Muscle Damage and Adaptions Joe Flashcards
DOMS definition and etiology
Delayed onset of muscular soreness
A broad term used to describe muscular stiffness, tenderness or damage after high intensity, eccentric or unaccustomed exercise
EIMD definition and etiology
Exercised Induced Muscle damage is caused by unaccustomed exercise commonly involving large amounts of eccentric contractions
Sports that commonly cause EIMD
Contact sports Weight lifting (overload) Military training Unaccustomed exercise Muscle imbalances
Impacts of EIMD
Decrease in:
- Muscle strength and power: 1-12h
- Proprioceptive activity
- Athletic performance
- Range of Movement
Increase in: - Acute inflammation: 1-12h - Chronic inflammation: 5-7 days -Creatine kinase: 5-7 days - Muscle soreness: 24-48h -Swelling -Stiffness -Sensitivity to movement Vo2 during exercise RBE during exercise
EIMD on force generation
Force generation capacity after mild EIMD:
- Reduced by 15% immediately
- 5% 1-24h
Force generation capacity after severe EIMD:
- 50% immediately
- 35% 1-72h
Measures of EIMD
Direct:
- Magnetic Resonance Imaging scan
- Muscle biopsy
Indirect:
- Blood samples
- Rate own pain chart
- Ultrasound
- Maximum voluntary contraction
Repeated bout effect definition:
A single bout of exercise can protect skeletal muscle from damage during a subsequent bout of eccentric exercise via attenuation to damage.
RBE= a reduction in muscle damage and can last several weeks to 6 months
RBE Muthalib et al
2011
1) Initial bout
2) Adaptions:
Neural: Nervous system changes
Connective tissue: increased intramuscular connective tissue
Cell theory: Cell changes protect muscle fibres and improve strength
3) Repeated bout
4) Reduced muscle damage
4 stages of the training recovery cycle
- Overload: Fatigue increases and peaks
- Restoration: Fatigue falls over 24h
- Adaptions: Occur 24-72h
- Reversal: Adaptions last no longer than 72h
Recovery enhancement
Graph:
Adaptions from RBE: Neural
Shift in motor neuron recruitment
Increase in a-motoneuron excitability
Increased inhibitory feedback
Adaptions from RBE: Inflammation
Increased sensitivity
Adaptions from RBE: Muscle-tendon adaptions
- Reduced fascile elongation
- Increased tendon compliance
- Smaller displacement of myotendinous junction
Adaptions from RBE: ECM Remodelling
Extracellular matrix (ECM)
- Initial ECM deadhesion
- Delayed ECK adhesion and collagen expression
