Paul Thawley MSc Neuromuscular Adaptation Is this predominately what Physio`s do ?

1. Paul Thawley MScNeuromuscular AdaptationIs this predominately what Physio`s do ?

2. Basic definitions • Strength • Maximal amount of force a muscle or a muscle group can generate • Power • The rate of performing work • F x V

3. Mechanisms influencing muscle strength Mechanical Structural Neural • Muscle Mechanics • Pre-stretch effect • Hypertrophy • Vascularization • MHC change • Conn. Tissue • Recruitment • Synchronization • Inter-Musc • Coordination • Intra-Musc. • Coordination

4. Time-course of adaptations Progress Strength Hypertrophy Neural adaptations Time (Modified from Sale, 1988)

5. High level brain controller Specific Adaptations T R A I N I N G Motor Cortex Spinal Cord Sensory receptors Specific MU activation Force Output Muscle

6. Force generation and fiber recruitment

7. Specificity • Increase in maximal isometric force (e.g. Kitai & Sale, 1989; Rutherford & Jones, 1988) • The improvements are in the range of 18% of the range of motion used for training (Kitai & Sale, 1989) • Dynamic training is superior to static training if the outcome is dynamic performance High Force 0 Velocity F V

8. Mechanics Specificity Concentric training has been shown to be effective in improving dynamic muscle performance (e.g. Johnson 1972; Komi & Burskirk, 1972) Eccentric training has been shown to be effective in improving dynamic performance (e.g. Komi & Burskirk, 1972)

9. Specificity % increase weeks From Rutherford & Jones (1986)

10. Hypertrophy Size of muscle fiber weeks

11. What is hypertrophy • Increase in muscle cross-sectional area • This increase has been attributed to an increased size and number of actin and myosin filaments and to additions of sarcomeres within existing muscle fibers (Mac Dougall et al., 1979; Goldspink, 1992) • Not all muscle fibers undergo the same amount of enlargement

12. Hypertrophy The hypertrophic response depends on the stress applied to the muscle structure New sarcomeres are formed nearby the damaged muscle cell. This is regulated by post-transcriptional events

13. An example Before 2 Days after 7 Days after 1 x 10 2 x 10 From Hortobagyi et al. (1998) JAP

14. Hyperplasia • Increase in the amount of muscle fibers • It has been demonstrated in animal-based studies • Contradictory evidence in humans

15. Stretch as an hypertrophic signal (McComas,1994) Stretch Release of soluble factors from muscle fiber or extracellular matrix Activation of second messenger system in fibers Induction of immediate early genes Transcription of muscle genes Muscle fiber hypertrophy Prostlaglandins ? Arachidonic Ac Phospholipase Protein kinase c Tyrosine kinase

16. Hawke and Garry, JAP (2001)

17. Effective exercise approach • Eccentric training is effective in determining hypertrophic responses • Stretching of muscle fibers affect gene transcription • Eccentric mechanical work determine release of prostaglandines • Prost. affect immediate early-genes controlling transcription of other genes in the nucleus of muscle cells • Specific adaptations occur in the muscle cell

18. Pain after exercise • Eccentric contractions may cause muscle discomfort and/or pain • It appears usually the following day and can last for more days • This phenomen is referred to as “Delayed Onset of Muscle Soreness” • This is due to damage to the muscle fibers causing edema, swelling and inflammatory responses in the muscle cell

19. Muscle damage

20. Detraining From Hakkinen & Komi (1985) Heavy resistance training Detraining % C H A N G E weeks

21. Aging 30 Years old F 50 Years old 70 Years old Time

22. Hormonal adaptations during exercise • Regulation of growth • Reg. Development • Reproduction • Capability of handling physiological stress • Capability of handling psychological stress

23. Effects of exercise on human body • Exercise represents a strong stress applied to human biological structure • This added stress generates physiological responses aimed to re-establish the metabolic processes

24. Resistance exercise and specific hormones (T) • In adult men, acute increases following resistance exercise are observed following adequate stimulus ( multiple sets, 5-10 RM, adequate muscle mass) • A study by Hakkinen et al. (1988) conducted on professional weighlifters over 2 years time showed increase in T, FSH, LH. • Relatively small variations have been found in women. • Long rest periods are related to an increase in T production

25. Manipulating the Endocrine system naturally with resistance training • The more muscle fibers rectuited for an exercise, the greater the extent of potential remodeling • Only muscle fibers activated by the resistance training are subject to adaptation, including hormonal adaptation to stress • To increase Serum Testosterone • Use large muscle-group exercises • Use Heavy resistance exercise (85% to 95% of exercise) • Use moderate to high volume of exercise • Use 60 to 90s intervals • To increase Growth Hormone • Use workouts with higher lactate concentrations and high intensity (> 10 RM) with 3 sets of each exercise and short rest periods • Supplement diet with carbohydrate and protein before and after workout

26. Overtraining and Overreaching • OVERREACHING: An accumulation of training and non-training stress resulting in a short-term decrement in performance capacity • OVERTRAINING: An accumulation of training and non-training stress resulting in long term decrement in performance capacity

27. The main principle Stimulus Fatigue Recovery Super- compensat Decrease

28. Steps to build the program • Resistance training goal • Exercise selection • Exercise Order • Training load and repetitions • Volume • Rest Periods

29. Resistance training goals • Hypertrophy ? • Maximal strength ? • Power ? • Movement specific strength ? • Mainteinance of strength

30. Exercise selection Core exercises Large muscle areas and multijoint Assistance exercises Small muscle areas and single joint Structural exercises Load on the spine Power exercises Weight quickly lifted

31. When deciding the exercise • Consider Exercise technique experience • Equipment availability • Training time availability • Muscle Balance • Sport-Specific technique • Previous injuries of the individual

32. Exercise Order • Power, Core and Assistance • Stress on power enhancement • Upper and Lower body (Alternated) • For non- well trained individuals • Push – Pull • Indicated for circuit training • Supersets and Compound sets • Two exercise with opposing muscles • Two exercise for same muscle group

33. Assign the training load Determine 1RM Or Build F/V rel. Decide number of repetitions Establish goal (Hypertrophy, Power?) Decide volume Sets x Reps Chose % of 1RM Or load on F/V curve

34. For gaining Strength/power • The weight has to be lifted as fast as possible • Use load assignment to increase maximal strength and optimise power production • Every repetition should be performed at more than 90% of the maximum power • In this way FT fibers are recruited

35. For gaining hypertrophy • Use heavy loads • Use multiple sets • Use repetitions to fatigue • Use eccentric type of training • Reduce rest between sets • Recruit all muscle fibers

40. Adaptations to Exercise Training Each person responds differently to each training program.There is a psychological component to training.The magnitude of the physiological or performance gain is related to the size of an athlete’s adaptational windowThe amount of physiological adaptation depends on the effectiveness of the exercise prescriptions used in the training program.Training for peak athletic performance is different from training for optimal health and fitness.

41. Neural Adaptations • Increases in strength due to short term Increases in strength due to short term (eight to twenty weeks) training are the (eight to twenty weeks) training are the result of neural adaptations. result of neural adaptations. • Neural adaptations can include improved Neural adaptations can include improved synchronization of motor unit firing and synchronization of motor unit firing.

42. Neuromuscular Adaptions • Specificity It is important to know that neuromuscular adaptations are closely related to the specific exercises. • ExercisesExercise prescription If you select a small number initially. • High number of setsWhen you were 4 years old and tried to ride your bike for the very first time, you did not try only once to master the discipline. You tried over and over again • High number of Reps • Load 60% 1RM or 10RM

43. How? • Decide which mm group • Decide which exercise • Decide how much volume Eg Hypertrophy 70% of max = MU Patterning below 50% of max = MU Proprioception

44. Eg 120 reps @ 40% • Eg 60 reps @ 70% Low force Low MU High force High MU High patterning Low paterning

45. How Do I set Load Objective Strain gauge: work out % Subjective Lift weight 10 times = 70% 1RM. If pt lifts Wt 20 reps below 50% 1RM Most MU used in Ecc ? ACL rehab early very functional Pattern Isometric Isotonic Eccentric

46. Important that Proprioception is linked to all stages of Rehab! • ACL 6 wks post op MM atrophy Quads / Hamstrings Hamstrings to Quads ratio Speed of contraction Main mm function of MM groups involved