CSCS Resistance Training Biomechanics 4 — Questions and Answers
Question 1: Increasing the weight on a barbell while maintaining the same bar velocity will increase which mechanical variable?
- Acceleration
- Power output (Correct answer)
- Displacement
- Velocity
Correct answer: Power output
Power equals force multiplied by velocity; increasing force (via heavier load) at the same velocity increases power output.
Question 2: Which of the following best explains why wider grip widths in the bench press shift emphasis toward the pectoralis major over the triceps?
- A wider grip increases the range of motion at the elbow joint
- A wider grip reduces the moment arm at the elbow, decreasing triceps contribution (Correct answer)
- A wider grip increases elbow flexion throughout the movement
- A wider grip eliminates anterior deltoid activation
Correct answer: A wider grip reduces the moment arm at the elbow, decreasing triceps contribution
A wider grip shortens the horizontal distance the bar travels and reduces the elbow flexion angle, thereby decreasing the moment arm at the elbow and lessening the demand on the triceps.
Question 3: What does the stretch-shortening cycle (SSC) primarily enhance in resistance and plyometric training?
- Maximum isometric force
- Concentric power output by utilizing stored elastic energy and neural potentiation (Correct answer)
- Eccentric force absorption capacity only
- Passive range of motion
Correct answer: Concentric power output by utilizing stored elastic energy and neural potentiation
The SSC couples an eccentric pre-stretch with a rapid concentric contraction, using stored elastic energy in tendons and reflexive potentiation to augment concentric power.
Question 4: Which term describes the product of a force and the perpendicular distance from the axis of rotation?
- Impulse
- Work
- Torque (Correct answer)
- Power
Correct answer: Torque
Torque (moment of force) is calculated as force multiplied by the perpendicular moment arm distance from the axis of rotation.
Question 5: During a conventional deadlift, excessive forward lean of the trunk primarily increases the demand on which muscle group?
- Hip flexors
- Knee extensors (quadriceps)
- Spinal erectors (erector spinae) (Correct answer)
- Tibialis anterior
Correct answer: Spinal erectors (erector spinae)
A more forward trunk lean increases the moment arm of the load relative to the lumbar spine, requiring the erector spinae to produce greater extensor torque.
Question 6: What is the primary biomechanical benefit of training with free weights compared to fixed-axis machines?
- Free weights eliminate the need for stabilizer muscle activation
- Free weights require the recruitment of stabilizer and synergist muscles to control movement in multiple planes (Correct answer)
- Free weights provide a consistent resistance curve throughout the range of motion
- Free weights reduce injury risk by constraining motion to a single plane
Correct answer: Free weights require the recruitment of stabilizer and synergist muscles to control movement in multiple planes
Because free weights are not guided by a track or cam, athletes must activate stabilizing and synergistic muscles to control the load across multiple planes of motion.
Question 7: The ratio of useful work output to total work input is known as:
- Mechanical efficiency (Correct answer)
- Power factor
- Torque ratio
- Velocity ratio
Correct answer: Mechanical efficiency
Mechanical efficiency describes how effectively a system converts energy input into useful work output, and in human movement it reflects metabolic cost versus external work done.
CSCS Resistance Training Biomechanics 4
Increasing the weight on a barbell while maintaining the same bar velocity will increase which mechanical variable?