KPE160: Module 3 Exam Questions with Complete Solutions 100% Solved| Grade A+
Force-Velocity Relationship and Fibre Types Different fibre types max out at different
normalized velocities. Overall effect depends on proportion of different fibre types in a muscle.
Effects of Force-Velocity Relationship For any given levels of activation and normalized
length, activated muscles are weaker when shortening and stronger when lengthening.
Effect of ACSA on Force-Length and Force-Velocity Curves Thicker muscles are stronger, but
not longer or faster.
Effect of Resting Fibre Length on Force-Length and Force-Velocity Curves Longer muscles are
longer and faster, but not stronger.
Determinants of Muscle Forces When put together, all interact. Combining force-length and
force-velocity relationships for any given level of activation yields a 3D graph of a surface.
Bones Act as levers in our chains, with their fulcrums at joints.
Tensile Forces in Linked-Segment Chains Often have to go around corners (flexion). This is
accomplished by a system of cables (muscles-tendons) and pulleys (grooves in bones, sheaths
of fascia) that serve to keep the cables in their place.
Lever A rigid long member fixed at, but free to rotate about, a fulcrum. Different classes
exist based on relative locations of effort, load, and fulcrum. We have all 3 types in our
musculo-skeletal linked-segment system.
Class 1 Lever Have the fulcrum in the middle with the effort and resistance on either side.
, Class 2 Lever Have the resistance in the middle with the effort and fulcrum on either side.
Class 3 Lever Have the effort in the middle with the fulcrum and resistance on either side.
Muscle Pulley Functions 1. Keep tendons in place.
2. Bend the line-of-force of a muscle-tendon going around a corner. Tension is constant along a
bent cable going around a pulley. The radius of the pulley determines the moment arm of the
tensile force in the cable about the centre of the pulley.
Extensor Tendons and Pulleys Extensor muscles in kinetic chains have to go the long way
around the convex side of a flexed joint. Tendons are kept in place and re-routed (bent) by
extension pulleys (bone grooves, fascia).
Knee Extensor Pulley The trochlea (groove) in the front of the femur keeps the tendon and
kneecap in place.
Flexor Tendons and Pulleys Flexor muscles in kinetic chains go the short way across a flexed
joint. Tendons (cables) may be kept in place by flexion pulleys (fascial slings or retinacula). The
need for a flexion pulley depends on geometry.
Retinacula at the Wrist True flexion pulleys in that they hold the tendons in place during
bending of the wrist - dorsal flexion (extension) and ventral flexion (flexion).
Retinacula at the Ankle The extensor retinaculum is actually a dorsi-flexion pulley, while the
peroneal retinacula are actually extension (plantar-flexion) pulleys, and there is a groove in the
back of the fibula for these extensor tendons.
Retinacula A band of thickened deep fascia around tendons that holds them in place.
Force-Velocity Relationship and Fibre Types Different fibre types max out at different
normalized velocities. Overall effect depends on proportion of different fibre types in a muscle.
Effects of Force-Velocity Relationship For any given levels of activation and normalized
length, activated muscles are weaker when shortening and stronger when lengthening.
Effect of ACSA on Force-Length and Force-Velocity Curves Thicker muscles are stronger, but
not longer or faster.
Effect of Resting Fibre Length on Force-Length and Force-Velocity Curves Longer muscles are
longer and faster, but not stronger.
Determinants of Muscle Forces When put together, all interact. Combining force-length and
force-velocity relationships for any given level of activation yields a 3D graph of a surface.
Bones Act as levers in our chains, with their fulcrums at joints.
Tensile Forces in Linked-Segment Chains Often have to go around corners (flexion). This is
accomplished by a system of cables (muscles-tendons) and pulleys (grooves in bones, sheaths
of fascia) that serve to keep the cables in their place.
Lever A rigid long member fixed at, but free to rotate about, a fulcrum. Different classes
exist based on relative locations of effort, load, and fulcrum. We have all 3 types in our
musculo-skeletal linked-segment system.
Class 1 Lever Have the fulcrum in the middle with the effort and resistance on either side.
, Class 2 Lever Have the resistance in the middle with the effort and fulcrum on either side.
Class 3 Lever Have the effort in the middle with the fulcrum and resistance on either side.
Muscle Pulley Functions 1. Keep tendons in place.
2. Bend the line-of-force of a muscle-tendon going around a corner. Tension is constant along a
bent cable going around a pulley. The radius of the pulley determines the moment arm of the
tensile force in the cable about the centre of the pulley.
Extensor Tendons and Pulleys Extensor muscles in kinetic chains have to go the long way
around the convex side of a flexed joint. Tendons are kept in place and re-routed (bent) by
extension pulleys (bone grooves, fascia).
Knee Extensor Pulley The trochlea (groove) in the front of the femur keeps the tendon and
kneecap in place.
Flexor Tendons and Pulleys Flexor muscles in kinetic chains go the short way across a flexed
joint. Tendons (cables) may be kept in place by flexion pulleys (fascial slings or retinacula). The
need for a flexion pulley depends on geometry.
Retinacula at the Wrist True flexion pulleys in that they hold the tendons in place during
bending of the wrist - dorsal flexion (extension) and ventral flexion (flexion).
Retinacula at the Ankle The extensor retinaculum is actually a dorsi-flexion pulley, while the
peroneal retinacula are actually extension (plantar-flexion) pulleys, and there is a groove in the
back of the fibula for these extensor tendons.
Retinacula A band of thickened deep fascia around tendons that holds them in place.
