It was concluded that: 1) RPE is the same independent of the protocol; 2) the OMNI-RES RPE scale is reliable; and 3) RPE increase as the number of sets. Key Words: Elderly. Exercise Resistance. Rating of Perceived Exertion.

Within the laboratory setting, high intensity interval training (HIIT) can elicit physiological adaptations similar to traditional moderate intensity continuous training (MICT) with the important advantage of a reduced total exercise volume and time commitment. However, researchers have argued that HIIT is not a viable public health strategy because it is too demanding to be maintained by non-athletic populations (Biddle and Batterham, 2015). The aim of this thesis was to investigate the effect of real-world HIIT interventions on adherence and cardio-metabolic health risk factors. Furthermore this thesis investigates the feasibility and perceptual responses to home-based wholebody HIIT as a strategy to remove many of the major barriers to exercise. In Chapter 3, 82 previously sedentary males (n=26) and females (n=56) aged 18-65 (28±10 y, BMI 25±3 kg.m-2) participated in the study. In a randomised cross-over design, whereby participants completed either 6 weeks of 30HIT (4-8x30s sprint with 120s active recovery) and 6-weeks of 60HIT (6-10x60s sprint with 60s active recovery). Participants then completed a 4-week washout period before completing the alternative intervention. Training sessions were completed on a Wattbike, 3 times per week. VO2peak, body composition (DXA), glycaemic control (oral glucose tolerance test (OGTT) and arterial stiffness (aortic pulse wave velocity (aPWV)) were assessed pre and post each 6-week training phase. VO2peak increased post intervention in 30HIT and 60HIT (P 0.05). In Chapter 4, 154 patients (males: n=88), females: n=66) who were eligible for a UK exercise referral scheme (ERS) (inactive and at least one health risk factor) were recruited. Participants chose either 12-weeks ERS (encouraged to achieve 150min/wk of moderate-intensity exercise, with reduced cost gym membership) or Home-based HIIT (4-9x1min intervals interspersed with 1 min rest, using body weight exercises). Adherence and compliance to the programme were monitored using a heart rate monitor. VO2peak, body composition (DXA), glycaemic control (OGTT) and arterial stiffness (aPWV) was recorded at baseline, post-intervention (12-weeks) and 3-months postintervention (follow-up). Perceptions of the programme were evaluated using an online interview. 56% (n=87) of eligible participants chose Home-based HIIT in preference to ERS. At baseline Home-based HIIT had a lower VO2peak than ERS (P=0.034). ERS and Home-based HIIT had a similar adherence (HIIT 39%, ERS 53% P=0.298) and compliance to the prescribed programme (HIIT 30%, ERS 47% P=0.331). VO2peak increased post-intervention (P<0.001) in both groups and this was maintained at follow-up (P=0.287). The interview revealed Home-based HIIT was positively received, and the convenience of the programme reduced some of the perceived barriers to exercise. Finally, in Chapter 5, 27 recreationally active (≥1 hr exercise/wk) participants (male/female: n=13/14, age: 223y, BMI: 24.32.4, VO2peak: 42.27.2 ml.min1.kg-1) completed a randomised counter-balanced cross over design. To assess the acute physiological (heart rate and lactate) and perceptual responses (feeling scale, felt arousal scale and rate of perceived exertion) to four different HIIT protocols (Ergo-60:60: cycling 10x60s at 100%Wmax with 60s rest, BW-60:60: whole-body exercise 10x60s with 60s rest, SM-20:10:following a social media video 20x20s with 10s rest, SM-40:20: following a social media video 15x40s with 20s rest). BW-60:60 resulted in significantly higher interval heart rate peak (P<0.001) compared to all other protocols, and a significantly higher change in lactate compared to SM-20:10 (P<0.001). No differences were observed between groups when reporting lowest recorded feeling scale (P=0.292), but differences in the feeling scale profile during exercise did exist between the protocols used within the research (Ergo-60:60 & BW-60:60) and the social media protocols. Greater post-session enjoyment was reported in BW-60:60 compared to Ergo-60:60 (P=0.004) despite using the same work:rest ratio. In conclusion, this thesis provides strong evidence that sedentary or at risk participants are able to complete HIIT at the correct prescribed intensity to induce health benefits in a free-living environment. Furthermore, Home-based HIIT was an attractive option for at-risk patients referred to an ERS, and had similar adherence to the traditional exercise prescription guidelines. Additionally, body-weight HIIT and social media videos are promising enjoyable options, compared to traditional cycling-based HIIT. Therefore we provide strong evidence that the prescription of HIIT, especially a Home-based HIIT programme using body-weight exercises, is both effective and feasible for a non-athletic population in the real world.

Objective To discuss the relationship between heart rate (HR), rate of perceived exertion (RPE) and oxygen consumption in therapeutic exercises for stroke patients. Methods Eighteen stroke patients a-ble to walk independently participated in the test. K4b2 Pulmonary Function Equipment was used to record their heart Rates(min-1)and specific oxygen consumption(ml·min-1·kg-1)during the following exercises:relaxed sitting,sit-to-stand transfers, leaning against a wall and elevating the hips (strength training of the gluteus maximus) , raising the unaffected leg while the affected leg is weight bearing, raising the affected leg while the unaffected leg is weight bearing, climbing up and down stairs, and walking 60 meters. RPE was surveyed after each exercise. Results The correlation between HR and oxygen consumption was moderate (r = 0.618, P≤0.001), but it was weak between RPE and oxygen consumption (r = 0.325 ,P≤0.001). Conclusion Heart rate is a better index than RPE for eval-uating exercise intensity with stroke patients able to walk independently. Key words: Stroke ; Oxygen consumption ; Heart rate ; Rate of perceived exertion ; Exercise intensity ;

Exercise in hot environments increases body temperature and challenges the function of cardiovascular, metabolic and thermoregulatory systems. Elevated body temperature as a consequence of prolonged and/or intense exercise impairs athletic performance and increases the risk of heat illness and serious medical conditions. Pre-exercise cooling techniques have been used to lower body temperature and increase heat storage capacity during exercise. Head, neck and wrist cooling have also been employed to reduce physiological strain in hot environments. Although the majority of these methods have proven useful, some are impractical for use during exercise when heat strain is most pronounced. Hand cooling during exercise has the potential to alleviate these impracticalities and attenuate increases in body temperature due to the hands large surface to mass ratio, low metabolic heat production, large blood supply and rapid cooling rates. Reductions in body temperature after bouts of exercise and improvements in exercise performance have been observed using various hand cooling protocols. However, the effectiveness of hand cooling during exercise in a hot environment and the mechanisms of action are unclear. The purpose of the study was to quantify physiological and perceptual responses to hand immersion in water during recumbent cycling in a hot environment. In a randomised control design 7 well-trained males (body mass 79.8 s 6.3 kg; stature 182 s 5 cm; age 23 s 3 years; recumbent cycling V I‡O2peak 41 s 5 ml•kg-1•min-1) who were naA¯ve to the study aims provided informed consent to participate in 3 trials. Participants immersed their hands in 8, 14 and 34°C water whilst cycling at an intensity (W) equivalent to 50% V I‡O2peak for 60 min in an environmental chamber maintained at 35°C 50% relative humidity. Intestinal and 4-site mean skin temperature and heart rate were monitored continuously and mean-averaged over 5 minute intervals. Rating of perceived exertion and thermal strain were assessed every 5 minutes. Data was assessed for normality and homogeneity of variance. The likelihood (% chance) of between group differences was assessed using a magnitude-based approach, Cohen's standardised difference score (d = 0.20 small, 0.5 moderate and 0.8 large effect) and 90% confidence intervals for [d]. Change in intestinal temperature was likely (84%) less in 8°C; 0.43 s 0.16°C versus 34°C; 0.55 s 0.16°C after 15 min; d = 0.73 [-0.19 to 1.65] and very likely (98%) less in 8°C; 0.78 s 0.28°C versus 34°C; 1.22 s 0.16°C after 40 min d = 1.36 [0.47 to 2.25]. Change in mean skin temperature was likely (87%) less in 8°C; -0.05 s 0.39°C versus 34°C; 0.31 s 0.46°C; d = 0.81 [0.09 to 1.71] after 5 min, very likely (98%) less after 15 min; -0.09 s 0.72°C versus 0.77 s 0.30°C; d = 1.24 [0.45 to 2.03] and onwards to cessation of exercise. Percentage of peak heart rate was likely (94%) lower in 8°C; 87 s 4% versus 34°C; 90 s 5% from 25 min onwards; d = 0.69 [0.18 to 1.20]. After 5 min of exercise rating of perceived exertion was likely (77%) lower  in 8°C; 12.6 s 1.0 versus 34°C 13.4 s 1.7; d = 0.61 [-0.36 to 1.57] but was likely similar from 25 min onwards. Perception of thermal strain was likely (92%) lower in 8°C; 6.5 s 0.5 versus 34°C; 7.2 s 0.4 after 5 min exercise; d = 0.81 [0.09 to 1.71] and was almost certainly (>99%) lower; 7.3 s 0.7 versus 8.0 s 0.7 for the remainder of the trial; d = 1.21 [0.65 to 1.77]. Similar beneficial effects were observed for 14°C versus 34°C immersion but the magnitude of the effects was smaller than 8°C immersion. Small-to-moderate differences were observed between 8°C and 14°C immersion. The findings suggest that hand cooling during fixed moderate-intensity cycling in a hot environment has the potential to alleviate increases in body temperature, cardiovascular demand and perceptions of exertion and thermal strain. Greatest effects were observed when the hands were immersed in 8°C water compared with 14°C. Augmented heat loss at the palm-water surface might enable cooler blood to return to core and shell regions; increasing the thermal gradient between active tissue and blood thus improving internal heat transfer, maintaining a wide core to skin temperature gradient and reducing heat storage. Limiting the increase in body temperature might have lowered cardiovascular demands by reducing the requirement for cutaneous vasodilation thus lowering physiological strain. These combined effects are manifested in lowered perceptions of exertion and thermal strain. The findings from this study suggest that endurance exercise in hot environments might be improved by hand cooling and future research should investigate its effectiveness during cycling and running performance.

The intermittent exercise pattern associated with soccer makes analysis of the demands of the sport more complex than in many individual sports. The aim in this thesis was to determine the physiological and metabolic responses to soccer-specific exercise. The demands associated with elite level match-play were evaluated by techniques of motion-analysis. Laboratory based soccer-specific intermittent exercise protocols were then devised to determine the physiological strain associated with soccer and investigate the effects of increased ambient temperature and whole body pre-cooling on performance. The work-rate profiles of elite South American soccer players and English Premier League players, performing in international and club level respectively, were determined. English Premier League players covered a greater total distance during a game than the South American players (P< 0.05). Differences were found for the total distance covered for playing positions with midfield players covering larger distances than forwards. Defenders covered a greater distance jogging backwards than forward players with forwards sprinting a greater distance than defenders. Work-rate was reduced in the second half of the game for all player. The total distance covered by the international players was done mainly at submaximal intensities. High intensity exercise was infrequent and bouts were of short duration. No significant correlations were observed between the work-rate profile and anthropometric charactersitics of individuals. The use of the doubly-labelled water technique to indicate the energy expenditure during soccer match-play was investigated. The doubly-labelled water technique cannot determine energy expenditure during a soccer match as the rate of turnover of the isotopes is too small to allow the accurate estimation of energy expended. Laboratory based soccer-specific intermittent protocols elicited physiological responses that were similar in magnitude and pattern to soccer match-play. Physiological demands fluctuated with exercise intensity during intermittent exercise. Oxygen consumption and heart rate were not significantly different during soccer-specific intermittent exercise and steady-rate exercise at the same average intensity. Rectal temperature did not differ significantly between the two protocols, although intermittent exercise performance resulted in a greater rise in rectal temperature as the protocol progressed (P< 0.05). Sweat production did not differ significantly between the two exercise sessions, though the rating of perceived exertion was significantly higher (P< 0.05), for the session as a whole, during intermittent exercise. Intermittent exercise performance at 26 ° C did not result in significant increases in the physiological, metabolic or thermoregulatory responses when compared to intermittent exercise at 20 ° C. The physiological and metabolic responses were also similar when intermittent exercise was performed after a whole body pre-cooling manoeuvre. Rectal temperature was lowered by the pre-cooling strategy prior to exercise (- 0.6 ± 0.6 ° C, P< 0.05). Rectal temperature during exercise was only significantly lower after pre-cooling than during exercise at 26 ° C. No significant differences were observed in rectal temperature during exercise between the normal and pre-cooled condition. The increase in rectal temperature during the second half of the protocol was significantly greater than the increase observed at 26 ° C or under normal conditions. This may be a consequence of an altered thermoregulatory response due to the pre-cooling manouvre. In conclusion, the work-rate demands of soccer seem to be predominantly aerobic in nature with anaerobic bouts and the performance of specific match activities increasing the demands placed on players. The demands of intermittent exercise are not significantly different from continuous work performed at the same average intensity though there is tentative evidence for a decrease in the efficiency of the thermoregulatory system during intermittent work. No adverse effects upon intermittent exercise performance were noted under conditions of moderate heat stress, while any thermoregulatory benefits of whole body pre-cooling during intermittent work are probably only transient.

Physiologic parameters and perceived exertion with local muscle fatigue in postpolio subjects.

The purpose of this experiment was to compare the pre-exhaustion method (PRE) to the inverse order in leg press (LP) and leg extension (LE) exercises over the volume of maximum repetitions (RM) and ratings of perceived exertion (RPE). Thirteen trained men (22 ± 3.2 years; 84.7 ± 9 kg; 180 ± 8 cm) were submitted to four data collection sessions. After the determination of 8RM load, 96 hours of interval was respected for application to the sequence A, LP before LE, and after 72 hours sequence B (PRE) was executed, LE before LP. One set of each exercise were accomplished with a 20 seconds rest interval for transition between exercises. The procedure was accomplished four times with fixed intervals in two minutes. The number of RM and RPE (OMNI-RES) were collected after each set of each exercise. The results presented the total volume of RM and the mean number of RM in the exercise LE significantly lower in the sequence A (total volume = 38.6 ± 7.3; mean number of RM CE = 3.57 ± 1.19) when compared to the sequence B (total volume = 46.9 ± 8.4; mean number of RM CE = 6.69 ± 1.33). These data indicate that the order of PRE promotes the accomplishment of a larger total volume of training when compared to the inverse order without alterations in RPE.

To investigate the impact of college students' evening exercise on their sleep quality, so as to provide a scientific basis for college students to choose an appropriate method of exercise and improve their sleep quality. From September to October in 2012, Multi-stage cluster random sampling method was used to select the 5997 college students in Anhui province. The status of college students' exercise and their sleep quality were investigated by the general situation questionnaire, Physical activity rating scale-3(PARS-3), Rating of perceived exertion(RPE) and Pittsburgh sleep quality index(PSQI). Kruskal-Wallis test was used to analyze the impact of evening exercise on sleep quality and multivariate unconditional logistic regression was used to analyze the factors of sleep quality in evening excise students. The median of PSQI total score among 5806 college students was 5 and 1030(17.7%) students had poor sleep quality. The median of the PSQI scores was the same (5 points) for evening exercise group, daytime exercise group,daytime and evening exercise group and non-exercise group (1406, 1514, 1244, 1642 respectively). The difference was not statistically significant (χ(2) = 2.80, P = 0.42). Compared to non-exercise population, the OR (95%CI) value of evening exercise' impact on sleep quality was 0.90(0.73-1.10). Compared to very light evening exercise, the OR (95%CI) value of moderate and large amount of evening exercise' impact on sleep quality was 0.58 (0.44-0.75) and 0.67 (0.48-0.93) respectively; Compared to other sports, the OR (95%CI) value of badminton, rope skipping and jogging' impact on sleep quality was 0.72 (0.55-0.93), 0.38 (0.21-0.70) and 0.76 (0.60-0.95) respectively and they were all protective factors of sleep quality. Compared to small exercise intensity, the OR (95%CI) value of moderate, vigorous and very vigorous exercise intensity' impact on sleep quality was 1.68 (1.13-2.52), 2.38 (1.48-3.83) and 3.18 (1.72-5.90) respectively and they were harmful factors of sleep quality. There was no impact of evening exercise on sleep quality for college students. Type of sports should be adequately chosen for evening exercise. College students can take moderate and large amount of evening exercise but should avoid activities of vigorous intensity.

Athletes exercising in temperate and warm conditions have elevated sweat rates, and ad-libitum fluid intake is typically in-sufficient to adequately replace sweat losses, resulting in hypohydration. Hypohydration of >2% body mass impairs aerobic exercise performance in temperate and warm conditions, with the impairment in performance likely due to a combination of physiological and perceptual mechanisms.The methods used in previous research to induce hypohydration (i.e. fluid restriction, heat exposure, diuretic use) have meant subjects were aware of manipulations to their hydration status. More recent studies have aimed to blind subjects to manipulations in hydration status via intravenous infusion or intragastric infusion of fluids. While these studies were successful in blinding subjects to manipulations in hydration status, they could not ascertain whether knowledge of hydration status contributed to the negative effect of hypohydration on exercise performance. Thus, the first aim of this thesis was to determine whether knowledge of hypohydration influenced exercise performance (Chapter 3). Changes typical of hypohydration (i.e. increased heart rate, rating of perceived exertion, gastrointestinal temperature, serum osmolality and thirst, and decreased plasma volume) were apparent with hypohydration at the end of 2 h of steady-state cycling and did not differ between blinded and unblinded groups. Hypohydration of ~3% body mass similarly impaired cycling time trial performance (-10% unblinded vs -11% blinded) in the heat in trained cyclists, regardless of knowledge of hydration status.There is a lack of research assessing exercise-induced hypohydration on running performance in a temperate environment, a common scenario for intermittent games players and endurance athletes that regularly exercise in temperate environments with insufficient fluid intake. Given the weight-bearing nature of running, the negative effects of hypohydration might be offset by the positive effects of body mass loss. Therefore, the purpose of Chapter 4 was to investigate the effect of hypohydration on 3 km running performance in a temperate environment. Despite the body mass loss (~1.7 kg) associated with a negative fluid balance, hypohydration of ~2% body mass impaired 3 km running time trial performance by ~6%.Although the negative consequences of hypohydration on exercise performance are well-known, endurance athletes regularly finish training sessions/events with significant hypohydration, and field studies have shown an inverse relationship between body mass loss and endurance performance (i.e. the greater the exercise-induced body mass loss, the quicker the finishing time). This led to the hypothesis that a familiarisation/adaptation to exercise-induced hypohydration is conceivable. Thus, the third research question of this thesis was proposed, can athletes familiarise to a limited number of repeated exercise-induced dehydration exposures to reduce the negative effect of hypohydration on performance (Chapter 5). Five repeated exposures to exercise-induced dehydration (~2% body mass) did not reduce the negative effects of hypohydration on 3 km running performance in intermittent games players.Research assessing rehydration from exercise-induced dehydration is often poorly controlled. Research typically informs subjects of the purpose of assessing rehydration, or influences behaviour by providing fluids, thus influencing fluid intake behaviours. Therefore, the final aim of this thesis was to determine if athletes rehydrate within 20 h of an intermittent exercise session, with subjects unaware that hydration status was being assessed. Subjects were also permitted to drink ad-libitum water during the exercise session and continue recording dietary intakes in a free-living environment for 20 h post-exercise (Chapter 6). Intermittent games players lost ~2% body mass during an intermittent running session when access to ad-libitum fluid was permitted. A small degree of hypohydration likely remained present 20 h post-exercise, evidenced by decreased body mass and increased urine osmolality (concentration) the morning post-exercise, suggesting specific rehydration strategies may be required for intermittent games players.From this thesis, it can be concluded that hypohydration (~3% body mass) impaired cycling performance in the heat, regardless of knowledge of hydration status (Chapter 3). Despite the body mass loss associated with a negative fluid balance, hypohydration of ~2% body mass impaired 3 km running time trial performance in a temperate environment (Chapter 4). A small number of repeated exposures to exercise-induced dehydration did not attenuate the performance decrement from hypohydration on running time trial performance (Chapter 5). Rehydration from intermittent exercise was likely not achieved within 20 h post-exercise, suggesting rehydration strategies may be required in team sports where training is completed daily (Chapter 6).

1. Maximal aerobic exercise capacity, submaximal endurance exercise performance, and exercise haemodynamics have been studied in sixteen patients with mild to moderate essential hypertension during treatment with captopril and atenolol. 2. Administration of atenolol (1 x 100 mg day-1) or captopril (1 x 100 mg day-1) for 6 weeks resulted in similar supine and erect systolic and diastolic blood pressures. Heart rate was significantly lower during atenolol treatment. 3. Exercise heart rate and systolic blood pressure were significantly lower during atenolol than during captopril treatment, exercise diastolic blood pressure (at 100W) did not differ significantly. With atenolol exercise cardiac output was significantly lower and exercise stroke volume significantly higher than with captopril. 4. Maximal work rate, maximal oxygen consumption and maximal heart rate were significantly lower during atenolol than during captopril treatment (respectively 6%, 8% and 25%). Maximal respiratory exchange ratio and lactate concentration did not differ. 5. No statistically significant difference in submaximal endurance time between atenolol and captopril was found. Endurance time was reduced by 19% during atenolol and by 13% during captopril as compared with placebo. No difference in rating of perceived exertion between atenolol and captopril was present. 6. The results indicate that atenolol will reduce blood pressure during exercise more effectively than captopril in patients with hypertension. The limitation of submaximal endurance exercise performance by both agents is of similar magnitude. This may be regarded as an unwanted side effect in certain physically active patients with hypertension.

BackgroundPhysical inactivity is a growing risk factor worldwide, therefore getting people into sports is necessary. When prescribing physical activity, it is essential to recommend the correct training intensities. Cardiopulmonary exercise testing (CPX) enables precise determination of individuals’ training intensities but is unavailable for a broad population. Therefore, the Borg scale allows individuals to assess perceived exertion and set their intensity easily and cost-efficiently. In order to transfer CPX to rating of perceived exertion (RPE), previous studies investigated RPE on specific physiological anchors, e.g. blood lactate (bLa) concentrations, but representativeness for a broad population is questionable. Some contradictory findings regarding individual factors influencing RPE occur, whereas univariable analysis has been performed so far. Moreover, a multivariable understanding of individual factors influencing RPE is missing. This study aims to determine RPE values at the individual anaerobic threshold (LT2) and defined bLa concentrations in a large cohort and to evaluate individual factors influencing RPE with multivariable analysis.MethodsCPX with bicycle or treadmill ergometer of 6311 participants were analyzed in this cross-sectional study. RPE values at bLa concentrations 2 mmol/l, 3 mmol/l, 4 mmol/l, and LT2 (first rise in bLa over baseline + 1.5 mmol/l) were estimated by spline interpolation. Multivariable cumulative ordinal regression models were performed to assess the influence of sex, age, type of ergometry, VO2max, and duration of exercise testing on RPE.ResultsMedian values [interquartile range (IQR)] of the total population were RPE 13 [11; 14] at 2 mmol/l, RPE 15 [13; 16] at 3 mmol/l, RPE 16 [15; 17] at 4 mmol/l, and RPE 15 [14; 16] at LT2. Main influence of individual factors on RPE were seen especially at 2 mmol/l: male sex (odds ratio (OR) [95%-CI]: 0.65 [0.587; 0.719]), treadmill ergometry (OR 0.754 [0.641; 0.886]), number of stages (OR 1.345 [1.300; 1.394]), age (OR 1.015 [1.012; 1.018]), and VO2max (OR 1.023 [1.015; 1.030]). Number of stages was the only identified influencing factor on RPE at all lactate concentrations/LT2 (3 mmol/l: OR 1.290 [1.244; 1.336]; 4 mmol/l: OR 1.229 [1.187; 1.274]; LT2: OR 1.155 [1.115; 1.197]).ConclusionOur results suggest RPE ≤ 11 for light intensity, RPE 12–14 for moderate intensity, and RPE 15–17 for vigorous intensity, which slightly differs from the current American College of Sports Medicine (ACSM) recommendations. Additionally, we propose an RPE of 15 delineating heavy and severe intensity domain. Age, sex, type of ergometry, duration of exercise, and cardiopulmonary fitness should be considered when recommending individualized intensities with RPE, primarily at lower intensities. Therefore, this study can be used as a new guideline for prescribing individual RPE values in the clinical practice, predominantly for endurance type exercise.

Ratings of perceived exertion (RPE) and session-RPE methods are widely used as estimate of exercise intensity and to quantify training load in sport activities. However, no information is available in fitness activities although people are often engaged in high intensity physical activities and monitoring individual responses to the training stimulus could provide important feedback on the adaptation to training. Therefore, the purpose of this study was to verify the use of session-RPE using Edwards’ summated heart rate (HR)-zone method as a criterion measure (Herman et al., 2006). After giving their informed consent of participations, 20 volunteers (M=5; F=15; mean age: 21±10 years) practicing regular group-based fitness activities (i.e., 3 weekly sessions of Fit-boxe), participated in the study. Heart rate during the fitness lessons and CR-10 Borg’s scale 30 minutes after the end of the exercise session were recorded. Edwards’ HR method was determined by expressing the HR recordings as percentages of the athlete’s theoretical maximal HR (220-age), multiplying by a specific factor the accumulated time (minutes) in 5 HR zones (50–60% of HRmax=1; 60–70% of HRmax=2; 70–80% of HRmax=3; 80–90% of HRmax=4; 90–100% of HRmax=5), and summating the scores. Session-RPE was calculated multiplying RPE value by the training duration (minutes). RPE recorded 30 minutes after the end of the lesson was 6.1±1.4 points. High and significant correlation (r = 0.72; 95% CI = 0.41-0.88; p = 0.0006) emerged between Edwards’ HR (145.5±32.6 AU) and the session-RPE (247.7±71.6 AU) methods. Results from this preliminary study show that session-RPE can be a useful and inexpensive tool to quantify internal training load in fitness activities, and instructors could use this instrument to monitor their clients, especially when considering the high inter-individual variability of group-based fitness activities.

Introduction: Evidence exists that cocoa flavanol (CF) can increase nitric oxide synthesis. This promotes vasodilation and several physiological processes, such as mitochondrial respiration and biogenesis, glucose uptake and SR-Ca handling, that may support exercise performance1. Moreover, CF intake is also known for its antioxidative capacities (in vitro and in vivo), resulting in reduced levels of oxidative stress2. During exhaustive exercise, free radical production increases dramatically, resulting in an altered redox state in the muscle, which possibly inhibits muscle contraction3. Acute intake of antioxidants may help neutralize free radicals and therefore directly prevent a decline in exercise performance4. Moreover, increased antioxidative capacity may repress the formation of peroxinitrite, which may elevate NO availability5. The aim of this study was to examine the effect of CF intake on 1) NO production in response to exhaustive exercise, 2) exercise-induced changes in antioxidative capacity and oxidative stress and 3) exercise performance in well-trained athletes. Materials and methods: Twelve well-trained men(PL36) (mean ± SD age, height, mass, VO2max: 30 ± 3 years, 177.9 ± 8.8 cm, 72.8 ± 7.8 kg , 63.0 ± 3.5 ml/kg/min) participated in this randomized, double-blind, cross-over study. Participants performed two 30-min time trials (TT) 1.5 and 3 hours after CF intake (900 mg) or placebo intake (PL 13 mg CF), interposed by passive rest. Lactate, glucose, heartrate, rate of perceived exertion (RPE) and power output were measured during the TTs. Blood samples were drawn at baseline, before and immediately after the two TTs and analysed for trolox equivalent antioxidative capacity (TEAC), Uric acid (UA), malonaldehyde (MDA), arginine and citrulline. TT performance was compared between PL and CF by paired t-test. Pacing strategy during TT and blood markers were analysed by repeated measured ANOVA. Results: Time to complete TT1 tended to be lower after CF intake compared to PL intake (29’13” ± 1’19” CF vs. 29’47” ± 1’58” PL, p=.09). After 25 minutes, a significant higher power output was observed in CF compared to PL. No differences in TT2 performance was observed between CF and PL. Glucose, lactate, heartrate and RPE increased significantly during both TTs, but were unaffected by CF intake. TEAC and UA significantly increased after both TTs. CF intake increased TEAC and UA, compared to PL intake (Figure 1A). MDA was increased by exercise, but remained unaffected by CF intake. Arginine was significantly lowered by exercise. Before TT1, CF intake tended to increase arginine, compared to PL intake. After TT1, arginine levels did not differ between CF and PL. Citrulline significantly increased by exercise, but was not altered by CF intake (Figure 1B). Conclusion: Acute CF intake tended to enhance performance on a TT 1.5 hours after intake. Increased power output was detected at the end of the TT. Exercise acutely increased antioxidative capacity, lipid peroxidation (marker of oxidative stress) and NO production (increased citrulline and decreased arginine). CF intake increased antioxidative capacity, but did not alter lipid peroxidation. CF intake tended to increased arginine levels, known to augment NO production and possibly explaining the improved exercise performance.