Performance Calculators

What counts as a "submaximal" jump. Perform three counter-movement jumps (CMJ) at about 80–90% of perceived effort with 60–90 seconds of rest between attempts. Don't pre-load or pause at the bottom — let it flow. The calculator works whether you use a Vertec, contact mat, or jump rope laid on the wall; what matters is the best of three at submax.

Why we average then adjust. Averaging smooths out single-trial noise. The training-age multiplier reflects that beginners tend to under-perform on max efforts due to unfamiliarity with high-output jumping, while advanced athletes are closer to their submax ceiling. The formula:

Max Vertical ≈ Average Submax × Training Multiplier
Peak Power (Lewis) ≈ √(4.9 × body_mass × jump_height × 9.81)
Peak Power (Harman) ≈ 60.7 × jump_height(cm) + 48.7 × body_mass(kg) − 1307

What this does NOT measure. Approach jump (running) is a different test — it adds horizontal-to-vertical conversion and is typically 8–15 cm higher than a CMJ in trained players. Don't compare this projection to your dunk approach jump. It also won't reflect a player with a heavy strength bias; if you squat 2× bodyweight but your vertical is "only" projected at 60 cm, the discrepancy is in the strength-power transfer, which this tool is not built to diagnose.

How often to re-test. Every 6–8 weeks, ideally at the same time of day. Vertical fluctuates 2–4 cm with sleep, fatigue, and warm-up quality.

Can I just put my actual max in? You can — set all three submax fields to the same value. The training multiplier will still apply, but it'll mostly cancel out at the advanced/elite levels.

Why are my Lewis and Harman peak powers different? They use different biomechanical assumptions. Lewis assumes the entire jump is vertical and ignores body position at landing; Harman was calibrated against force plate data on counter-movement jumps. The two should agree within ±10% in a healthy athlete — large discrepancies usually signal measurement error.

Is this safe for under-16 players? The projection logic is fine. The CMJ test is widely used in youth basketball screening. For pubertal athletes, vertical norms are very different — use position-specific norms (e.g., NBA Combine averages) only as a loose reference, not a target.

Why we show both %HRmax and HRR-based zones. %HRmax is simpler but assumes a linear response from rest to max. Heart Rate Reserve (HRR = max − resting) better captures sub-max work. The HRR column is what you'd actually target on a chest strap; the %HRmax column is what most fitness watches and gym equipment display.

Typical basketball session targets. A conditioning session should bias Zone 4 (84–94% HRmax) for repeated high-intensity efforts with partial rest — that's what games actually look like. Zone 5 is reserved for transition work, finishing drills, and short-burst conditioning. Zone 2 is for warm-up, cool-down, and active recovery between heavy sessions.

Caveats. Max HR varies ±10 bpm between individuals with the same age. If you have access to a recent lab test or a well-conducted field test (e.g., 3×3-minute max efforts with 2-min rest, peak HR of the day), override the Tanaka estimate. Don't override on a single max sprint — under-motivated efforts underestimate max HR by 3–8 bpm.

How to read the chart. Lower bound is the floor; upper bound is the ceiling. Most sessions should target the middle of the zone, not the upper bound. Sustained work at the upper bound of Zone 4 is essentially interval training.

Should I be in Zone 4 every practice? No — that's over-reaching. A weekly mix of 1–2 Zone 4-dominant sessions, 2 Zone 3-dominant sessions, and 1 Zone 2 recovery session is a reasonable starting template. Adjust based on game schedule and soreness.

Why does my watch say a different max HR? Wrist optical sensors are noisier than chest straps, especially during high-intensity interval work. A 3–7 bpm discrepancy is normal. Trust the chest strap; if you only have a wrist sensor, take a 30-day median of "max HR observed" instead of the daily peak.

Does caffeine change the zones? Caffeine raises resting HR but doesn't shift your true max HR meaningfully. If your resting HR is artificially high (caffeine, dehydration, illness), the HRR-based zone will be slightly off. Use %HRmax instead that day.

The 2011 Compendium of Physical Activities lists basketball at 8.0 METs. That's a generic estimate. Position-specific studies using GPS tracking (e.g., NBA SportVU data) and accelerometry show:

• Point guards: 8.0–8.5 METs (constant movement, frequent direction changes)
• Wings / combo guards: 7.5–8.0 METs (high-intensity bursts, less total distance)
• Forwards: 7.0–7.5 METs (less perimeter running, more close-range contact)
• Centers / traditional 5s: 6.5–7.0 METs (lowest total work but highest peak efforts)

Team pace is the single biggest non-position lever. A team at 90 possessions per 48 min produces ~10% less energy demand than a team at 105. Playoff basketball adds another 5–10% due to defensive intensity.

The formula:

kcal = MET × body_mass(kg) × duration(h) × intensity_multiplier

Carbohydrate recommendation follows the 1.0–1.2 g/kg/hour post-exercise window for the first 4 hours, scaled to actual game intensity.

Why is this lower than my fitness watch? Watches tend to overestimate by 15–30% because they include any arm movement. The MET model is calibrated to actual oxygen consumption during basketball, which is more accurate for total body work.

Should I eat back all the calories? Almost always yes, on the same day or the next morning. Under-fueling during a tournament week is one of the most common mistakes in amateur basketball. The carb target here is a floor, not a ceiling.

Does this include practice? No — practice is typically lower intensity (5–6 METs) and longer duration. If you want a practice-day estimate, multiply game kcal by 0.75 and divide across practice hours.

Lean Mass Index (LMI). Lean Mass Index = Lean Body Mass (kg) / Height² (m). LMI is the only body-composition metric with established position norms in basketball literature. The rough position targets:

• Guards: LMI 19–22, BF% 7–12%
• Wings: LMI 21–24, BF% 8–13%
• Forwards: LMI 23–26, BF% 9–14%
• Bigs: LMI 24–28, BF% 10–16%

Why position norms differ. Bigs carry more mass because they need it for post leverage and rebounding. Guards run more total distance per game and benefit from a lower mass for energy efficiency. These are norms, not rules — exceptions exist in every era.

When body-fat estimates are unreliable. Most consumer scales using bioelectrical impedance have ±3–4% error. Calipers with a single site have even more. The 7-site Jackson-Pollock or DEXA scans are the practical gold standard for non-pro athletes. If you used a gym scale, round your input to whole percent and treat the result as directional, not precise.

The recommendation logic:

• LMI below range → prioritize hypertrophy / strength block
• LMI in range, BF% above range → small caloric deficit, hold protein high
• LMI in range, BF% in range → maintain
• LMI in range, BF% below range → small surplus, watch for overtraining

I'm 15 and growing. Should I bulk? No. Adolescent athletes should focus on strength and skill development; the body will fill out naturally with adequate protein and sleep. Forced bulking under-16 adds fat more than muscle and can impair mobility.

My BMI says I'm obese but I can dunk. What's going on? BMI doesn't separate muscle from fat, and athletic populations are systematically misclassified. A 90 kg, 12% body-fat, 190 cm player has a BMI of 24.9 (overweight) but an LMI of 21.0 (right in the guard range). This is normal.

Do these norms apply to women's basketball? Position norms shift by ~1–2 LMI lower for female players due to absolute lean mass differences, but the same logic applies. Use this calculator as a starting framework, not a target.

The composite score is the position-weighted sum of six sub-scores. Each sub-score is normalized on a 0–100 scale, where 50 represents the median for that position:

Sub-score normalization. For each metric, the 50th-percentile value for the position maps to a sub-score of 50. A value one standard deviation above maps to ~70, two above to ~90, etc. Below-median maps symmetrically. The composite is therefore position-relative: a 65 for a guard and a 65 for a big mean very different absolute values.

Why no single score is "elite". The composite is best read as a profile: a 78 with vertical 90 / agility 50 means "explosive but needs change-of-direction work". A 50 with vertical 50 / agility 90 means "shifty but won't dunk on many people". The position weighting tries to surface this, but you should still read each sub-score.

I don't know my sprint time. Should I still try? Yes — enter your best honest estimate from a recent session. Sprint times drift ~0.1–0.2s between fully rested and pre-practice; pick the rested value for the cleanest comparison.

How is lane agility defined here? The classic NBA Combine lane agility protocol: start at the baseline corner, sprint 4× forward to the free-throw line, then 4× back to the baseline, with direction changes at each cone. We use the 4×5+5×4 variant (touching each cone) which is the most common in college testing.

Why estimate approach jump instead of asking for it? Most recreational players have never tested their approach jump cleanly. A reasonable estimate from CMJ is: approach vertical ≈ CMJ × 1.13 + 6 cm for trained players, with the multiplier shrinking as CMJ grows. Enter your CMJ and let the estimator do its job.