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Unformatted text preview: Improving Muscular Strength, Endurance and Power
Lifetime Fitness Lesson 4
Chapter 5 Essential component of physical fitness Strength Why is muscular strength important for everyone? The ability of a muscle to generate maximum force against some heavy resistance Maintain normal strength is important for healthy living (gait, posture, function) Strength training plays an important role in not only fitness programs but also injury prevention and rehabilitation How are strength and muscular endurance related? Muscular endurance Ability to perform repetitive muscular contractions against some resistance for an extended period of time As strength increases, endurance also increases Endurance is often more important than strength as it is critical for everyday function Isometric contractions Type of Skeletal Muscle Contraction Concentric contraction Muscle contraction that produces tension but does not result in a change of muscle length Considerable force can be generated without movement occurring Muscle shortening occurs while tension is developed to overcome a resistance Muscle contraction that involves a lengthening of the muscle Eccentric contraction Fasttwitch vs. Slowtwitch Fibers Muscles are made up of fast and slow twitch fibers Each has distinct metabolic and contractile properties Slow twitch fibers Fast twitch fibers Generally found in muscles responsible for posture (gravity resistant muscles) Tend to be more fatigue resistant Tend to be located in muscles that produce more powerful, explosive, strength movements Fiber type properties can be modified slightly through specific types of training making them more fast or slow twitch in nature Fiber Size What determines how much strength you have?
Crosssectional diameter of the muscle fibers Greater the crosssectional diameter the stronger it is Increases in cross sectional diameter of the muscle is referred to as hypertrophy Atrophy is a decrease in muscle size Muscle Size Strength is a factor of the number and diameter of muscle fibers However, strength can also be improved through training Biomechanical Factors Bones, muscles, and tendons create a series of levers and pulleys that generate force against external objects Particular attachments of muscles to bones will determine how much force the muscle is capable of generating Males and females gain strength to age 2025 After age 25, maximal strength begins to decline 1% of the remaining maximal strength each year Age Age Strength/body weight ratios must also be considered when discussing strength development Females tend to have lower ratios due to higher body fat percentages The ratio can be improved through training by increasing strength/lean body mass and decreasing body fat % Strength training guidelines for males and females should be the same Level of Physical Activity Loss of strength is linked to declines in physical activity Continued training helps to maintain strength and reduce strength reduction over time Exercise will have an impact on minimizing losses relative to endurance and flexibility as well Reversibility Gains in muscular strength resulting from resistance training can be reversed Declines in training or stopping all together will result in rapid decreases in strength Overload For a muscle to improve in strength it must be forced to work at a higher level Without overload the muscle will be able to maintain strength when training continues at a level of resistance at which the muscle is accustomed Strength gains require increasing efforts against progressively increasing resistance
No gains will be made More a factor in muscular endurance training Some may be better for achieving certain goals than others Types of training
Progressive resistance exercise Isometric exercise Isokinetic exercise Circuit training Plyometric training Calisthenics Functional training Core stabilization training What are the techniques of resistance training? Progressive Resistance Exercise Most commonly used and most popular Utilizes isotonic contractions (concentric & eccentric) to build strength Machines vs. Free Weights Variations exist between free and machine weight lifting Motion restrictions, levels of muscular control required, amount of weight that can be lifted Both are safe to use with proper technique Machines tend to be safer Use of a spotter is often necessary with use of free weights Weight can easily be adjusted with machines and can be safely dropped if necessary Free weights pose minimal motion restrictions and require increased levels of muscular control Spotter functions to protect the lifter, make recommendations and provide motivation Using concentric and eccentric contractions Both should be incorporated into training Greater force can be generated with eccentric contractions and tend to be more fatigue resistant Mechanical efficiency of eccentric exercise may be several times higher than that of concentric exercise Concentric phase of lift should last 12 seconds, eccentric phase 24 seconds Accommodating Resistance Using a cam and pulley system changing force capabilities are alleviated Allows for variable resistance throughout the motion It is debatable as to whether or not this actually occurs Terminology associated with weight training
Intensity or amount of weight Repetitions Number of sets Recovery period Frequency of training The FITT principle can also be applied There is no such thing as an optimal program Selecting a Starting Weight When training should be able to perform 3 sets of 68 repetitions with 6090 seconds rest between sets Progression Increases should occur in increments of 10% Should still allow individual to do 6 repetitions for 3 sets Training of a particular muscle group should occur 34 times per week (not on successive days) Muscles must be overloaded in order to meet program goals Frequency Should you exercise differently to improve muscular endurance? Training for endurance enhances strength and vice versa Training for strength should involve lower repetitions at heavier weights Training for endurance requires lower weight being lifted for 3 sets of 1015 repetitions Persons that possess greater strength also tend to exhibit greater muscular endurance Isometric Exercise Contraction where muscle length remains unchanged Muscle contraction that lasts 10 seconds and should be perform 510 times/daily Quick, effective, cheap, and good for rehabilitation Only works at one point in ROM, produces spiking of blood pressure due to Valsalva maneuver Isokinetic Exercise Muscle contraction occurs at a constant velocity Maximal and constant resistance throughout the full range of motion Maximal effort = Maximal strength gains Rely on hydraulic, pneumatic, and mechanical pressure systems Disadvantages Typically involves 3 sets of 1015 reps
Cost Need for maximal effort/motivation Circuit Training Combination of exercise stations 8 12 stations, 3 times through Design for different training goals Flexibility Calisthenics Aerobic exercise Functional Training Uses integrated exercises designed to improve functional movement patterns Training for strength and neuromuscular control Training in 3 planes of motion Involves integration of proprioceptive feedback to perform triplanar movement tasks Avoids isolated single plane training Also works on core strength and flexibility Plyometric Exercise Rapid stretch, eccentric contraction followed by a rapid concentric contraction to create a forceful explosive movement Rate of stretch vs. magnitude Jumps, bounds, medicine ball throws Very technical training skills must be learned with appropriate technique Advanced training Should adhere to 3 sets of 68 repetitions Enjoyable exercise that is not always regimented Used to enhance muscular strength Calisthenic Strengthening Exercises Free exercise Isotonic training that utilizes gravity and body weight as resistance No weights are required Full range of motion activities that may be beneficial for flexibility Exercise caution often involves bouncing Adequate progressions and warmup are necessary Can be used for cardiorespiratory endurance training Intensity, frequency and duration are appropriate Must minimize rest for cardio training effect Core Stabilization Training The core is the lumbopelvichip complex Center of gravity is located there Core training works to improve
Dynamic postural control Muscular balance Functional strength Neuromuscular efficiency Body must be adequately stabilized Allows muscles (prime movers) to generate strong, powerful, movements Weak core can lead to inefficient movements and potentially injury Core training plan Should be systematic, progressive and functional Needs to be safe, challenging, stress multiple plans, and incorporate a variety of resistance equipment Begin with exercises that allow for stability and neuromuscular control Summary Strength training is important for overall health. The ability to generate force depends on physical properties and mechanical factors. The key to improving strength is using the principle of overload. A number of different resistance training techniques can improve muscular strength. ...
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This note was uploaded on 03/20/2008 for the course LFIT 104 taught by Professor Humphries during the Spring '08 term at UNC.
- Spring '08