Question

1. To stretch the quadriceps using the PNF technique,

a.) contract the quadriceps to activate the GTO, causing a reflex contraction of the hamstrings; then stretch the quadriceps.

b.) contract the quadriceps to activate the GTO, causing a reflex relaxation of the quadriceps; then stretch the quadriceps.

c.) contract the quadriceps to activate the muscle spindle, causing a reflex relaxation of the quadriceps; then stretch the quadriceps.

d.) stretch the quadriceps ballistically to activate the muscle spindle, causing a reflex relaxation of the quadriceps for a greater stretch.

2. Vital capacity is the sum of which volumes or capacities?

a.) Inspiratory Capacity + Expiratory Reserve Volume

b.) Maximal Breathing Capacity + Residual Volume

c.) Tidal volume + Inspiratory Reserve Volume

d.) Tidal Volume + Expiratory Reserve Volume + Residual Volume

3. If the predicted residual volume (e.g., calculated from age and height) is less than the actual residual volume (e.g., determined by oxygen dilution), what effect will this have on body fat percentage obtained by hydrostatic weighing?

Link to Body Density Formula:  

Db formula - hydrostatic weighing.docx

If the link doesn't open, the formula for Db is:

Numerator: Body Weight

Denominator: { [Body Weight - Submerged Weight]/Density of Water} - RV + 0.1 L

a.) Body fat percentage will be overestimated.

b.) No effect on calculated body fat percentage

c.) Body fat percentage will be underestimated.

d.) Body fat percentage will be overestimated in women and underestimated in men.

Answer 1

1)Proprioceptive neuromuscular facilitation(PNF) stretching is an effective way to increase the range of a motion.In this method instead of stretching the muscle, first contraction of muscle is done and hold.This creates a reflex relaxation called autogenic inhibition,which helps further relaxation.Then a deeper stretch can be made.There are two neurophysiologic sensory receptors involved with the reflex.They are Golgi Tendon Organs(GOT) and muscle spindle.Stimulating GTO causes autogenic inhibition.The muscle spindles is activated when a muscle is stretched causing a contraction.So to stretch the quadriceps using the PNF technique,b.) contract the quadriceps to activate the GTO, causing a reflex relaxation of the quadriceps; then stretch the quadriceps.

2)Human lung size depends on gender height and genetics.An average lung is found to hols a maximum of 6 liters of air.The lung volumes and capacities are measured using various parameters.Tidal volume is the air that is inhaled in a breath when breathing normally.Expiratory reserve volume or ERV is the volume of air that one can exhale after a normal exhalation.Inspiratory reserve volume is the is the volume of air that one can inhale after a normal inhalation.Residual volume is the volume of air left in the lungs after a forced exhalation.Vital capacity is defined as the maximum air that can be moved in or out of the lungs in a respiratory cycle.This is a sum of Tidal Volume + Expiratory Reserve Volume + Residual Volume.

3)Hydrostatic volme is weighing underwater to calculate the density of a body.The calculation of residual volume have great importance during hydrostatic weighing.If error occurs than actual RV then the fat percentage calculated can differ.If RV is estimated less than actual RV then Body fat percentage will be overestimated in women and underestimated in men.