Muscular Strength and Endurance Lecture Notes PDF

KIN 2210: Advanced Exercise Prescription Muscular Strength and Endurance Required Reading Course Notes Campos et al, 2002  Agenda Physiological Basis of Muscular Strength and Endurance Adaptations to Training Training Methods Program Design P...

KIN 2210: Advanced Exercise Prescription Muscular Strength and Endurance Required Reading Course Notes Campos et al, 2002  Agenda Physiological Basis of Muscular Strength and Endurance Adaptations to Training Training Methods Program Design Physiological Basis of Muscular Strength and Endurance  Neuromuscular System Nervous System Muscular System Function of Neuromuscular System 1. Brain generates signal 2. Signal delivered to muscle through motor neurons 3. Muscle contracts in response to signal Generation of the Action Potential 1. Generated in Motor Cortex 2. When decision to move is made, AP is created 3. Muscle contract in response to AP 4. Muscle relax in the absence of AP Motor Neurons Upper Motor Neurons Originate in the Motor Cortex Axon travels down Spinal Cord Innervates Lower Motor Neurons Lower Motor Neurons (⍺-MN) Originate in the Spinal Cord Axon travels peripherally Innervates muscles Neuromuscular Junction 1. MN release Acetylcholine at NMJ 2. Ach travels across the synaptic cleft and binds to its receptor 3. New AP is generated Muscle Contraction and Ca 2+ Release 1. AP travels along sarcolemma 2. AP travels down T-Tubule 3. AP triggers Ca2+ release from SR 4. Ca2+ binds to troponin, shifting tropomyosin off actin binding sites  T-Tubule Muscle Contraction and Ca Release 2+ Ca2+ 3. AP triggers release from SR 4. Ca2+ binds to troponin, shifting tropomyosin off actin binding sites 5. Myosin binds to Actin and performs Power Stroke 6. Muscle contracts and produces tension Muscle Relaxation and Ca 2+ Reuptake 1. When AP stop, Ca2+ is actively pumped back into the SR 2. Tn and Tm return to resting positions Muscle Relaxation and Ca Reuptake 1. 2+ When AP stop, Ca2+ is actively pumped back into the SR 2. Tn and Tm return to resting positions 3. Myosin-actin binding sites are blocked 4. Muscle relaxes, and returns to resting length Motor unit α-MN and all the muscle fibers it innervates Every muscle fiber is innervated by a branch of a ⍺- MN All-or-None Response Arrangement of Muscle Units Fibers of different MUs overlap Motor Unit Types Muscle fibers within a given motor unit, have the same biochemical and physiological properties Regulation of Force Production  Motor Unit Recruitment The number of motor units activated to perform the task Recruitment order maintained for all Recruitment contractions types Threshold Slow MU recruited for all contractions FF MU recruited infrequently Motor Unit Recruitment  Rate Coding The rate at which APs are conducted to the individual motor units Tetnus Twitch Summation Single Twitch Force-Frequency Relationship Force (% Max) Hirschfield et al, 2000 Physiological Adaptations to Strength Training  Muscular Strength The maximum amount of force that a muscle can exert against a resistance in a single effort  Performance What training principle is being illustrated? Weight of lifts increased throughout training period Trezise J and Blazevich AJ (2019) Anatomical and Neuromuscular Determinants of Strength Change in Previously Untrained Men Following Heavy Strength Training. Front. Physiol. 10:1001.  Recruitment Recruited more of the muscle after training period Trezise J and Blazevich AJ (2019) Anatomical and Neuromuscular Determinants of Strength Change in Previously Untrained Men Following Heavy Strength Training. Front. Physiol. 10:1001.  Rate Coding Frequency of APs increased after training period Del Vecchio et al. (2019) The increase in muscle force after 4 weeks of strength training is mediated by adaptations in motor unit recruitment and rate coding. J Physiol. 597(7):1873-1887  Cross-sectional Area Small Cross-Sectional Area Large Cross-Sectional Area CSA of muscle increased after training period Trezise J and Blazevich AJ (2019) Anatomical and Neuromuscular Determinants of Strength Change in Previously Untrained Men Following Heavy Strength Training. Front. Physiol. 10:1001.  Fibre Type Distribution Muscle fibre type shifted (IIx à IIa) after training period Liu et al (2003). Different effects on human skeletal myosin heavy chain isoform expression: strength vs. combination training. J Appl Physiol 94: 2282–2288, 2003 Physiological Adaptations to Muscular Endurance Training  Muscular Endurance The ability of a muscle to exert submaximal force for extended periods  Performance Increased ME following High Rep (Low load) training Campos et al (1999) Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. Eur J Appl Physiol (2002) 88: 50–60  Fibre Type Distribution Similar shift in fibre type for Low Rep and Int Rep IIx à IIa shift after High Rep (Low load) training Campos et al (1999) Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. Eur J Appl Physiol (2002) 88: 50–60  Capillarization 12 week full-body training 4x/week High Rep/Low Load 20-25 reps Low Rep/High Load 8-12 reps RT induced increased capillarization Holloway et al (2018). Microvascular adaptations to resistance training are independent of load in resistance-trained young men. Am J Physiol Regul Integr Comp Physiol 315: R267–R273 Training Methods  Forced Repetitions After completing a set to exhaustion, the training partner assists the trainee by lifting the resistance just enough to allow the trainee to complete 3 or 4 more repetitions  Rest- Pause After completing 1 repetition, trainee racks the weight and takes a short (10-15s) break before completing the next repetition. Continue process for the desired number of repetitions  Multipoundage (Drop Set) After perform 5 repetitions to near failure, weight is removed from the resistance, and another 5 repetitions are performed. Continue process for the desired number of repetitions.  Circuit Training Perform a series of exercises one after another with minimal rest (15 to 30 s) between exercises. Program Design Variables  Summary Table Goal Level Frequency Load Repetitions Sets Rest (x/week) (%1RM) (#) (#) Period Beginner 2-3 2-3 Strength Intermediate 3-4 > 85% 1-6 3-4 2 - 5 min Advanced 4-6 4-6 Beginner 2-3 2-3 Muscular Intermediate 3-4 < 65 % 12 - 20 3-4 < 30 s Endurance Advanced 4 4  Effect of Exercise Selection What training principle is being illustrated? Similar change in isokinetic strength between exercise groups after training period (Fig 2) Weiss et al, 1999  Effect of Training Frequency More frequent sessions led to more adaptions T1: 1 session/week 6 sets of 12 reps T3: 3 sessions/week 2 set of 12 reps Ochi et al. (2018) Higher Training Frequency Is Important for Gaining Muscular Strength Under Volume-Matched Training. Front. Physiol. 9:744.  Beginner 2 – 3 sessions / week Whole body routines Freq Mon Tues Wed Thurs Fri Sat Sun 2 days/ Whole Rest Rest Whole Rest Rest Rest week Body Body 3 days/ Whole Rest Whole Rest Whole Rest Rest week Body Body Body  Intermediate 3 – 4 sessions / week Whole body routines Split routines Freq Mon Tues Wed Thurs Fri Sat Sun 3 days/ Whole Rest Whole Rest Whole Rest Rest week Body Body Body 4 days/ Upper Lower Rest Upper Lower Rest Rest week Body Body Body Body  Advanced 4 – 7 sessions / week Split routines Freq Mon Tues Wed Thurs Fri Sat Sun 5 days/ Chest, Lower Back, Rest Upper Lower Rest week Shoulders, Body Trapezius, Body Body Triceps Biceps 6 days/ Chest, Lower Shoulders, Rest Chest, Lower Shoulders, week Back Body Arms Back Body Arms  Increase training frequency as client becomes more accustomed to resistance training Freq Mon Tues Wed Thurs Fri Sat Sun 2 days/ Whole Rest Rest Whole Rest Rest Rest week Body Body 3 days/ Whole Rest Whole Rest Whole Rest Rest week Body Body Body 4 days/ Upper Lower Rest Upper Lower Rest Rest week Body Body Body Body 5 days/ Chest, Lower Back, Rest Upper Lower Rest week Shoulders, Body Trapezius, Body Body Triceps Biceps 6 days/ Chest, Lower Shoulders, Rest Chest, Lower Shoulders, week Back Body Arms Back Body Arms  Effect of Exercise Order Strength progression is higher for the exercises performed earlier in a training session Group 1 Bench Press Lat Pull Down Shoulder Press Biceps Curl Triceps Extension Group 2 Dias et al. (2010). Journal of Science and Medicine in Sport 13:65–69  Exercise Order Perform exercises that are most relevant to the training goals first Multi-Joint à Single-Joint Power à Structural à Assistance Single-Joint à Multi-Joint *  Example 1 Alternating Upper Body and Lower Body 1. Clean and Jerk Power } 2. Bench Press 3. Deadlift Structural 4. Seated Row 5. Back Squat 6. Lateral Shoulder Raise 7. Hamstring Curl } Assistance  Example 2 Alternating Push and Pull } 1. Bench Press 2. Bent over Row Structural 3. Incline DB Press 4. Lat Pulldown 4. Triceps Extension 6. Biceps Curl } Assistance  Example 3 Superset Compound Set 1a. Bench Press 1a. Bench Press 1b. Bent over Row 1b. Incline DB Press 2a. Incline DB Press 2a. Squat 2b. Lat Pulldown 2b. Leg Press 3a. Triceps Extension 3a. Bent Over Row 3b. Biceps Curl 3b. Lat Pulldown  Effect of Training Load Physiological adaptations are linked to the intensity and number of repetitions performed Strength Muscle Endurance (1RM) (60% 1RM) Campos et al (1999) Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. Eur J Appl Physiol (2002) 88: 50–60  Progression of Training Load As the athlete adapts to the training stimulus, loads must be increased so that improvements will continue over time When to progress the load? How much to progress the load?  When to progress load? 2-for-2 rule If the athlete can perform two repetitions over their assigned repetition goal in the last set in two consecutive workouts for a given exercise, load should be added to that exercise for the next training session. How much to progress? Progression Guidelines  Effect of Multiple Sets Multiple-Set Single-Set 500 Multiple-set group 450 increased strength, while single-set 400 group did not 350 Pre-Training Post-Training Leg Press (lbs) strength in NCAA Division 1 Football players before and after training Adapted from Kraemer, 1997  Effect of Rest Periods Short rest intervals are not optimal for increasing muscular strength Group 1 – 180 s Group 2 – 90 s Group 3 – 30 s Robinson et al. (1995) Effects of Different Weight Training Exercise/Rest Intervals on Strength, Power, and High Intensity Exercise Endurance. J. Strength and Cond Res. 9(4):216-221  Next Class … Cardiorespiratory Fitness