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certified coaches (CC)-68.09±12.30%; beginning PE teachers (BT)–62.46±10.24%; graduating PE teachers (GT)-67.01±9.46%. There was a significant difference in the passing rates between BC and CC (BC-3.1% vs CC-17.2%, p.05). The difference in passing rates between BT and GT was not significant (BT-5.9% and GT-11.3%, p =.05). Even at 80th percentile, none of the groups attained passing scores. At 90th percentile, only the CC and GT attained passing scores. Discussion Results showed that the majority of coaches and PE teachers in Singapore have inadequate hydration and fluid replacement knowledge and they were largely unfamiliar with the NATA and ACSM guidelines on fluid replacement. The lack of adequate exercise hydration knowledge among coaches and PE teachers puts the health and well-being of youth exercising in the hot and humid climate of Singapore at risk. It is important to bridge current hydration knowledge gaps among coaching and PE practitioners and step up education programmes to empower youths with appropriate exercise hydration
knowledge. Future studies focusing on coaches’ education on hydration and fluid replacement are essential. References Casa DJ, Armstrong LE, et al. (2000). Journal of athletic training 35(2): 212-224. Ransone J & Dunn-Bennett LR (1999). Journal of athletic training 34(3):
267-271. Sawka MN, Burke LM, et al. (2007). Medicine and science in sports and exercise 39(2): 377-390.
08:30 - 10:00 Oral presentations OP-PM49 Training and Testing [TT] 3
COMPARING HEART RATE MONITOR AND ACCELEROMETER TO DETERMINE ENERGY EXPENDITUREDyrstad, S.1, Hausken, K.2 Univesity of Stavanger Introduction Heart rate monitors are an accurate tool to measure heart rate response to physical activity. It has also become a common tool to measure energy expenditure. During the last 15 years accelerometers have become one of the most common objective methods to assess physical activity. Understanding how different tools measure physical activities differently is important in order to compare methods and interpret data correctly. The purpose of the study was therefore to compare the estimation of energy expenditure from heart rate monitors and accelerometer in interval running and zumba (a Latin dance-inspired fitness program). Methods A total of 26 sports students (15 females) with a mean age of 21.8±2.4 (SD) years, wearing both heart rate monitor and accelerometer, carried out two different training sessions: A 45 min interval running session containing 12 min warmup, 4x4 min running, 90-95% of max heart rate, with 3 min jogging, 70% of max heart rate between each interval, and 5 min cooldown. Zumba 60 min containing 5 min warmup, thereafter 50 min zumba, and 5 min cooldown. Polar RS 100 monitors with belts were used to measure the participants’ heart rates. The participants measured their maximal and resting HR by a standardized protocol. ActiGraph GT3X was used to measure the participants’ accelerometer counts, collected in 60-second epochs. The equations by Hiilloskorpi et al. (1999) and Sasaki et al. (2011) were used to determine the participants’ activity energy expenditure from heart rate monitors and accelerometers, respectively. Results The mean vector magnitude counts per minute (cpm) were 8612±1101 cpm and 6704±1424 cpm for interval running and zumba, respectively. The mean working intensity in % of maximal heart rate was 82.5±3.3 % and 74.9±10.7 % for interval running and zumba, respectively. The mean energy expenditure during the running session was 11.51± 2.29 kcal/min and 9.26±1.86 kcal/min estimated by heart rate monitors and accelerometers, respectively (p0.0001). Corresponding energy expenditure for zumba were 9.86± 2.68 kcal/min for heart rate monitors and
7.22± 1.73 kcal/min for accelerometers (p0.0001). Discussion The main finding is the documentation of the large differences in the estimation of energy expenditure between heart rate monitor and accelerometer. Heart rate monitors estimated 24% and 37% higher energy expenditure in kcal/min than accelerometers in interval running and zumba, respectively. A greater difference during zumba could be explained by the fact that the participants perform large upper body movements not recorded by the accelerometer. References Hiilloskorpi H, Fogelholm M, Laukkanen R, Pasanen M, Oja P, Manttari A, Natri A. Factors affecting the relation between heart rate and
energy expenditure during exercise. Int J Sports Med 1999: 20: 438-443. Sasaki JE, John D, Freedson PS. Validation and comparison of ActiGraph activity monitors. J Sci Med Sport 2011: 14: 411-416.
HEART RATE VARIABILITY THRESHOLD PREDICTS LACTATE THRESHOLD IN WORLD-CLASS ROAD CYCLISTSGarcia-Tabar, I., Sánchez-Medina, L., Aramendi, J.F., Ruesta, M., Ibañez, J., Gorostiaga, E.M.
Studies, Research and Sports Medicine Centre, Government of Navarre Introduction The vagal withdrawal of the heart, defined as the heart rate variability threshold (HRVT), and the blood lactate threshold (LT) have been observed to occur at similar relative exercise intensities (Chwalbinska-Moneta et al., 1989; Tulppo et al., 1996). However, the validity of the HRVT to estimate the LT in homogeneous groups of athletes with very high aerobic capacities has not been examined yet.
Methods Twelve male professional world-class road cyclists performed a continuous maximal graded cycling test. Blood lactate concentration ([La-]), heart rate and RR intervals were monitored. The LT was defined as the workload corresponding to an elevation in [La-] of 0.2 mmol•l-1(Weltman et al., 1987). HRVTs were determined from the standard deviation of the instantaneous beat-to-beat RR intervals (SD1).
Workloads associated with SD1 values of 1 ms above the lowest SD1 (SD1Tlow), and 3 ms and 0.5 ms above the SD1 value of the first exercise intensity at which there was a decrease in SD1 0.5 ms (SD1T0.5) or 2.5 ms (SD1T2.5) were established. Results The LT and SD1Tlow were not statistically different and were strongly correlated (r = 0.88; P 0.001). HRVTs robustly correlated with percentages of peak aerobic power (% Wpeak) (r = 0.94-0.97; P 0.001) and percentages of peak heart rate (% HRpeak) (r = 0.87-0.95; P 0.001) at which these thresholds occurred. Discussion A lower magnitude of correlation (r = 0.82) between visually identified LTs and HRVTs has been previously reported in an heterogeneous (coefficient of variation, CV, of ~25%) group of male and female subjects (Karapetian et al., 2008). The present results indicate that the LT could be accurately and objectively estimated from the SD1Tlow in a homogeneous group (CV of Wpeak = 4.3%) of male world-class cyclists. A novel finding was the extremely large relationships observed between the SDlTlow and the % Wpeak and % HRpeak at which SD1Tlow occurred. SD1T0.5 and SD1T2.5, two other mathematically determined HRVTs measurable during a non-fatiguing incremental test, also correlated with the LT, % Wpeak and % HRpeak at which these HRVTs occurred.
Conclusion The LT can be accurately predicted from SD1 values during a maximal or submaximal, non-invasive, low-cost, incremental exercise test in world-class road cyclists. The LT might be coincidental with the vagal withdrawal of the heart. References ChwalbinskaMoneta, J., Robergs, R. A., Costill, D. L., & Fink, W. J. (1989). J Appl Physiol, 66, 2710-2716. Karapetian, G. K., Engels, H. J., & Gretebeck, R. J.
(2008). Int J Sports Med, 29, 652-657. Tulppo, M. P., Mäkikallio, T. H., Takala, T. E., Seppänen, T., & Huikuri, H. V. (1996). Am J Physiol, 271, H244-H252. Weltman, A., Snead, D., Seip, R., Schurrer, R., Levine, S., Rutt, R. (1987). Int J Sports Med, 8, 401-406.
RELATIONSHIP BETWEEN HEART RATE RECOVERY AND LACTATE THRESHOLDS IN ELITE SOCCER PLAYERSBaumgart, C., Hoppe, M.W., Freiwald, J.
University of Wuppertal Introduction In elite soccer players, the ability of the cardiovascular system to recover after high-intensity activities (HRrec) is mentioned as an important prerequisite (Stone & Kilding, 2009). Especially among practitioners, there exist an underlying believe that HRrec is related to aerobic endurance performance factors, such as lactate thresholds. With this in mind, the aim of this study was to investigate the relationships between HRrec and lactate thresholds in elite soccer players. Methods 122 male German soccer players from the 1st to 4th level (age 24±4 years, BMI 23.6±1.6 kg/m2) performed an incremental test on a 400 m tartan track to determine running velocities at 2 and 4 mmol/l blood lactate (v2 and v4). HRrec was defined as the decrease in heart rate from the end of the test to 10, 30 and 60 seconds after exhaustion. Additionally, HRrec was quantified relative as a percent of maximum heart rate (HRrec%). Descriptive statistics were calculated after checking for normality with the Kolmogorov-Smirnov test. Pearson product-moment correlation coefficients (r) were used to investigate the relationship between HRrec, HRrec%, v2, and v4. Statistical significance was set to p.05. Results In elite soccer players,
the assessed mean±SD values for HRrec, HRrec%, v2, and v4 were v2: 12.2±1.2 km/h; v4: 14.2±0.9 km/h; HRrec10: 2±1 bpm; HRrec30:
12±4 bpm; HRrec60: 32±8 bpm; HRrec10%: 1.3±0.8 bpm; HRrec30%: 6.1±2.2 bpm; and HRrec60%: 16.8±4.6 bpm, respectively. No correlations were found between HRrec values, v2, and v4 (all r.13, p.05) as well as between HRrec% values, v2, and v4 (all r.15, p.05).
Discussion The results of this study revealed that v2 and v4 were not related to HRrec and HRrec% in elite soccer players. It is well known that endurance trained athletes have greater HRrec than sedentary individuals. Ostojic, Stojanovic, and Calleja-Gonzalez (2011) demonstrated a relationship between maximum oxygen uptake and HRrec only 10 and 20 seconds after exhaustion in young male soccer players, but not for 30 to 60 seconds. Anyway, the present study shows that elite soccer players possess high aerobic endurance performance factors do not possess faster heart rate recovery after exhaustion. References Ostojic, S. M., Stojanovic, M. D., & CallejaGonzalez, J. (2011). Ultra short-term heart rate recovery after maximal exercise: relations to aerobic power in sportsmen. Chin J Physiol, 54(2), 105-110. Stone, N. M., & Kilding, A. E. (2009). Aerobic conditioning for team sport athletes. [Review]. Sports Med, 39(8), 615-642.
CARDIOVASCULAR EFFECTS OF PASSIVE LOWER LEG VIBRATIONGholoum, M., Edmond, T., Woods, S., Ball, D., Thin, A.G.
Heriot-Watt University Introduction Whole body vibration (WBV) has been used as a novel form of exercise for both physical training and rehabilitation applications. WBV exercise at lower frequencies (60 Hz) for short periods has been reported to have beneficial effects on the human musculoskeletal system (Torvinen et al., 2002). WBV has also been observed to increase muscle blood flow (Kerschan-Schindl et al., 2001). Whether this is a secondary effect in response to skeletal muscle activation or a separate effect on the cardiovascular system is not known.
However, the potential for WBV to produce shear-stress is of interest for its angiogenesis inducing potential. The aim of this study was to investigate the potential vasodilatory effects of vibration independent of muscle activation by applying it in a passive manner. Methods Eighteen (9 male) healthy young adults aged (mean±SD) 22.0±2.3 years, height 1.72±0.09 m, body mass 70.1±13.0 kg were recruited to the study. Skeletal muscle activation was avoided by having subjects lie in a supine position on supporting foam mats with their lower legs resting on the vibrating platform (Nemes, Bosco System). Subjects visited the lab on two separate occasions and vibration and control treatments were applied in a randomised order. Vibration consisted of three 60 s bouts with 10 s between (40 Hz, 3 mm amplitude,
6.8 g RMS acceleration). Lower leg blood flow (LLBF) was measured using venous occlusion plethysmography (Hokanson System). Brachial blood pressure (BP) was measured using an automated monitor (Tango+, SunTech Medical) and ankle systolic BP measured manually in duplicate. Baseline measurements were made following 15 min of supine rest. All measurements were then made immediately after treatment and repeated at 3 min intervals thereafter. Data were analysed using repeated measures mixed model ANOVA. Results Mean
(±SEM) LLBF at baseline was 2.2±0.1 ml/100ml/min. After vibration LLBF was increased relative to the control values by +31.0±7.9, +6.2±5.2, +6.1±6.6, and +9.9±5.2 % at 1, 4, 7, and 10 min respectively (P0.05). Mean ankle-brachial pressure index at baseline was
1.01±0.01 and was reduced by –0.8±2.9, –6.5±3.3, –3.5±3.7, and –0.6±2.1 % at the same respective time points relative to the control values (P0.05). Discussion The results of this study provide evidence for body vibration having cardiovascular effects independent of skeletal muscle activation. This means that WBV may be of use in helping to enhance blood flow during warm-up and/or recovery routines. Furthermore, the most likely mechanism underlying the vibration-induced increase in blood flow is increased shear stress, which may have potential as a novel training stimulus and therefore wants further investigation. References Kerschan-Schindl K, Grampp S, Henk C, Resch H, Preisinger E, Fialka-Moser V, Imhof H. (2001). Clin Physiol, 21(3), 377-82. Torvinen S, Sievanen H, Jarvinen TA, Pasanen M, Kontulainen S, Kannus P. (2002). Int J Sports Med, 23(5), 374-9.