Delayed Onset Muscle Soreness Flashcards
What is Delayed Onset Muscle Soreness?
Muscle soreness that occurs 24-72hrs after exercise
What are the prevailing theories for the cause of DOMS?
- Lactate accumulation/decreased pH
- Muscle Spasm
- Muscle Damage
What evidence is there that muscle damage is the cause of DOMS?
Muscle biopsy after eccentric exercise shows swelling, and decreased protein stained, meaning breakdown and escape of that protein
What can electron microscopy show us about muscle damage and DOMS?
Z-Band streaming is seen in muscles with DOMS; the sarcomeres are disrupted, or not intact at all
Explain increases in myoglobin and creatine kinase after exercise
Myoglobin peaks after 1 hour, then decreases to almost baseline after 72hr. Creatine Kinase increases until peak at 24 hours then slightly decreases by 72hrs
What can be done apart from invasive muscle biopsies to measure muscle damage?
Measure myoglobin and creatine kinase in the blood
With reference, What impact does muscle damage have on muscle function?
Clarkson et al 1992 found that extreme DOMS/muscle damage decreased maximal strength for over 10 days after exercise. Betts et al 2009 found the same effect for 7 days
With reference, what impact does muscle damage/DOMS have on motor skills?
Pearce et al 1998 found that DOMS limited the ability of an individual to follow a tracking cursor task, and got worse even with practice over the first few days
With reference, what impact does muscle damage/DOMS have on muscle glycogen?
Costill et al 1990 found that muscle glycogen concentrations did not increase to pre exercise levels 24hrs after exercise, and even decreased after 72hrs
Why does muscle damage/DOMS limit muscle glycogen?
White blood cells that have invaded the cell to heal it are taking up glucose
The architecture of the muscle is not able to hold as much glycogen due to damage
summarise the consequences of muscle damage/DOMS
- Soreness
- Decreased force production capability
- Decreased skill
- Decreased glycogen stores
What is Exertional Rhabdomyolysis?
Excessive protein breakdown from muscle damage entering the blood, over straining the kidneys trying to remove all the protein from the blood
What are the symptoms of Exertional Rhabdomyolysis?
- dark Cola coloured urine
- swelling around the abdomen
- pain in the muscles
What can cause muscle damage?
- Eccentric muscle actions
- Calcium activated proteases?
- Hyperthermia?
- Free radicals?
- Novel stimuli/sudden increase in training load after being sedentary
Why does eccentric muscle action cause muscle damage?
- High forces?
- Lower fibre recruitment?
- Lengthening action?
