Sprint interval training - Septo et al (1999)
- Varied number of bouts, duration of work (30s-8min), intensity and rest intervals
- Short sprint interval training enhanced 40km TT performance
- Also improved peak power and sprint power
Sprint interval training - Gabala et al (2006)
- Compared 4x6 30s (sprint) to 90-120 mins at 65% Vo2max continuous training
- 750kJ TT improved with sprint interval training
- Improved muscle buffering capacity with sprint interval training
Hostrup and Bangsbo (2017)
- Review of papers on sprint interval training
- Mainly in trained athletes
- Effect size ranges form 6-27% performance improvement (it works)
Explain acton potential process
- Action potential generated at NJ, propagates across sarcolemma
- Sodium ions go into the cell, potassium ions leave the cell to depolarise membrane
- Depolarisation releases calcium from SR into the cell
- Calcium release triggers muscle contraction
- Calcium then taken back up into SR, muscle membrane repolarises to allow action potential
If this process is impaired, muscle contraction is impaired
Consequences of high intensity exercise:
- Increase ATP turnover
- Increased rates of glycolytic flux
- Increased rates of H+ accumulation
- Increased rates of lactate accumulation
Repeated sprint training - Bishop et al (2011)
- Monocarboxylate transporter is responsible for co-transporting H+ and lactate out of the cell
- Increase in monocarboxylate after repeated sprint exercise
Repeated sprint training - Neilson et al (2004)
- H+ activates a potassium channel that removes potassium from the cell
- Extracellular potassium associated with fatigue
- Repeated sprint interval training reduced extracellular potassium build up
Increased strength - Folland and Williams (2007)
- 6 months of strength training = increase in strength
- Increase in muscle size was correlated with increase in strength
Protein synthesis rates - Phillips et al (1997)
- Maximum resistance exercise session
- Fractional synthetic rate (FSR) was directly proportional to synthesis of proteins
- Increase FSR following resistance training is maintained for 24hrs
- Increase MPS is greater than MBS - meaning muscles get bigger
How does resistance training tip the balance?
Muscle tissue synthesised per day:
- 1-2%
After resistance exercise:
- 2-3% (600-900g)
Myonucleur Domain Theory
- A growing muscle fibre requires increase number of myonuclei to sustain cellular control
- Each area that the satellite cell controls post adaptation, needs to be the same as pre-adaptation
- Increasing satellite cells helps increase the number of myonuclei
Selective hypertrophy of type II cells - D’Antona et al (2006)
- Taken muscle fibres from the quadriceps of control vs bodybuilders
- Greater number of type IIx in bodybuilders
- Type IIx had greater cross-sectional area in bodybuilders
- When training stops - greater decrease in type IIx fibres
Weak correlation between muscle cross-sectional area and strength (Maughan et al, 1983)
3 athletes with different cross-sectional area all produced similar cycling performance
- muscle cross-sectional area and strength have a weak correlation
- Due to the muscle quality, fat content, neuromuscular recruitment and training/experience
Type of training (Compos et al, 2002)
- Low rep = 3-5 x 4 sets
- Int rep = 9-11 x 3 sets
- High rep - 20-28 x 2 sets
All marched for work done - Low rep produced greatest increase in 1 RM (strength)
MPS and resistance training - Kumar et al (2009)
- MPS maximised at >75% 1RM
- Increasing volume does not further increase MPS
Concurrent training - Coffey and Hawley, (2016)
- In trained individuals, both endurance and resistance training interfere with each other
- Sprint training >4 days per week or exercising at >80%1RM impairs strength and muscle mass gains
Explain about the mTOR pathway
- Resistance exercise activates mTOR pathway in order to increase MPS and hypertrophy
- In endurance training, PGC1-Alpha increases mitochondrial content
- In endurance training we activate AMPkinase, when we break down ATP this generates AMP, which is a stressor to the muscle and therefore activate AMPkinase which inhibits mTOR
- Therefore, endurance exercise inhibits resistance training
Delayed onset muscle soreness - Lauritzen et al (2009)
- ECC training causes micro damage to the muscle fibre during the lengthen process
- The remodelling process of the tissue to strengthen the sarcomere structure could cause the muscle soreness
Benefits of Eccentric training - (Vogt and Hoppeler, 2014)
- ECC more efficient at increasing strength vs OCN
- Increased muscle mass in ECC v CON - increases FT IIa and IIx CSA
- Superiority of ECC possibly due to increase RFD
