Muscular Strength

I. Muscular Strength Definition: the amount of force in a single movement A. Fast-twitch muscle fiber ● Contact rapidly and forcefully ● Fatigue more quickly ● Rely more on the anaerobic energy system B. Assessing Muscular Strength ● Measuring the maximum amount of weight a person can lift one time ○ Can use an estimated maximum test (submaximal lift) ○ Need to train for several weeks before testing ○ Retest after 6-12 weeks C. F.I.T.T Principle for Muscular Strength F ----- 2 to 3 days/week I----- 60 to 80% 1 RM (repetition maximum) T----- 1 to 3 sets, 1-5 reps T----- weight training Rest: 3 to 5 minutes II. Muscular Endurance Definition: the ability of a muscle to fire over time repeatedly A. Slow-twitch muscle fibers ● Fatigue resistant ● Don’t contract as rapidly and forcefully ● Rely primarily on the aerobic energy system B. Assessing Muscular Endurance ● Counting the maximum number of repetitions of a muscular contraction a person can perform to fatigue ● Example: How many bodyweight squats can I do until I fail? C. F.I.T.T Principle for Muscular Endurance F----- every other day I-----40 to 60% 1 RM (repetition maximum) T----- 2-5 sets, 15-20 reps T-----weight training Rest: 1 to 3 minutes III. Motor Units ● Made up of a nerve connected a number of muscle fibers ● Small motor units contain slow twitch fibers ● Large motor units contain fast twitch fibers ● Motor unit recruitment happens when strength is required; nerves assist with the action ● Muscle learning is the ability to improve the body’s ability to recruit motor units IV. Physiological Changes and Benefits from Strength Training V. Benefits of Muscular Fitness 1. Improved performance of physical activities 2. Injury prevention 3. Improved body composition 4. Enhanced self-image and quality of life 5. Improved muscle and bone health with aging (tendons, ligaments, maintain motor nerve connections longer) 6. Prevention and management of chronic disease (ex. Diabetes, high blood pressure, osteoporosis) a. Strength training helps prevent and manage cardiovascular disease and diabetes: i. Improves glucose metabolism ii. Increases maximal oxygen consumption iii. Reduced blood pressure iv. Increases HDL (high density lipoprotein) cholesterol and reduces LDL (low density lipoprotein) cholesterol v. Improves blood vessel health VI. Dynamic vs. Static & Training Exercises 1. Dynamic exercise a. Isotonic exercise = movement takes place i. Concentric contractions → shortening, lifting ii. Eccentric contractions → lengthening, lowering 2. Static exercise a. Isometric exercise = no movement takes place i. ii. Advantages: low cost, can do anywhere, rehab an immobilized joint Disadvantages: builds strength at only one position, less muscle hypertrophy, poor transfer to sport skills 3. Eccentric (pliometric) loading ● Places a load on a muscle as it lengthens ● Any resistance training 4. Plyometrics ● Sudden eccentric loading and stretching of muscles followed by a forceful concentric contraction ● Example: the action of lower-body muscles when jumping from a bench to the ground and then jumping back on the bench ● Helps with explosive training 5. Speed Loading ● Moving a weight rapidly as possible in an attempt to approach the speeds used in movements like throwing a softball or sprinting ● Example: doing 5 repetitions as fast as possible 6. Isokinetic exercise ● Exerting force at a constant speed against an equal force exerted by a special strength training machine ● Build muscular strength and endurance VII. Difference in Strength ● Gender ○ Testosterone 5-10x, so the nervous system activates faster thus more power ● Age ○ Motor units disconnect thus muscles become slower in response ● Genetics ○ Muscle cells VIII. Weight Training Safety ● Use proper lifting technique ● Use spotters and collars with free weights ● Be alert for injuries ● Report injuries to your instructor or physician ○ RICE ○ Consult a physician if unusual symptoms occur X. Muscle Fibers ● Individual muscle cells connected in bundles called fascicles ● Made up of smaller protein structures called myofibrils ○ These consist of a series of contractile units called sarcomeres (actin & myosin molecules) ● Satellite cells = provide additional muscle cells nuclei which enhances muscle repair and muscle protein synthesis; improve muscle function ● Hypertrophy → the development of large muscle fibers ● Hyperplasia → muscles increase in size through a separate process; increase in muscle fibers not increase in size of the muscle ● Atrophy → a decrease in muscle fiber size