Resistances factors affecting strength type of muscle

resistances
-Factors Affecting Strength
-Type of Muscle fiber; the overload principle; specificity of training; training volume;
periodization; neural stimulation
3/20/16
-Neural Stimulation
-Motor Neurons: Nerves that connect CNS to muscle
-Single motor neurons branch and attach to multiple muscle fibers
-Motor Unit: Motor neuron and the muscle fibers it innervates
-Number of fibers varies from a few to a 1,000
-Stimulation of a motor neuron causes muscle fibers to contract maximally or not at all

-Strength of muscle contraction is determined by variations in # of muscle fibers
innervated and frequency of their stimulation
-Types of Muscle Fibers
-Slow-twitch (red fibers): capacity for aerobic work
-Fast-twitch (white fibers): capacity for anaerobic work; produce more overall force;
quick, powerful movements
-Proportion of slow/fast twitch fibers are genetically determined
-Strength training increases capacity for both types of fibers
-Overload Principle: Demands placed on a system must be increased systematically and
progressively over time to cause physiological adaptation
-Strength Gains
-Achieved through increased ability of individual muscle fibers to generate a stronger
contraction OR recruiting a greater proportion of total available fibers for each
contraction
-Muscles need to be taxed beyond accustomed loads to increase capacity
-How to overload in strength training
-Increasing intensity
-Increasing number of repetitions
-Increase or decrease the speed of repetitions
-Decrease or increase the rest interval
-Increase volume (total reps multiplied by resistance used)
-Principle of Specificity of Training
-For a muscle to increase in strength or endurance, training program must be specific to
obtain desired effects
-Also applies to activity or sport-specific development: Specific Adaptation to Imposed
Demands (SAID) training
-Training Volume
-Volume: sum of all reps performed multiplied by resistance used
-Volume can be amplified by increasing: Exercises, Sets per exercise, Repetitions per set
-Periodization: Alternating intensity and volume of training
-Used to prevent overtraining (emotional, behavioral, and physical condition marked by
increased fatigue; decreased performance; persistent muscle soreness; mood disturbances;
and feelings of staleness or burnout as a result of excessive physical training)
-To avoid overtraining, volume should not increase by more than 5% from one phase to
the next
-Principles Involved in Strength Training: Mode; Resistance; Sets; Frequency; Volume
-Mode of Training
-Two types of training methods to improve strength
-Isometric (static) Training: Muscle contraction that produces little or no movement, such
as pushing or pulling against an immovable object
-Strength gains are specific to the angle of muscle contraction
-Dynamic Training: Muscle contraction with movement; full range of motion
-Improvements measured easily by amount lifted
-Two Action Phases:
-Concentric- Shortening of a muscle (positive resistance)
-Eccentric- lengthening of a muscle (Negative resistance)