Week 6 Flashcards
Define rate coding
The force exerted by a muscle during a voluntary contraction depends on the number of motor units recruited for the action and the rates at which they discharge action potentials
With endurance training the following adaptations occur in the neural system:
Motor unit discharge rate decreases
The central nervous system can increase the strength of muscle contraction by the following (2):
- Increasing the number of active motor units (ie, spatial recruitment)
- Increasing the firing rate (firing frequency) at which individual motor units fire to optimize the summated tension generated (ie, temporal recruitment)
Intensity is defined as either….
- The % of a 1-repetition maximum (RM) lift
- The absolute load for 3-RM, 5-RM, 10RM, etc prescription (predict 1RM from higher RM)
The observational history of our field dictated the belief that higher intensities MUST be more effective for strength, and lower intensities MUST be more effective for hypertrophy - T/F?
Not completely true
When higher volume was accrued, intensity did/did not matter
did not
“intensity” is important for upregulating ________ mechanisms, but if you allow for ______ to become higher ______ not as important
hypertrophic, but if volume higher = intensity less important
as you get closer to repetition failure (RM) you will eventually achieve ….?
Full recruitment of the motor unit pull (although hard to confirm due to use of EMG in study, not very accurate on recruitment)
Low intensity exercise elicits ….?
Greater peripheral muscle fatigue (may reach similar overall volume)
Motor unit recruitment is generally different between high and low intensity contractions, apart from….?
where we increase volume and require a low intensity contraction to be performed to FAILURE.
Low intensity contractions appear to achieve similar levels of ____ ____ ____ to a high intensity contraction, BUT only…..?
Central motor output, only towards the end of the contraction
Biggest predictor of ‘failure’ in high intensity was ….?
Perceived PAIN (nearly double for the low intensity contraction group)
When you increase ‘volume’ of repetitions by 4-5x that of a higher intensity load (i.e. 20 reps at 80-90% vs 90-100 reps at 40%) you will likely achieve similar ….?
Central motor output and upregulation of muscle protein synthesis the lower volume but many more reps/work
So for one ‘muscle group’ the question for clinical application regarding hypertrophy is _____ (and why)
Time.
- time to complete a ‘light’ multi-set protocol is around 50% longer than a ‘heavy’ multiset protocol (more reps vs less reps)
- With added fatigue and pain die to going to failure
Accumulation of ‘_____’ probably more important for novices to enhance outcomes
volume
For novices:
- Emphasis on strength….?
- Emphasis on hypertrophy…?
- If use ‘heavier’ weight (e.g. 80%+) you can use…?
- If use lighter weight you must prescribe….?
- Emphasis on strength: use higher intensity
- Emphasis on hypertrophy, accumulate volume
- If use ‘heavier’ weight (e.g. 80%+) you can use less volume
- If use lighter weight you must prescribe multiple sets to failure
Strength outcomes tend to become more pronounced in ……?
Compound movements with higher intensity
Differences in strength and hypertrophy appear to become pronounced between _____RM loading and ____RM type loading, regardless of volume differences
10-12 RM loading and 4-5RM type loading
No difference in hypertrophic outcomes between ____RM type loading
10-25RM
Does a decreased amount of rest periods increase intensity or effort?
Effort (NOT intensity)
Novice - intermediate recommendations are ____% 1RM for ______ reps
60-70% 1RM for 8-12 reps
One study shows when high volume was achieved, ____ didn’t matter as much
intensity
Intensity is important for upregulating hypertrophic mechanisms (KUMAR), BUT if you allow for ______ to become higher, intensity matters less (BURD)
volume
The rationale for volume accrual at any intensity is thought that as you get closer to 1RM, you will eventually achieve …?
Full motor unit recruitment
Motor unit recruitment is generally different between high and low intensity contractions, apart from where we ….???
increase volume and require low contraction to be performed until failure
In this case, lower intensity contractions APPEAR to achieve similar levels of central motor output to a high intensity contraction, but only…
towards the end of the contraction
Is total volume of work great in high intensities or low intensities to failure?
Still greater at high intensities
In this study, biggest predictor of failure was pain, which was higher in the …..?
Low intensity to failure group
Similar ______ outcomes between both groups
hypertrophic
In novices, if emphasis is on strength, use…?
increased intensity
In novices, if emphasis is on hypertrophy, use…?
accumulative volume
In novices, if weight is high you can ___ volume
decrease
In novices, if weight is low you can increase…
sets to failure
