Duration of exercise and anaerobic energy share. Assesment of anaerobic capabilities in elite athletes. Evaluation of anaerobic capabilities

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1 Assesment of anaerobic capabilities in elite athletes Dušan Hamar Dept. of Sports Medicine Inst. of Sports Sciences Bratislava Slovakia Energy share (%) Duration of exercise and anaerobic energy share Exercise duration aerobic anaerobic (Bangsbo, et. al. 199) March May 3 6 Power (W) March Time(s) May Work (kj) ,8 Mach 49 May VO2 (l/min) Time (s) VO2 (l/min) ,31 3,42 March May Lactate (mmol/l) ,1 March 9,4 May Evaluation of anaerobic capabilities Oxygen debt Oxygen debt Problem with setting the baseline oxygen uptake Blood lactate after all-out exercise Mechanical power Unreliable! 1

2 Blood lactate after all-out exercise Mechanical Power Problems wash-out, compartment distribution, elimination complicate indirect assessment of energy produced in anaerobic pathways Individual differences in oxygen uptake kinetics alone does not provide any clue on efficiency of mechanical work performed Unreliable! A P = t F x s P = t P = F x v A = F x s s v = t An All-out Exercise on the Cycle Ergometer Widely used means for the assessment of anaerobic capabilities Wingate Anaerobic Test Resistance: 7.5 N/kg of BW Power = Force x Velocity (Velocity = Revolution Rate x 2 x 3.14 x Crank Length) Classic Wingate test - constant braking force 15 Pmax 12 2 Pmean 16 Isokinetic cycle ergometer 9 Pmin Pmax-Pmin Fatigue index = Pmax ČAS (s) 8 4 Tensometer Brake Revolution rate sensor 2

3 All-out Bouts on an Isokinetic Cycle Ergometer Force and power at different revolution rates 1-second all out pedalling Mean throughout the cycle: 539 N Mean throughout the cycle: 389 W Force and power at various revolution rates Force (N) Optimum revolution rate Pmax Power (W) POWER ST FTO FTG Revolution rate (1/min) VELOCITY 3

4 FORCE (N) 2 15 Force-velocity and power-velocity curves of different groups of cyclists 2 UNTRAINED ROAD CYCLISTS TRACK CYCLISTS 15 FORCE (N) 2 15 Specific effect of training in track cyclists 2 JAN MAR APR REVOLUTION RATE (1/m) Force and power at various revolution rates Force (N) Optimum revolution rate Revolution rate (1/min) Pmax Power (W) Classic Wingate test - constant braking force ČAS (s) CADENCE (rpm) Wingate test in isokinetic mode at 1 rpm CAS (s) CADENCE (rpm) isokinetic Mode constant force TIME (s) 4

5 CONSTANT FORCE MODE ISOKINETIC ČAS (s) Parameters of Wingate test performed in different modes POWER (w) constant force isokinetic MODE maximum minimum mean 3-second all out workloads at 4, 6, 8, 1 a 12 rpm. POWER (w) Fatigue and optimum revolution rate s 25-3 s Theoretic optimum time course of revolution rate to achieve highest possible power in 3- second all out test POWER FTO FTG ST VELOCITY TIME (s) 5

6 after rehabilitation before rehabilitation 6

7 An All-out Exercise on the Cycle Ergometer For many sports cycling is not a specific form of exercise VELOCITY (km/h) Constant Power All-Out Exercise RUNNING at 22 km/h, 7.5 % slope TIME (s) Time to exhaustion: 65.1 s Tethered running on the treadmill Anaerobic power and specificity of the test exercise? FORCE (F) VELOCITY (v) Energy demand of running itself + Power produced due to pulling work at given velocity P = F x v POWER (w) REVOLUTION RATE (RPM) Fit subjects Cyclists Sprinters POWER (w) VELOCITY (km/h) Maximal Power In Different Forms Of Exercise Maximal 5-second drag power at different velocity of tethered running POWER (w) FIT SUBJECTS CYCLISTS SPRINTERS CYCLE ERGOMETER TETHERED RUNNING Power (w) Velocity (km/h) 7

8 Maximal 5-second drag power at different velocity of tethered running Power (w) Velocity (km/h) Sprinter Endurance runner Power and velocity of contraction in muscles with predominace of ST and FT fibers 8, gastrocnemius 6, 4, 2, soleus, Power (W) Velocity (cm/s) Edgerton, 1989 more than 5 % FT fibers Maximal 5-second drag power at different velocity of tethered running VÝKON (w) less than 5 % FT fibers Tihanyi, RÝCHLOSŤ (km/h) 3-s All-Out Tethered Running at 18 km/h - Averaged Data Over 5-s Periods TIME (s) 8

9 Drag Power Produced In 3-s Test Of Tethered Running On The Treadmill A Pmax: 636 W Pmean: 525 W FI: 4 % TIME (s) B Pmax: 49 W Pmean: 381 W FI: 15 % 9

10 Assessment of explosive power of lower extremities Principles of parameter estimation from force-time curve Dynamometric platform Contact platform F = (m x g) + (m x a) F = m x (g + a) F a = - g m v= integral a (a. t) h = integral v (v. t) P = F x v Principles of parameter estimation on contact platform Formulae for calculations of basic parameters Measurement of flight and contact times during serial jumps Calculation of Height of the jump Power in concentric phase of take off Height of the jump g. Tf 2 h = Power in concentric phase of take off g 2. Tf. ( Tc +. Tf) Pact = Tf h (m) Tf (s) Tc (s) Pact (W.kg -1 ) g 9.81 m.s -2 Screen during on line measurement Pact in groups of athletes 1

11 Pact before and after specific training Efect of counter movement on height of the jump in two subjetcs Height of the jump (cm) A B without CM with CM Height of the jump without and with additional weight (5 % of body weight) 11