Lecture 11 - Resistance Training III Flashcards
What role does metabolic stress play in muscle hypertrophy?
Several mechanisms have been
postulated linking metabolic
stress with muscle hypertrophy
-build up of metabolites
- muscle fatigue
Blood flow restriction training and muscle hypertrophy
Works while light resistance training but should not be used/not effective in use after muscle fatigue
Motor unit recruitment with fatigue
Fatigue leads to a reduction in a muscle’s force producing capacity
- At submaximal intensities, as some
muscle fibres fatigue, more motor units are recruited to maintain force requirements
Do acute hormonal alterations impact muscle adaptations?
Mixed and limited evidence supporting role for acute hormonal alterations
in muscle hypertrophy
- If acute endogenous hormone production does play any role in mediating muscle hypertrophy, it is probably of minor practical consequence
Summary of mechanisms of muscle hypertrophy
The size principle dictates that smaller, predominantly slow twitch motor units will be recruited before larger, predominantly fast twitch motor units
As muscle fatigue progresses, motor unit recruitment increases to compensate for reduced force capacity in fatigued fibres, thereby recruiting more fast twitch motor units
Mechanical tension is the most important factor in training-induced
muscle hypertrophy (mTOR and calcium)
There is conflicting evidence for role of muscle damage and metabolic stress
Homeostasis, stress, and adaptation in training
Homeostasis - “A self-regulating process by which an organism can maintain internal stability
- Maintains optimal conditions for functioning
A stressor is anything that disrupts internal stability
The stress-response occurs to reestablish internal stability
Adaptation - adapting to stimulus
Stress-recovery -adaptation
The level of stress imposed is theorized to impact the level of subsequent
adaptation
- Training “load” must be
sufficient to induce adaptation - Intensity
- Volume
- Frequency
Progressive overload principle
* Gradual increases in training
load are required over time. The more we do the more we might improve
If not reach accomadtion (plateau) or overtraining (decrease)
Minimum effective dose and diminishing returns in training
Minimum effective dose:
smallest amount of an input to
acquire desired result
Diminishing returns:
a decrease in output for a given increase in input
Typical exercise categories
Upper body push
* Vertical
* E.g., military press
* Horizontal
* E.g., bench press
Upper body pull
* Vertical
* E.g., pull-ups
* Horizontal
* E.g., rows
- Squat
- Lunge
- Hinge
- Carries
- Core
- Isolation movements
- E.g., single joint machine exercises
“Safe” vs “unsafe” or “tolerable” vs “not tolerable”
In general, resistance training is very safe
- Soft tissue injuries arise when load exceeds the tissue’s capacity to handle that load
- Injuries or detraining will tend to reduce our tissue’s capacity to handle load
(Properly progressed) training will tend to increase our tissue’s capacity to handle load
- The body has an incredible ability to adapt!
Resistance training terminology
Exercise: A movement pattern used to stimulate a muscle or group of muscles
* E.g., squat, bench press, deadlift
Repetition (rep): The single execution of an exercise from the desired starting point, and back to the desired starting point.
Set: A collection of (semi) continuous repetitions of an exercise, separated by bouts of rest
Rest time: Time spent allowing fatigue to dissipate between repetitions, sets, exercises, and training sessions.
Tempo: How fast an exercise is performed. Often broken down into each segment of an exercise – e.g., eccentric phase, middle of movement, concentric phase
Intensity/load:
Typically relates to:
Velocity or power output or Magnitude of resistance
Volume: Amount of work done in a given time frame
Frequency/density: number of times something is done per time. 4 times per week
Prescribing relative intensity in resistance training
Traditionally, most common approach is using % of 1 repetition maximum (1RM)
Pros: Simple to prescribe to variety of populations
Cons: Requires directly testing 1RM (or at least estimating it from other near maximal test).
Does not account for change over time
INSTEAD:
As an alternative to %1RM, prescribing based on rate of perceived exertion (RPE)
Pros:
Equally simple to prescribe as % 1RM
Cons:
* Some people under- or overstate what they truly felt
What impact does training
intensity have on strength and
hypertrophy adaptations?
As long as you go to near failure muscle hypertrophy will occur
Low rep with higher weight will improve strength
Improve what we practise
Increased neural adaptations at high vs low load strength training
Heavier load greater strength increase
Hypertrophy as long as high intensity
