5. Muscular Strength Flashcards
(35 cards)
What is Muscular Strength?
the greatest amount of force that muscles can produce in a single maximal effort
What is Power? (Formula)
Power - work per unit time - force X velocity.
– Power involves strength and speed.
Benefits of Strength Training?
(5)
Strength provides a foundation for other components of physical fitness such as:
– Cardiorespiratory Capacity
– Muscular Endurance
- Slows down muscle loss
- Increased functional mobility so that daily activities are made both possible and easier
More Benefits of Strength Training
(6)
- Increase the size and strength of muscle fibers
- Increased tendon, ligament and bone tensile strength.
- Stronger muscles better protect the joints
- Improved physical appearance.
- Improved metabolic health.
- Improved mental health
Even More Benefits of Strength Training
(3)
- Better strength in the muscles of the trunk, improves POSTURE.
- Stronger muscles are LESS likely to be STRAINED and INJURED.
- Improvements in self-concept and self-esteem for both patient and athletic populations.
Key Points to Remember about Strength Training (7)
- Quality training and quality recovery
- Continually change up your routine
- Use free weights and machines
- Use whole-body exercises
- Complete a warm-up and cool down
- Make it enjoyable!!!
- Consistency and Variety
Types of Muscular Contraction
- Isotonic contraction
- Isometric contraction
- Isokinetic contraction
What is Dynamic/Isotonic contraction?
– iso (same) tonic (tone/force/weight) tension is the same throughout the range of motion.
- Machines or free weights
Machine for Dynamic Movements
What is an Isometric Contraction?
Isometric contraction - static contraction. Tension is developed but there is no change in the angle of the joint or the length of the muscle.
What is Isokinetic Contraction?
Isokinetic contraction -
the muscle is shortened at a constant velocity determined by instrumentation which allows a person to exert maximal force throughout the full range of motion
Purpose of Strength Assessment (5)
- Assess muscular FITNESS
- Identify specific areas of WEAKNESS
- Monitor PROGRESS in a rehabilitation program
- Measure the EFFECTIVENESS of a resistance training program
- MOTIVATION for training
3 Strength Assessment Techniques
- One Repetition Maximum
- Estimated from Variable Repetition Maximum - Dynamometer Techniques
- Computer-Assisted, Isokinetic Methods
What is a One Repetition Maximum? (3)
- Maximum amount of weight lifted once.
- Use free weights or machines that allow dynamic muscle contractions
- Only appropriate for very experienced
How to Estimate One Repetition Maximum?
(1 RM)
- Estimated from repetitions to failure on machines
- Variable-repetition maximum tests.
- 1 RM = (weight lifted) / [1.0278 - (n X 0.0278)]
- n = repetitions to failure (not to exceed 10)
- Safer than using 1-RM, especially with beginners
What are Dynamometer Techniques?
A strength-testing dynamometer usually consists of a spring of some type which is deformed by a certain amount when a specific force is applied to it.
(eg) - hand grip dynamometer
- measures isometric strength
- relatively inexpensive, and high reliability if the body position is carefully standardized for each trial of the test.
- high correlation between grip strength and
longevity
What are Computer-Assisted, Isokinetic Methods?
- equipment such as Biodex, KIN/COM, etc.
- has a computer which can be programmed at any initial and final force, angle, velocity, or number of repetitions.
- measure peak torque using a force transducer and joint angle using an electrogoniometer.
- extensive manipulations can be performed on collected data using computer software
- accurate and reliable, but expensive
- used for research and elite athlete assessment
What are the 7 Strength Assessment Considerations?
- STANDARDIZED instructions should be given before testing.
- If a warm-up is given, it should be of
uniform DURATION and INTENSITY - Ensure that the ANGLE of measurement
on the limb or test device is consistent
among subjects - Consider individual differences in body SIZE and PROPORTION when evaluating strength scores between individuals and groups.
- Test and training mode SPECIFICTY is important for optimal expression of true strength gains.
- SAFETY is an important consideration when performing strength evaluations. Ensure that all equipment is in proper working order and that standard weight room safety procedures are being followed.
- Test administrators should be WELL-TRAINED and have a thorough understanding of all testing procedures and protocols.
5 Effect Of Various Factors On Strength
- Muscle Cross-Sectional Area
- Body Size
- Muscle Fiber Composition
- Mechanical Factors
- Sex and Age
What is Muscle Cross-Sectional Area?
- There is a strong positive relationship between muscle CSA and strength.
- Muscles increase in strength by increasing their size and by enhancing the recruitment and firing rates of their motor units.
2 Types of Tissue/Cell Growth
- Hypertrophy - an increase in the size of a cell such as a muscle fibre
- Hyperplasia - an increase in the number of cells such as adipose cells
What accounts for most, if not all, of the increase in muscle cross-sectional area due to an overload training program?
hypertrophy
Body Size Effect On Strength
- There is a positive correlation between body size or mass and absolute strength.
- There is a negative correlation between body mass and the strength/mass ratio.
The strength-to-mass ratio directly reflects an athlete’s ability to accelerate his or her body. - All else being equal, smaller athletes are stronger kilogram for kilogram than larger athletes.
Relationship Between Body Size and Strength
Large athletes dominate sports events which require a high level of absolute strength (e.g., throwing events in track and field)
Smaller athletes dominate sports events which require a high strength/body mass ratio (e.g., gymnastics).
