Physical Activity & Exercise
What is the difference between exercise and physical activity?
Physical activity is any movement that is carried out by the muscles that require energy. In other words, it is any movement a person does.
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Exercise is a planned, structured, repetitive and intentional movement.
What is muscle strength and what factors are enhanced by muscle strength training?
--> muscles’ ability to exert force
- Use muscle strengthening exercises when function or sports performance is compromised
Factors that are stimulated and enhanced by muscle strength training are:
- Increased glycogen and protein storage in the muscle
- Increased vascularisation
- Recruitment of neighbouring motor units
- Increased cross-sectional area of the muscle fibre and muscle cross sectional area
What is muscle power?
--> force produced per unit time; product of force and velocity --> requires muscle strength as a prerequisite
• As velocity of movement increases, the force that muscle can produce decreases, therefore max power is achieved at a compromised level
What is plyometrics?
--> high intensity, explosive muscular contractions combining strength and speed at slightly lower load than traditional power training
• form of power training
• involves rapid deceleration followed by immediate, rapid acceleration
• muscles undergo rapid elongation followed by immediate shortening (stretch- shortening contraction), utilising the elastic energy
• sport-specific exercises
• can lead to DOMs
What is an isolation vs compound exercise?
Isolation - single joint
Compound - whole kinetic chain
What are the benefits of physical activity?
• reduce the risk of, or help manage, type 2 diabetes and cardiovascular disease
• maintain or improve blood pressure, cholesterol and blood sugar levels
• reduce the risk of some cancers
• prevent unhealthy weight gain and help with weight loss
• maintain strong muscles and bones
• create opportunities for socialising and meeting new people
• help develop and maintain physical and mental wellbeing.
In a clinical setting :
• Tissue healing and adaptations : cellular proliferation & matrix remodelling in tendons, muscle hypertrophy, positive tissue response in articular cartilage, bone density
• Improve/maintain strength, endurance, power and flexibility
• Reduce pain
• Improve proprioception and balance
• Injury prevention
What are the exercise prescriptions for muscle strength?
Load magnitude : increased load will increase strength --> 60-70% 1RM for novice/intermediate, >80% 1RM for advanced/experienced
Repetitions and sets : 8-12 reps, 1-3 sets (3 sets most effective) --> 2-3min rest in between sets, 2-10sec rest between reps may allow increased loads
Time under tension : velocity (slow-moderate) --> start at 1-2sec for untrained individuals, increased tension time may increase strength gains
What are the adaptations of muscle power?
• Neural & muscle architecture
• motor-unit recruitment, rate coding (motor unit firing frequency), and synchronization
• recruitment of high-threshold motor units and preferential recruitment of larger motor units
• increase in muscle cross sectional area
What are the adaptations of plyometrics?
• See muscle power but intensity/load dependent
• changes in muscle tendon complex + changes in tendon stiffness
• Suitable for later stage exercise programs
What is an Isotonic exercise/movement?
--> movement without a change in muscle tension (ie. bicep curl at same weight, changes muscle length but muscle tension required to lift it remains the same)
What are the PA guidelines for adults?
• at least 150–300 min of moderate-intensity aerobic physical activity / at least 75– 150min of vigorous-intensity aerobic physical activity
• muscle-strengthening activities at moderate or greater intensity that involve all major muscle groups on 2 or more days a week. • limit amount of time spent being sedentary. Even light intensity provides health benefits.
• aim to do more than the recommended levels of moderate-to vigorous physical activity
Must work out in assessment at what level you should start for your client (based on pyramid)
What are the muscle strength adaptations?
1. Client will start to feel stronger (due to increase in recruitment of motor units) : neural: 1 to 3 weeks
2. Client will see further strength increase (hypertrophy from enlargement of individual fibres not increase in fibre numbers) : approx. 6- 8 weeks with progressive resistance training
What are the exercise prescriptions for muscle power?
Load magnitude : max strength is an important foundation for power --> start w/ light loads (<60% 1RM), vary loads in trained individuals to optimise gains
Repetitions and sets : 3-6 reps, 3-6 sets; rest 3-5mins between sets, increased rest can help optimise movement velocity
Time under tension : explosive movements --> vary velocity according to patient needs, increase velocity to optimise peak power gains
What are exercise prescriptions for plyometrics at all intensities?
Low intensity - 10-30 reps, 10-15 sets (medicine ball, low short hops, two leg jumps, hops and steps
Moderate Intensity - 10-25 reps, 10-20 sets (two leg jumps from height upper body, med ball for distance shot)
max + sub-max intensity - sub = 5-15 reps and 5-15 sets (high reactive jumps, shock hits heavy, implements in depth jumps) max = 3-5 reps and 10-20 sets (rest in between sets, 5-7mins, 8-10mins)
What is an open chained vs closed chain exercise?
Open chain - segment furthest away from the body is free and not fixed to an object
Closed chain - most distal segment fixed by an object
What is muscle activation/control?
=> refers to how the CNS produces purposeful, coordinated movements in its interaction with the rest of the body and with the environment
Pain & Swelling --> altered muscle activity and motor control --> increases stress on other structures/increased forces across joint surfaces
What is muscle endurance and its adaptations?
--> Ability of muscle/muscle group to repeatedly exert submaximal resistance
Adaptations :
• Improved oxygen transport
• Higher intramuscular lipid concentration
• Greater efficiency of oxygen use through
• Increased capillary density
• Myoglobin concentration
• Number and size of mitochondria
• Greater activity and oxidative enzymes within mitochondria
What is flexibility?
- stretching type exercises important for patient that have had inflammation, pain and stiffness that can limit joint ROM
- Can increase musculotendinous flexibility (secondary to spasm)
- Prolonged decrease in ROM can also cause adaptive tightening of the joint capsule and pericapsular tissues
Static Stretches
• to increase ROM
• greatest change occurs between 15 and 30 seconds
• no increase in muscle elongation occurs after 2 to
4 repetitions
• Also decreased muscle strength immediately following static stretch – after exercise or as rehabilitation program
Adaptations :
• Muscle fibre elongation: area of overlap between thin and thick myofilaments decreases
• Increased stretch tolerance
Give definitions for the following : concentric, eccentric, isometric and isokinetic
Concentric - muscle shortens during contraction (ie. bicep curl up from extension to flexion)
Eccentric - muscle lengthens during contraction (ie. bicep curl down from flexion to extension)
Isometric - muscle length does not change during contraction (ie. holding weight in maintained position)
Isokinetic - exercise performed at a constant speed (ie. running, cycling)
How do we address a decrease in muscle activation in clients?
Specific exercise following muscle decrease in clients :
--> exercise may be isometric or during movement or a functional activity. Focus is on activating the muscle or muscle group.
Goals :
- Neuromuscular adaptation
- Increased ability to voluntarily recruit motor units
Can use observation, palpation, EMG to assess/give feedback.
What are the exercise prescriptions for muscle endurance?
Load magnitude : star low (<50% 1RM) --> focus on volume + exercise form
Repetitions and sets : >15 reps, 3 sets minimum (> nbr of sets = more effective) --> rest in between sets 30-90secs (shorter rests = better endurance)
Time under tension : slow-moderate velocity --> untrained individuals 4-5sec per rep
Give definitions for the following : exercise dosage, reps, sets and hold
Dosage : total amount of exercise prescribed, encompasses nbr of sets, reps, hold time,
frequency, intensity.
Repetitions (Reps) : 1 complete movement of an exercise.
Sets : group of repetitions performed without resting. Hold Time : how long particular position should be maintained.