Adaptions to Strength and Power Training Flashcards
Progressive hypertrophy, as reported by Narici et al., (1996) reported what differences to isometric strength and ACSA with 6 months of strength training?
Rapid gains in strength in the early period of programme. Strength gains do continue but at a much slower rate.
ACSA is a linear steady progression throughout programme
Morphological adaptation is more noticeable in the first few months.
What were the findings of Erskine et al., (2014) investigating the contribution of hypertrophy to individual strength changes?
MVF and 1RM were both show to moderately correlated with changes in muscle volume
r= 0.5
What findings did Balshaw et al., (2017) reported when measuring muscle volume, pre strength and neural activation factors associated with individual strength changes after RT?
1) bigger changes in muscle volume elicited bigger changes in strength
2) Those who were able to achieve greater changes to neural activation had greater strength gains
3) people who started at a lower level improve more than those with more strength pre training.
The biggest predictor variable was the change in EMG
What is regional hypertrophy?
Changes in ACSA, measured at different levels along the quad muscles, occur at different rates and sizes relative to the area of the muscle measured.
Some parts of a muscle are loaded more than other. These overloaded areas will adapt and grow more than other parts
What were the findings of Aagaard et al., (2001) measuring changes in angle of pennation pre and post 14 weeks of ST?
Increase in the angle of pennation such that the average is high post training.
25% increase on a group level
optimal angle of pennation for isometric strength is 45 degrees. This is a move toward to optimal angle
What were the findings of Reeves et al., (2009) comparing changes to muscle architecture following 14 weeks of conventional or eccentric training?
(methods: 14 weeks, 80% of 5RM; eccentric load 50% increase from conventional training.
Fascicle length significantly increased post training in Eccentric group
Pennation angle significantly post training in conventional training group
Eccentric training more optimal for increasing velocity
Conventional training more optimal for increasing maximal strength
What were the findings of MacDougall et al., (1984) when determining if changes in CSA were attributable to hypertrophy or hyperplasia?
What were the correlation figures?
Fibre hypertrophy is more related to increase in CSA than hyperplasia.
Correlation figures:
Hypertrophy= 0.7
Hyperplasia= 0.3
How does one calculate number of muscle fibres?
csa/fibre size
According to Aagaard et al., (2001), what muscle fibres preferentially hypertrophy following 14 weeks of ST?
What were the % changes in fibre types in this study?
Type 1 fibres increased by 8%
Type 2 fibres increased by 18%
Following short term training, preferential hypertrophy occurs in type 2 fibres
What findings did Anderson & Aagaard et al., (2000) reported when looking at the shifting of muscle fibre types following 3 months of RT and 3 months of detraining?
Type 1 fibres do not change significantly
Increase in type 2a muscle fibres because of a decrease in 2x fibres.
There is a shift from 2x to 2a muscle fibre types following RT
following detraining, 2x fibres bounce back to a greater level- 2x overshoot
MacDougal et al., 1986 reported what findings when investigating changes within a muscle fibre following 6 months of RT
a 31% increase in fibre size was reported.
16% of this increase was attributed to size of the myofibrils. Some evidence for increase number of myofibrils
Thus, growth and proliferation of of myofibrils appear to account for fibre hypertrophy
Describe the Goldspink et al theory by which myofibrillar proliferation occurs?
As muscle grows, peripheral contractile filaments are added to the myofibril
As Z line is a narrowing of the myofirbil, the added peripheral filaments are pulled obliquely, this can apply forces to the Z line. As the myofibril grows this causes a rupture.
This enables two new myofibrils to be formed
What is muscle protein synthesis and muscle protein breakdown?
MPS is where more proteins are made than are broken down- net gain is muscle mass
MPB is the opposite of MPS- net loss in muscle mass
How is protein manufactured?
Proteins are made via the transcript and coding of DNA
DNA contains the instructions for the manufacture of proteins
DNA is found within the nucleus of the cell. Protein instructions are transcripted onto messenger RNA, that leaves nucleus and enters cytoplasm
mRNA then enters translation and becomes new protein
Welle et al., (1999) found that stimulation of MPS post exercise is mediated by what?
Haddad et al., (2005) also found these results.
23hr post exercise, MPS was acutely upregulated by 30%
mRNA for myosin heavy chain and actin mRNA does change per tissue mass. No increase in transcription.
Thus, MPS must be stimulated by a more efficient translation of mRNA
