4: Muscular Fitness: Strength and Endurance Flashcards
Muscle Strength
– Maximal amount of force a muscle can produce
Muscle Endurance
– Ability of a muscle group to perform repeated contractions at a submaximal level
Physiological Benefits of Good Muscular Fitness
– Improved bone mass (reduced risk of osteoporosis)
– Improved glucose uptake (better blood glucose control thus reduced risk of Type 2 diabetes
– Increased fat-free mass and resting metabolic rate (improved body composition and weight control)
– Improved ability to perform activities of daily living (ADL)
– Improved physical activity/sport performance
– Less risk of musculoskeletal injuries and low back pain
– Offset age-related changes in muscle (i.e. loss of muscle mass, strength and endurance)
Why measure muscular strength/endurance
o Test upper body strength
o Test for muscle imbalance (eg. weak hamstrings – train hamstrings)
o Test in older people to note if strength is healthy/normal
Factors to Consider for Assessing Muscular Strength and Endurance
o There are 700 skeletal muscles with varied performance levels.
– Therefore, there is no single measurement that provides an assessment of an individual’s muscular strength or muscular endurance.
o Type of contraction, familiarization, method of loading, technique, positioning etc — all influence assessment and therefore the accuracy & interpretation of the results.
Types of Contractions
o Static/Isometric
o Dynamic/Isotonic
o Dynamic/Isotonic contraction
– Generation of force to move and object
– Muscle is shortened during contraction (Concentric contraction)
– Muscle is lengthened during contraction (Eccentric contraction)
o Static/Isometric
– Generation of force without movement
(Concentric contraction)
Muscle is shortened during contraction
(Eccentric contraction)
Muscle is lengthened during contraction
familiarisation
o Some assessment tasks are uncommon to client
– Performance is improved through learning & practice (learning effect)
o Most clients will require a learning and familiarization period
– Technique and equipment
o Include a warm-up prior to assessment (light aerobic exercise and low intensity reps of the assessment task)
– Increase blood circulation to muscles
– Help refamiliarize the client with the assessment task.
Methods of Loading for Assessment of Strength and Endurance
o Methods used to load the muscle during assessment
– Free weights
– Resistance exercise machines
– Individual’s body weight
o Discuss the pros & cons
– Client safety
– Isolate individual muscle groups
– Range of tests
– Equipment
Proper Positioning & Correct Technique
o Essential for free weights, machines, and body weight
o Improper positioning or incorrect technique potentially allows other muscle groups to contribute to movement of load.
o Proper positioning and correct technique
– allows for accurate measurement of the muscle group being assessed (i.e. isolates the muscle group)
– Necessary for the safety of the client
Standardised Procedures
o Reliability and accuracy of measurements are enhanced by following standardised procedures and performing tests and repeat tests consistently
– Proper positioning throughout test
– Correct technique throughout the test
– Familiarization period
– Use same equipment/method to load the muscle
– Speed of movement consistent
– Full range of motion (ROM)
o Interpreting results using normative data, need to use the same procedures including the same equipment as was used to develop the norms
What are the major muscle groups
- Deltoids
- Latissimus dorsi, Trapezius, Rhomboids
- Pectoralis
- Rectus abdominis
- Gluteus maximus
- Vastus lateralis and rectus femoris
- Biceps femoris
- Soleus and Gastrocnemius
strengths assessment
o No single measure of muscular strength for an individual
o Best case scenario: assess a range of different muscles/muscle groups, produce a composite score to assess overall strength
o Limited for individuals with above average strength in some muscle groups and below average in others
Strength Assessments: Static
o Dynamometers
– Grip strength
– Maximal force is applied and read.
– Hand & forearm muscles
– Used a general test of strength
Grip Strength
o Strengths: inexpensive, easy to perform, easy to interpret, widely used test of general strength, suitable for all clients, good reliability (if standardised procedures are followed).
o Limitations: Good measure of grip strength (good validity) but poor measure of general strength in some people (poor validity)
o Requirements: Grip dynamometer
o Factors affecting reliability and validity of the
o measurement will be discussed in the practical session
Strength Assessments: Dynamic
- Repetition Maximum (1 - RM)
o Gold standard test for assessing dynamic strength
o Maximum amount of weight a client can lift in one rep through full ROM in a controlled manner with good posture
o Performed with any muscle group
o Can be tested using free weights or machines
– Bench press—norm for upper body
– Leg press—norm for lower body
1-RM Tests
o Strengths: gold standard, measure a range of muscle groups, use free weights or machines, excellent reliability, and validity (if standardised procedures are followed), interpret results against norms.
o Limitations: need to be familiar with technique, suitable for experienced clients only, client safety
o Requirements: Good technique, equipment, spotter for safety reasons
o Many factors can affect reliability and validity of the test
o Alternatives: 3 or 5-RM used to predict 1-RM value using an equation
Endurance Assessments
o Fixed number of contractions in a defined period (e.g. 1 minute)
o Maximal number of contractions at set rate and resistance/load until exhaustion
o A static contraction held for time
o Tested using free weights, resistance machines or body weight
Endurance Assessments: Dynamic
(Field Tests)
o Able to test large groups of people
o No equipment required
o Common tests include curl-ups and push-ups (modified push-up)
o Maximal repetitions performed with proper technique in e.g. 1 min or until exhaustion.
o Suitable for a range of clients
o Standard technique and procedures is crucial (for interpretation using normative values).
o Strengths and limitations
Assessing Muscular Fitness in Older Adults and Clinical Groups
o There may be more appropriate assessments of muscular strength and endurance (MS & E) for these groups (covered in Alison’s 4th year class)
– Safer
– Assess aspects of muscular fitness that are important for common everyday activities
