Resistance Training Flashcards
Resistance Training: Gains in Muscular Fitness
- After 3 to 6 months of resistance training
- 25% to 100% strength gain
- Better force production
- Ability to produce maximal movement
- Greater absolute gains for young men than for others
Mechanisms of Muscle Strength Gain
Hypertrophy vs atrophy
– Increased muscle size = Increased muscle strength
Sources of Strength Gains
- Increased muscle size
- Altered neural control
Mechanisms of Strength Gain: Neural Control
- Strength gain cannot occur without neural adaptations via plasticity
– However, strength gain can occur without hypertrophy
– Strength is part of the motor system, not only of the muscle - Essential elements include
– motor unit recruitment
– stimulation frequency of motor units
Mechanisms of Strength Gain: Motor Unit Recruitment
Motor units normally are recruited asynchronously
However, synchronous recruitment leads to strength gains
– Facilitates contraction
– May produce more forceful contraction
– Improves rate of force development
Resistance training -> causes synchronous recruitment
Strength gains may also result from greater motor unit recruitment.
– Increases neural drive during maximal contraction
– Increases frequency of neural discharge (rate coding)
– Decreases inhibitory impulses
Likely that a combination of the following for strength gains:
- Improved motor unit synchronization
- Motor unit recruitment
Mechanisms of Strength Gain: Autogenic Inhibition
Normal intrinsic inhibitory mechanisms
- Example: Golgi tendon organs
- Inhibit muscle contraction if tendon tension too high
- Prevent damage to bones and tendons
Inhibitory impulses decrease with training
- Therefore - Muscle can generate more force
Mechanisms of Strength Gain: Muscle Hypertrophy
Hypertrophy: increase in muscle size
Transient hypertrophy (immediately after exercise bout)
- Due to edema formation from plasma fluid
- Gone within hours
Chronic hypertrophy
- Structural change in muscle
– Fiber hypertrophy,
– Fiber hyperplasia, or both
Mechanisms of Strength Gain: Muscle Hypertrophy
- Maximized by high-velocity eccentric training (high stress)
- Disrupts sarcomere Z-lines (protein remodeling)
- Stimulated by intensities as low as 30% 1RM and as high as 90%
- Caused by both high-rep (low-load) and low-rep (high-load) training
Mechanisms of Strength Gain:Fiber Hypertrophy
More myofibrils
More actin, myosin filaments
More sarcoplasm
More connective tissue
Resistance training leads to an increase in protein synthesis
Mechanisms of Strength Gain:Hormones and Hypertrophy
Fiber hypertrophy facilitated by testosterone
- Natural anabolic steroid hormone
- Synthetic anabolic steroids leads to a large increase in muscle mass
Growth hormone (GH)
Insulin-like growth factor 1 (IGF-1)
Mechanisms of Strength Gain:Neural Activation and Hypertrophy
Short-term increase in muscle strength
- Increase in 1RM
- Due to neural activation
- Neural factors critical in first 8 to 10 weeks
Long-term increase in muscle strength
- Associated with significant fiber hypertrophy
- Protein synthesis requiring time to occur
- Hypertrophy major factor after first 10 weeks
Mechanisms of Strength Gain/Loss:Atrophy and Inactivity
Reduction or cessation of activity
- Cause major change in muscle structure and function
Data from Limb immobilization studies
Data from Detraining studies
Mechanisms of Strength Gain/Loss:Immobilization
Major changes after just 6 hours of immobilization/inactivity
- Lack of muscle use see reduced protein synthesis
- Initial process of muscle atrophy
First week: strength loss of 3%-4% per day
– Decrease size (atrophy)
– Decrease neuromuscular activity
Effects on type I and II fibers (however – effects are reversible)
- Cross-sectional area decrease, cell contents degenerate
- Type I (slow twitch) is affected more than type II
STRENGTH CHANGES BEFORE, DURING AND AFTER TRAINING
Explain – How can you use this information to assist our patients/clients?
Women
Pre-20 = pretraining; post = 20 wks training
Pre-6 = stop training for 6 wks; post = 6 wks of retraining again
Not staying consitently active will result in strength losses. After building a large amount of strength you will loss the amount of strength significantly but can also train again and regain that same strength back quickly.
Soreness - What is the difference between acute muscle soreness and delayed onset muscle soreness?
Acute Muscle Soreness: pain felt during and immediately after exercise due to accumulation of H+ and tissue edema. Often during heavy endurance or resistance training. Disappears within few minutes to several hours.
DOMS: 24-48 hours after exercise. Type 1 muscle strain resulting in muscle stiffness. Eccentric movements are theorized to initiate DOMS. Involves inflammation which brings neutrophils, cytokines and macrophages.
