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HIGH INTENSITY EXERCISE HIT IN CHILDREN: RESULTS FROM DIFFERENT DISCIPLINESSPERLICH, B., HAEGELE, M., ACHTZEHN, S., DE MAREES, M., MESTER, J.
GERMAN SPORT UNIVERSITY COLOGNE, THE GERMAN RESEARCH CENTRE OF ELITE SPORT, GERMAN SPORT UNIVERSITY COLOGNE, GERMANYINTRODUCTION: Recent studies of high intensity training (HIT) in different endurance related sports (GIBALA et al. 2007, FAUDE et al. 2008, MacMILLAN 2004) with adult athletes document that HIT leads to similar or even the same physiology adaptations in respectively shorter exercise time compared to high volume training (HVT). Current publications show positive effects on mitochondrial efficiency and lipid metabolism after HIT (DAUSSIN et al 2008). Studies regarding HIT in children are rare. The goal of the study was to compare HIT vs HVT in two different disciplines with different metabolic demands on physiological and performance related parameters in children.
METHOD: Two studies in swimming (A, n= 27, 9-12yrs) and soccer (B, n=19, 14 yrs) were conducted: In both studies the participants were divided into two groups in order to compare the effects of HIT vs HVT. A: Before and after the training intervention maximal oxygen uptake and power output at 4 mmol/L lactate (Lac) were assessed. All participants performed a 2km-test, a 100m test with logging of post lactate kinetics as well as a 6x50m interval-test in a 50m pool. B): Before and after the mesocycle maximal oxygen uptake was assessed. All participants performed a 1km run, as well as a 20m, 30m and 40m sprints. Jumping performance was measured in a drop and counter movement jump. RESULT: A): Training: Workload for HIT was set at ~93% of personal best time corresponding to average lactate values of
5.2±1.2 mmol/l Lactate. HVT was set at 83% of personal best time with average lactate values of 2.3±0.5 mmol/l Lactate. HIT training volume was set at 57x50m, 57x100, 15x200m and 3x300m intervals (total: 27,3 km, time per session:60 minutes). HVT training volume was: 89x100m, 62x200m, 53x300m, 19x400m and 4x800m intervals (57,3km, time per session:90 minutes). No statistical differences were found for any physiological variable between the groups. Competition performance showed an increase of 9% for HVT and 14.3% for HIT.
B): Mean HR during HIT was 25.3% at 90-100% HRmax, 39.3% at 80-90% HRmax, 20.7% at 70-80% HRmax, 11.6% at 60-70% HRmax and 3.2% 60% HRmax. For HVT HR was set at 0.8% at 90-100%, 27.0% at 80-90% HRmax, 42.5% at70-80 HRmax, 9.7% at 60-70 HRmax and 9.9% below 60% HRmax. Mean Lac-values in HIT were 8.74±3.20mmol/L Lac and 2.17±1.09mmol/l. Oxygen uptake increased depending on recovery time.
Summary: The results indicate that HVT is not necessarily beneficial as trainings strategy compared to HIT in swimming and soccer at the age of 9-14 years.
In the presented studies, HIT showed similar effects compared to HVT achieved in less training time. The data also reveals performance enhancing effects depending on time of recovery. This saving in time may favor training contents such as technical and strength drills as well as recovery in the long term development of performance.
14:00 - 15:30 Oral presentations OP-PH05 Physiology 5
POST-RESISTANCE EXERCISE HEMODYNAMICS IN ELDERLYQUEIROZ, A.C.C., KANEGUSUKU, H., CHEHUEN, M.R., COSTA, L.A.R., WALLERSTEIN, L.F., MELLO, M.T., UGRINOWITSCH, C., FORJAZ, C.L.M.
UNIVERSITY OF SAO PAULO - FEDERAL UNIVERSITY OF SAO PAULO
Methods: Sixteen normotensive elderly (63±1 years; 123±2/79±1 mmHg), who were already participating in a strength training program for 12 weeks, underwent two experimental sessions in a random order: Control (C) – remain seated for 90 min, and Exercise (E) – 7 resistance exercises (3 sets of 8 RM). Auscultatory BP, cardiac output (CO-CO2 rebreathing) and heart rate (HR-ECG) were measured before and at 30 and 60 minutes after interventions. The responses (difference between values measured post and pre interventions: Δ30pre and Δ60-pre) were compared by a 2-way analysis of variance for repeated measures. Data are presented as means±SE.
Results: Systolic and mean BP increased in the C (greatest increases = +8.4±1.4 and +4.4±0.9 mmHg, P0.05, respectively), and did not change in the E session. Diastolic BP did not change after both sessions. Systemic vascular resistance increased similarly in both sessions, while CO decreased significantly only in the E (greatest decrease = -0.5±0.1 l/min, P0.05). Stroke volume decreased, while HR increased significantly in the E session (greatest responses = -9.6±1.9 ml/beat and +3.7±1.5 beat/min, P0.05, respectively).
Conclusion: In trained elderly, each session of resistance training promoted post-exercise hypotensive effects, since BP increased after the C session, which was prevented by the E session. This effect was due to a CO decrease that is not compensated by an increase in systemic vascular resistance. CO reduction after resistance exercise was mediated by a stroke volume decrease that was not compensated besides the HR increase.
Financial support: FAPESP and CNPQ.
CHANGES IN MUSCULAR STRENGTH: FROM BIRTH TO DEATHSEENE, T., KAASIK, P., PUHKE, R., SEENE, M.
UNIVERSITY OF TARTUIntroduction: It is well known that there are gradual, progressive and regressive changes in body structure and function from birth to death. These progressive changes are rapid during the intensive growth period but slow down from the fourth decade of life, particularly
14 ANNUAL CONGRESS OF THE EUROPEAN COLLEGE OF SPORT SCIENCETH Wednesday, June 24th, 2009 skeletal muscle mass and strength (Herndon et al., 2002). Protein synthesis in skeletal muscle, particularly contractile protein myosin heavy chain (MyHC), has been found to be a predictor of locomotory function. A reduction of contractile proteins contributes to the decline muscular strength (Seene et al., 2008). The purpose of the present study was to assess changes in muscle strength from one month to 80 years old age, and find the relations with changes in locomotory function through the life-span.
Methods : Under assessment were persons from one month till 80 years of age. Pediatric assessment techniques were used for physical examination during the preschool period. Arm and leg strength (1RM), muscle fiber types, cross-section area, myonuclear domain size and the myosin heavy chain isoform pattern were measured as described earlier (Seene et al., 2008).
Results: Strength development starts at birth in the form of movements in gravitational field. Taking into account that a infant’s head is 2/3 of its total mature size and muscle mass comprises about 20% of the total bwt, these movements have to exert a force of attraction. After the fourth decade of life, muscle strength slowly begins to decline. Between 30 and 40 years of age, the decline was ~5%, 40 and 50 ~14%, 50 and 60 ~16%, 60 and 70 ~26%, and 70 and 80 ~30%. The decrease of muscle strength is accompanied with the decrease of FT muscle fibers and IIx isoform relative content of MyHC.
Discussion: It is a widely accepted standpoint that the best time for strength development starts from late puberty. In reality, a newborn infant starts to fight with gravitation at birth and this process is actual strength development. The development of posture control across the life-span and its integration with locomotory function show dependence on the muscle strength. When balancing, older adults as well as like young children, use antagonist muscles more often in coactivation with agonist muscles (Woollacott et al., 1986). Muscle weakness is the main factor in the dysfunction of locomotor acitvity and balance through the life-span. A decline in muscle strength is in good agreement with the decrease of proportion of FT muscle fibers and IIx MyHC isoforms relative content in skeletal muscle. Locomotory dysfunction in infants and elderly people is the result of insufficient muscle strength.
References Henderson L, Schmeissner P, Dudaronek J, et al. (2002). Nature, 419, 808-814. Seene T, Umnova M, Kaasik P, et al. (2008). Skeletal Muscle Damage and Repair, 173-184. Human Kinetics.
Seene T, Kaasik P, Alev K, et al. (2008). 6th Int Conf on Strength Training, 41-42. NSCA.
Woollacott M, Shumway-Cook A, Nashner L (1986). Int Aging Hum Dev, 23, 97-114.