CSCS Technology & Digital Tools 3 — Questions and Answers
Question 1: When an athlete performs a countermovement jump (CMJ) on a force plate, the device primarily records:
- Muscle fiber cross-sectional area changes
- Ground reaction forces, from which jump height and power can be derived (Correct answer)
- Blood lactate accumulation during the concentric phase
- VO2 kinetics and oxygen debt following the jump
Correct answer: Ground reaction forces, from which jump height and power can be derived
Force plates measure vertical (and horizontal) ground reaction forces over time, enabling calculation of impulse, jump height, power, and rate of force development.
Question 2: The reactive strength index (RSI) is calculated as:
- Peak force divided by body mass
- Rate of force development measured at the 200-millisecond mark
- Jump height divided by ground contact time (Correct answer)
- Impulse divided by total ground contact duration
Correct answer: Jump height divided by ground contact time
RSI = jump height / ground contact time, quantifying an athlete's ability to rapidly absorb and redirect force during stretch-shortening cycle tasks like drop jumps.
Question 3: Electromyography (EMG) in sport science primarily quantifies:
- Electrical activity generated by contracting skeletal muscle (Correct answer)
- Oxygen consumption rate during resistance exercise
- Joint angles and segment kinematics during movement
- Tendon and connective tissue stiffness under load
Correct answer: Electrical activity generated by contracting skeletal muscle
EMG detects the electrical signals produced by motor unit activation in muscle, enabling assessment of muscle onset timing, activation level, and fatigue.
Question 4: A 3D motion capture system using retroreflective markers is primarily used to obtain:
- Ground reaction force magnitudes during athletic movements
- Cardiovascular response patterns to incremental exercise
- Three-dimensional kinematics of body segments and joint angles (Correct answer)
- Sleep architecture and movement patterns during overnight recovery
Correct answer: Three-dimensional kinematics of body segments and joint angles
Retroreflective marker-based systems (e.g., Vicon, Motion Analysis) track marker positions in 3D space to calculate joint angles, segment velocities, and movement patterns.
Question 5: Which force plate variable is widely considered the most sensitive indicator of acute neuromuscular fatigue?
- Static body weight measured at session start
- Peak landing force during a drop landing task
- Rate of force development (RFD) or CMJ flight time (Correct answer)
- Average force during the eccentric loading phase
Correct answer: Rate of force development (RFD) or CMJ flight time
RFD and CMJ flight time are highly sensitive to neuromuscular fatigue because explosive force expression declines before peak force is noticeably affected.
Question 6: The primary practical advantage of markerless motion capture over traditional marker-based systems is:
- Substantially greater accuracy in joint moment calculations
- Reduced setup time and no need to attach markers to the athlete (Correct answer)
- Lower equipment cost combined with direct force measurement capability
- Superior ground reaction force estimation during dynamic tasks
Correct answer: Reduced setup time and no need to attach markers to the athlete
Markerless systems use depth cameras or AI pose estimation to track body segments without physical markers, dramatically cutting preparation time in applied sport settings.
Question 7: The free video analysis software Kinovea is primarily used in sport science for:
- Managing team scheduling and session attendance records
- Running inferential statistical analyses on group performance data
- 2D video-based motion analysis including angle measurement and tracking (Correct answer)
- Creating GPS-based heat maps of player movement during competition
Correct answer: 2D video-based motion analysis including angle measurement and tracking
Kinovea allows coaches and practitioners to measure angles, draw reference lines, slow footage, and compare movements frame-by-frame directly from video.
CSCS Technology & Digital Tools 3
When an athlete performs a countermovement jump (CMJ) on a force plate, the device primarily records: