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University of Hull Introduction Maximal oxygen uptake (VO2max) is considered to be the criterion measure of cardiorespiratory fitness (ACSM, 2010). A nonmotorised treadmill (NMT) may better simulate the physical stress of the training environment and/or be better suited for testing team sport players. However it is unknown if the NMT allows the exerciser to reach VO2max. The aim of the study was to examine the physiological responses to VO2max test protocols on motorised and non-motorised treadmills. Method Sixteen males completed one continuous incremental test to exhaustion on a motorised treadmill (Cosmos) and two incremental tests on an NMT (Woodway Force 3) in a randomised order. Participants completed the motorised treadmill test using a step protocol that increased by 1 km.h-1.min-1 at a gradient of 1% (MOT-CONT). The first NMT trial mirrored the motorised treadmill protocol (NMT-CONT) with the second NMT trial using an intermittent step protocol also increasing by 1 km.h-1.min-1, but alternating between higher and lower speeds (2 x 15 s blocks per minute NMT-15). Heart rate was measured in the final 15 s of each stage. Expired air was measured by a breath-by-breath system (Oxycon).
Data were analysed using the effect size statistic and 90% confidence intervals (Hopkins, 2009). Results The mean (SD) VO2max (mL.kgmin-1) were MOT-CONT 46 (7), NMT-CONT 46 (7), NMT-15 45 (7). The mean difference as an effect size for MOT-CONT vs. NMT-CONT (ES = -0.03; 90%CI -0.12 to 0.09) and MOT-CONT vs. NMT-15 (ES = -0.16; 90%CI -0.37 to 0.05) were both trivial. The mean (SD) peak speeds (km.h-1) were MOT-CONT 15.1 (1.5), NMT-CONT 10.3 (0.9), NMT-15 13.8 (1.0). The mean difference in peak speed as an effect size for MOTCONT vs. NMT-CONT was very large (ES = -3.71; 90%CI -4.13 to -3.29). The mean difference in peak speed as an effect size for MOT-CONT vs. NMT-15 was moderate (ES = -0.87; 90%CI -1.35 to -0.38). The mean (SD) HRpeak (beats.min-1) were MOT-CONT 186 (7), NMT-CONT 178 (9), NMT-15 183 (7). The mean difference as an effect size for MOT-CONT vs. NMT-CONT was large (ES = -0.84; 90%CI -1.10 to -0.59) and for MOT-CONT vs. NMT-15 was small (ES = -0.38; 90%CI -0.63 to -0.13). Discussion VO2max can be successfully achieved on an NMT when using the same protocol as used on a motorised treadmill. However, the peak speed achieved is reduced by approximately one third and with a large reduction in HRpeak. When an incremental protocol is performed intermittently on the NMT the same VO2max can be achieved together with smaller reductions in peak speed and HRpeak compared to a motorised treadmill protocol. References Thompson (2010). ACSM’s Guidelines for Exercise Testing and Prescription (9th Edn). Hopkins (2009). MSSE, 41(1), 3–13.
AN INNOVATIVE PROCEDURE FOR THE ANALYSIS OF V’O2 KINETICS WITHOUT DATA PRE-TREATMENTBringard, A.
University of Geneva Introduction The study of pulmonary gas exchange dynamics at the onset of exercise is constrained by the low time resolution due to breathing frequency and the low signal-to-noise ratio. Off-line interpolation was proposed to artificially increase the time resolution, but it may induce data distortion. The aim of this study was to propose and evaluate a new approach to the problem of poor time resolution in the analysis of breath-by-breath V’O2 kinetics. Methods A set of noiseless bi-exponential VO2 kinetics (Barstow and Molé, 1987), mimicking transitions from rest to moderate exercise, were simulated by Monte-Carlo method. This provided a set of exact data, which we used as reference data. The parameters were randomly selected from intervals that cover the range of physiological values for this intensity domain. Then, each of these kinetics was sampled 10 times with non-uniform sampling time, mimicking breathing patterns during restexercise transition, and was subjected to 3 different pre-treatment procedures. The linear (Hughson et al, 1993) and step (Lamarra et al,
1987) pre-treatment methods consisted, respectively, of linear and step 1-s interpolations of each repetition. Then the average value was calculated for each second, resulting in an “averaged transition”, to which bi-exponential fitting was applied. Our method (called none) needed no interpolation: the data of the 10 repetitions were pooled together as if they were from the same transition. Bi-exponential fitting was applied to the pooled data. For all methods, data were compared with the exact values. The confidence intervals were estimated by bootstrap using the bias corrected and accelerated percentile method. Results Phase I time constant (τ1) data lying exactly on the identity line were more numerous with the none than with the linear and the step methods. With the none method, the identity line stayed within the confidence intervals for τ1 but was below the lower confidence interval curve for the step and the linear methods, indicating that both overestimated τ1. Discussion The better performance of the none method is due to the fact that the linear and step methods introduce a “filter-like” effect (interpolation followed by data averaging) that affect the data. This kind of pre-treatment is not present in the none method. By definition, a filter affects the time constants of an exponential response. We conclude that the none method should be used instead of the linear and step methods, when the rapid phase of V’O2 kinetics is to be analysed. References Barstow TJ, Molé PA. (1987). J Appl Physiol, 63, 2253–2261. Hughson RL, Cochrane JE, Butler GC. (1993). J Appl Physiol, 75, 1962-1967. Lamarra N, Whipp BJ, Ward SA, Wasserman K. (1987). J Appl Physiol, 62, 2003-2012.
14:00 - 15:00 Mini-Orals PP-PM47 Physiology [PH] 14
PHYSIOLOGICAL ADAPTATIONS OF AN 8-WEEK RECREATIONAL SOCCER PRACTICE AND RUNNING TRAINING IN UNTRAINED WOMENOrtiz, J.G., Fernandes da Silva, J., Guglielmo, L.G.A., Diefenthaeler, F.
Universidade Federal de Santa Catarina PHYSIOLOGICAL ADAPTATIONS OF AN 8-WEEK RECREATIONAL SOCCER PRACTICE AND RUNNING TRAINING IN UNTRAINED WOMEN Introduction Soccer is a potential element to induce physiological adaptations and improved performance for all types of people (Randers et al., 2010). Physiological indices are references to identify the effects of training in many sports (Impellizeri et al., 2006). Thus, the purpose of the present study was to compare physiological adaptations of an 8-week recreational soccer practice and running training in untrained women. Methods Twenty-six untrained women were separated in two groups: soccer (SG) and running group (RG). Participants performed three times per week training during eight weeks. The soccer sessions consisted of ordinary eight-a-side matches on a 50 x 30 m artificial grass field. The aerobic training sessions consisted of continuous and interval training at low intensity and high intensity running on a motorized treadmill. Maximal incremental running test to determine maximum oxygen uptake (VO2max), lactate threshold (LT) and onset of blood lactate accumulation (OBLA) was performed before and after the intervention period. Data were evaluated by twoway analysis of variance on repeated measurement (p0.05). Effect size (ES) was calculated, in which values of 0.2, 0.5 and 0.8 were considered small, moderate and large, respectively. Results After eight weeks of training VO2max increased from 37.0±6.4 to 41.4±6.0 ml.kg-1.min-1 in SG (p0.05; ES:0.7) and from 36.5±6.2 to 42.2±5.5 ml.kg-1.min-1 in RG (p0.05; ES: 1.0); speed at LT increased from
6.1±0.7 to 6.7±0.9 km.h-1 in SG (p0.01; ES:0.8) and 6.0±08 to 7.0±1.2 km.h-1 in RG (p0.01; ES:0.8); speed at OBLA increased from 7.2±1.1 to 8.1±1.5 in SG (p0.01; ES:0.6) and 7.1±1.1 to 8.4±1.1 km.h-1 in RG (p0.01; ES:1.2). Discussion The main novel finding of the present study is that soccer training lead similar improvements to aerobic training performed at LT and OBLA intensities, generating significant changes in the metabolic and aerobic capacity. These results are in agreement with previous studies that investigated both indices (McMillan et al.
2005; Impellizzeri et al. 2006). Moreover, the improvement in VO2max (11 and 14% in SG and RG, respectively) is in agreement with a similar study, in which improved 15 and 10% in SG and RG, respectively (Bangsbo et al., 2010). Thus, the intensity of training conducted during physical exercise is key aspect for improvement of physiological indices. References Bangsbo J, Nielsen J, Mohr M, et al. (2010).
Scand J Med Sci Sports, 20, 24-30. Impellizzeri FM, Marcora SM, Castagna C, et al. (2006), Int J Sports Med, 27, 483-492. McMillan K, Helgerud J, Grant SJ, et al. (2005), Br J Sports Med 39, 432-436. Randers MB, Nybo L, Petersen J, et al. (2010). Scand J Med Sci Sports, 20, 14-23.
LACTATE TURN POINTS, CRITICAL LACTATE CLEARANCE AND CONSTANT LOAD CYCLE ERGOMETER EXERCISEHofmann, P.1, Mueller, A.1, Tschakert, G.1, Groeschl, W.1, Wallner, D.2, Burgsteiner, H.2 1: University of Graz 2: University of Applied Science Graz, Austria Introduction According to the lactate shuttle theory (Brooks 2002), two turn points (LTPs) and three phases of lactate metabolism may be detected during incremental (Hofmann and Tschakert 2011) and constant load exercise. Aim of our study was to validate LTPs by constant load ergometer exercise (CE) below and above the pre-determined LTPs in a heterogenous group of subjects. Methods 23 healthy male and female subjects (age: 36.0±13.2 yrs; body mass: 67.4±9.0 kg; VO2max: 49.5±9.7 ml.kg-1.min-1) performed maximal cycle ergometer exercise (IE) (20/40W start; 15/20W.min-1 increments). The first (LTP1) and the second (LTP2) lactate turn points were determined by linear regression break point analysis. CE tests (30 min) were performed at 5% (or 10%) Pmax below and above LTP1 and LTP2 in all subjects.
Heart rate (HR) and gas exchange variables were determined and blood lactate concentration (La) was determined at rest, at the end of every workload step (IE), every 5 min in CE as well as during 3 and 6 min of active and passive recovery. Results: Power output in IE was
261.0±59.8 W at Pmax, 179.9±46.1 W at LTP2 (68.9±3.2 % Pmax) and 89.7±32.0 W at LTP1 (34.4±6.8 %Pmax). Subjects worked at
76.8±29.4 W (LTP1-), 102.9±34.6 W (LTP1+), 162.6±41.1 W (LTP2-) and 184.0±44.8 W (LTP2+) which were 28.7±6.6 %Pmax (LTP1-), 38.7±6.6 %Pmax (LTP1+), 62.1±3.5 %Pmax (LTP2-) and 70.5±5.0 %Pmax (LTP2+) as well as 39.9±7,9 %VO2max (LTP1-), 49.3±7.0 % VO2max (LTP1+),
76.4±5.6 % VO2max (LTP2-) and 88.0±6.9 % VO2max (LTP2+), respectively. La was 12.44±2.25 mmol.l-1 (max), 3.58±0.71 mmol.l-1 (LTP2)
and 1.21±0.41 mmol.l-1 (LTP1). Subjects completed 30 min of CE up to LTP2- and stopped earlier with increasing work load (LTP2+:
22.0±7.8 min). Mean La values were sign. Different during CE at 0.83±0.02 (LTP1-), 1.21±0.04 (LTP1+), 4.96±0.09 (LTP2-), and 7.54±.0.07 (LTP2+). 16 of 23 subjects presented a lactate steady state at 5% below LTP2 and 7 subjects showed a steady state at 10% below LTP2.
Discussion According to the lactate shuttle theory (Brooks 2002), two distinct turn points and three phases of lactate metabolism, detected during IE (Hofmann and Tschakert 2011) were also found for CE. LTPs distinguished the lactate curve into different metabolic domains, were significantly related to the CE lactate response and define and discriminate the main metabolic trainings zones “low”, “moderate” and “vigorous” for constant load exercise training. References Brooks GA (2002). Biochemical Society Transactions (2002) 30, 2: 258-264.
Hofmann P, Tschakert G (2011). Cardiology Research and Practice, ID 209302, 10 pages, doi:10.4061/2011/209302. The project was funded by the Austrian Research Promotion Agency, project n. 827572.
IS THERE A RELATION BETWEEN CHANGES IN TRAINING PERFORMANCE AND AEROBIC OR ANAEROBIC CAPACITY
DURING TWO-WEEK HIGH-INTENSITY INTERVAL TRAINING?Koivumäki, M.1, Hannukainen, J.1, Eskelinen, J.J.1, Savolainen, A.1, Heinonen, I.1, Virtanen, K.1, Kemppainen, J.1, Kapanen, J.2, Knuuti, J.1, Kalliokoski, K.K.1 University of Turku, Turku, Finland, Introduction High-intensity interval training is a time-efficient strategy for promotion of health by physical exercise (Gibala et al. 2012). We investigated whether the changes in training intensity between the six training sessions over the period of two weeks of high-intensity interval training (HIT, Wingate protocol) are related into the changes in aerobic fitness (VO2max) and anaerobic capacity (blood lactate).
Methods 13 healthy sedentary middle-aged men (age 48 ± 5 years and BMI 25.8 ± 2.9) trained six HIT sessions within two weeks using Monark 894 E ergometer. A session consisted of 4 -6 x 30 s maximal sprints (Wingate protocol) with 4 min rest between the sprints. The amount of training was increased after every second session (4-5-6 sprints). The Monark anaerobic test software 3.0.1 with the ergometer provided detailed information of the different parameters related to training intensity during the sprints and we selected peak (PEAK) and average (AVG) power and power drop (DROP) to be the most representative parameters of the training load. As the amount of sprints differed, we took only the first four sprints from every session for the analysis. The subjects did also VO2max test (cycle ergometry, start intensity 50 W, increased 30 W every two minutes until to the volitional fatigue) before and after the training. One subject abandoned the study due to personal reasons. Results VO2max improved by 6.2 % (from 34.0 ± 3.7 to 36.2 ± 4.5 ml/kg/min p=0.005) and blood lactate 28.6% (from 10.8 ± 1.7 to 13.8 ± 2.7 mmol/l p0.001) after the training. Average power in the sprints increased during the training period and this was especially due to increase in power in the third and fourth sprint (about 10%). Power drop in the sprints decreased during the training intervention (from about 58 at the first training session to 51 % at the last training session, p0.05). Peak power remained unchanged. We found no correlation between the changes in the training data with VO2max or blood lactate improvements.