Int. Journal of Sports Science & Coaching · 2024 · Research Note

Feedback Type &
Vertical Jump Testing
in NCAA Basketball

Does showing athletes a team leaderboard during CMJ testing change how they jump — and how consistently they jump? Comparing individual visual feedback (IVF) to social comparison feedback (SCF) across 29 NCAA Division-I basketball players over a 6–8 week in-season period.

29NCAA D-I Athletes
7/8Metrics Better in SCF
6/7Metrics More Stable in SCF
~8.4%Barbell Velocity Gain w/ Feedback
01 Study Design & Conditions
Condition 1
IVF — Individual Visual Feedback

Athletes received immediate feedback on their own jump height on a small tablet placed directly in front of them. No other team members could see the display. Standard setup, as commonly used in most sport science monitoring contexts.

• Private tablet display only  • Individual score visible  • No team context
Condition 2
SCF — Social Comparison Feedback

Athletes received feedback on their tablet plus a large team leaderboard on a TV screen visible to all athletes and coaches. The leaderboard showed performance rankings and individual jump scores for the entire team in real time, introducing social comparison and competition dynamics.

• Private tablet + team TV screen  • Ranked leaderboard  • Full team + coaches can see
Study setup: 17 male (age 20.5±1.5 yrs, height 199.3±9.9 cm, mass 93.2±10.8 kg) and 12 female (age 20.8±1.3 yrs, height 183.8±9.1 cm, mass 77.6±12.1 kg) NCAA Division-I basketball players. Athletes performed 3 CMJ trials at the start of strength & conditioning sessions over 6–8 in-season weeks, with IVF and SCF sessions randomised (3–4 each). Athletes were not told the purpose of the two conditions. Hawkin Dynamics dual force plates, 1,000 Hz, hands on hips.
02 Performance Results — IVF vs. SCF
Raincloud plots IVF vs SCF
Figure 1

Raincloud plots comparing IVF vs. SCF conditions for 6 significant CMJ metrics. Pink circles = female athletes; blue circles = male athletes. Black density distributions = SCF; grey = IVF. In all cases SCF showed significantly higher performance. ***p < 0.001, **p < 0.01.

Between-Condition Comparisons — Means, Effect Sizes & Practical Significance Mixed Effects Model
Metric
IVF
SCF
ES
>SEM?
Jump Height
37.1±1.75 cm
39.1±1.85 cm*
0.20
Yes ✓
mRSI
0.54±0.03
0.58±0.03*
0.25
No
Avg Braking Velocity
0.84±0.02 m/s
0.88±0.02 m/s*
0.32
= SEM
Braking Net Impulse
113±5.13 N·s
119±5.49 N·s*
0.18
No
Propulsive Net Impulse
231±9.51 N·s
236±9.68 N·s*
0.10
Yes ✓
Countermovement Depth
27.3±0.91 cm
28.2±1.07 cm*
0.14
No
Time-to-Takeoff
0.70±0.01 s
0.68±0.02 s*
0.18
No
* = statistically significant (p ≤ 0.05) · ES interpreted per multilevel model guidelines · Yes ✓ = between-condition difference exceeded average within-session SEM (practically meaningful)
Key performance interpretation: While SCF was statistically superior for 7/8 metrics, effect sizes were universally small (ES 0.10–0.32). Only jump height and propulsive net impulse showed differences exceeding the SEM — the only two with practical significance. Average braking velocity was equal to the SEM. This means that for most metrics, SCF is statistically better but coaches should not overinterpret the magnitude. The metrics most responsive to SCF were mRSI and average braking velocity, hypothesized to reflect faster descents and greater intent in the countermovement.
03 Sex × Feedback Interaction
⚠️
mRSI Only
The only metric showing a significant sex × feedback interaction (F=6.34, p=0.020). Men’s mRSI was significantly higher in SCF vs. IVF; women’s mRSI was not significantly different between conditions.
👪
Men > Women
Male athletes appear more responsive to the competitive leaderboard context in terms of their jump strategy (time-to-takeoff component of mRSI). This may reflect differences in ego orientation or competitiveness responses.
📋
Caution
Do not generalise these findings across sexes without verification. Sport scientists should assess sex-specific responses when implementing SCF in mixed or single-sex programs. Upward social comparisons can also increase shame in sport.
04 Intra-Day Variability & Data Stability
CV density plots by feedback condition
Figure 2

Metric-specific density plots of intra-day coefficient of variation (CV%) by feedback condition. Blue = IVF; grey = SCF. The dashed vertical line = CV of 10% (commonly accepted cutoff for good relative variability). SCF distributions are consistently tighter (left-shifted), indicating less within-session variability.

CV Ratio (IVF ÷ SCF) — Critical Threshold > 1.15 All Ratios >1 = SCF More Stable
Propulsive Net Impulse
1.34
Time-to-Takeoff
1.24
Jump Height
1.23
Avg Braking Velocity
1.16
Braking Net Impulse
1.16
mRSI
1.17
Countermovement Depth
1.04
★ = CV ratio exceeds critical threshold of 1.15 · Countermovement depth was the only metric NOT meeting this threshold.
Why this matters more than the performance difference: More stable data means the sport scientist can detect smaller, real changes over time. If SCF consistently produces tighter CV distributions, then seasonal monitoring or fatigue detection becomes more sensitive — potentially the more important finding for practitioners.
05 Athlete-Specific Responses
Athlete-specific random intercepts and slope coefficients
Figure 3

Left: Athlete-specific random intercepts for jump height compared to the sample mean (±1 SD, grey band). Shows the natural between-athlete spread in jump ability. Right: Athlete-specific slope coefficients showing how much each athlete’s jump height changed between IVF and SCF conditions compared to the average within-session SEM (grey band). Most athletes showed a positive SCF response, but the magnitude varied considerably.

What the Intercept Plot Tells Coaches

The left plot shows each athlete’s baseline jump height relative to the team average. Athletes whose bars fall within the grey band are near the team mean. Bars extending beyond show above- or below-average jumpers. Random component ICC (ICCR) = 0.95, meaning 95% of variance in jump height was due to differences between athletes — far more than the feedback condition itself.

This is a critical reminder: athlete identity is the dominant driver of jump performance, not feedback type.

What the Slope Plot Tells Coaches

The right plot shows the athlete-specific SCF benefit — how much each individual improved during SCF vs. IVF, relative to the average SEM band. Athletes whose bars extend beyond the grey band showed a response exceeding typical noise.

Coaching application: Some athletes are much more responsive to the competitive leaderboard than others. Coaches can use this to identify who benefits most from SCF and who performs consistently regardless of context.

06 Practical Takeaways for Sport Scientists & Coaches

① Be consistent with your feedback type. Mixing IVF and SCF sessions across time will inflate data variability and reduce the sensitivity of your longitudinal monitoring. Pick one approach and stick with it — do not implement feedback conditions randomly.

② Use SCF to maximise intent on test days. If the goal is to elicit peak performance (e.g., pre-season profiling, return-to-play clearance), the leaderboard condition will systematically produce higher jump outputs with more consistent data. However, be mindful of the psychological context — rank-based SCF can also increase shame if not framed around effort and improvement.

③ SCF produces more stable data — especially for monitoring. For longitudinal monitoring applications (fatigue tracking, season trends), SCF may be the preferred condition because tighter within-session CVs mean smaller genuine changes are detectable. The monitoring use case may benefit more than the profiling use case.

④ Account for sex differences in feedback response. mRSI showed a significant sex × condition interaction — men benefited more from SCF than women. Coaches should not assume feedback affects both groups identically, especially for jump strategy metrics.

⑤ Statistical vs. practical significance — use both lenses. Seven metrics were statistically significant, but only jump height and propulsive net impulse exceeded the SEM (practically meaningful). When athletes ask “was my jump actually better?”, the SEM comparison is the honest answer — not the p-value.