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Lecture

KINE 1020 Lecture Notes - Headache, Dizziness, Oligomenorrhea


Department
Kinesiology & Health Science
Course Code
KINE 1020
Professor
Jennifer Kuk

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January 4 th
Lecture Topic 4
Why is strength important
Performance related
- Sport
Greater power, speed, balance
Reduce demands on cardio
- Job/occupational requirements
Reduced risk of injury
Productivity
Health Related
- Lower risk of functional limitations
Avoid injuries
Predicts advanced age disability
Reduces chronic low back pain
- Lower risk of chronic diseases
Improved blood sugar control
Prevents osteoporosis
- Psychological health
Improved self-image
- Emergencies
Endurance – type 1 muscle fibre higher %, low type 2 %
Power – type 2 muscle fibre higher %, low type 1 %
Best to have range of fibres, but affects type of sport you do
Fibre type proportion related to type of activity (endurance/power)
Winning not predicted by muscle fibres (can be small range difference) 80%
outperform 85%

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Health Related (2)
Lowering the risk of functional limitations
- Maintaining or improving muscular strength later in life reduces the percentage of
functional limitations over 50% for both men/woman
Muscle strength across the lifespan (static, dynamic, pull strength and muscular endurance)
Paediatric years – childhood to young adult
Elderly
** If you train as young adult, relatively maintain strength through old age** (does
decrease)
Decreasing muscle strength with aging
Sarcopenia: loss of muscle mass and strength due to aging
- 1-2% muscle mass per year past 50 yrs of age – loss of strength varies/ may be greater
Prevalence
- Impacts 10-25% of the population under age 70 and 40% above age 80
- By 80 yrs a loss of 30-40% of muscle fivers (hypoplasia of muscles containing type II
muscle fibers.
Concerns
- Risk of functional limitations
** Sarcopenia is a result of programmed cell death- apoptosis
Characterized by:
- DNA fragmentation
- Nuclear condensation leading to formation of apoptotic bodies (engulfed by macrophages
but do not induce an inflammatory response)
- Cell shrinks when near apoptosis
January 6 th
Lecture Topic 4 continued
DNA fragmentation
- 2 main proteins
DFF 40 (DNA fragmenting factor 40) – degrades/fragments the DNA

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DFF 45 (DNA fragmenting factor 45) – inhibits DFF40
DFF45 changed DFF40 active = DNA fragmentation
-Casp-3 (Caspase 3) enzyme activated during apoptosis
Nuclear condensation or Disassembly
Uncondensed ring Necklace Collapse/ Disassembly
Decreasing Muscle Strength with Aging
Potential causes of Sarcopenia (still being identified)
1. Activation of apoptotic pathways – caspases (enzymes that breakdown and degrade
proteins and DNA) and AIF
2. Loss or hormonal adaptations (decrease in testosterone and growth hormone)
3. Loss of neurological influences (selective loss of type II motor units resulting in cluster of
type I muscle fibre with age)
Apoptotic pathways lead to programmed cell death
Inactive Active
Caspase-Dependent Processes
Procaspases (inactive) Caspase’s (active) DNA / Protein
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