Jump Encyclopedia Q&A

Common causes: 1. No periodization — doing the same work lets the body adapt and the stimulus stops being effective. Design a base → strength → power → peak cycle. 2. Strength base too low — plyometric gains are limited below a 1.5x bodyweight squat (Sánchez-Sixto et al., 2021). Build strength first. 3. Poor plyometric parameters — 2-3 sessions/week with 50-100 contacts is ideal; too much masks power with fatigue, too little under-stimulates. 4. Recovery gaps — sleep <7h measurably lowers force output (Reilly & Edwards, 2007); poor nutrition limits anabolism. 5. No objective assessment — what isn't measured isn't managed. Use this platform's diagnosis and target the weak areas.

References: Sánchez-Sixto et al. (2021) J Strength Cond Res; Reilly & Edwards (2007) Sports Med; NSCA Essentials (4th ed.) Ch.21

Along the neuromuscular adaptation timeline: • 2-4 weeks (neural): better motor-unit recruitment and intermuscular coordination; beginners sometimes see +2-5cm, while trained athletes may see little or nothing this early. • 4-8 weeks (strength): increased fiber CSA and max strength; squat and similar metrics clearly change. • 8-12 weeks (conversion): plyometric effects show up as strength converts to power; CMJ gains of 5-15cm are common in untrained or detrained athletes but much smaller in well-trained athletes. • 12+ weeks: compounding periodized gains, but the curve flattens. Key variables: lower starting level = faster gains; training quality beats duration; women, older athletes and advanced athletes should use more conservative expectations. No change in 12 weeks = the plan needs adjustment.

References: Verkhoshansky & Siff (2009) Supertraining Ch.5; NSCA Essentials (4th ed.) Ch.18

A plateau means the body has adapted to the current stimulus. Systematic breakout strategies: 1. F-V profile diagnosis — Jiménez-Reyes et al. (2017): force deficit (strong but not high) → add speed-type training; velocity deficit (high but weak) → add strength-type training. 2. Change training variables — sets, reps, load, rest, exercise order; any change breaks adaptation. 3. Deload — reduce volume 50-70% for a week. Sometimes you step back to leap forward. 4. Check the recovery trio — sleep, nutrition, stress. Chronic stress → cortisol ↑ → testosterone ↓ → progress blocked. 5. Contrast training — alternate high-intensity low-volume with low-intensity high-volume.

References: Jiménez-Reyes et al. (2017) Scand J Med Sci Sports; Samozino et al. (2012) Med Sci Sports Exerc

Detraining timeline: • 1-2 weeks off: mild neural decline (5-8% strength loss); jump height barely changes or drops 2-3cm. • 3-4 weeks: muscle CSA starts falling, strength loss 10-15%, CMJ down 5-8cm. • 8+ weeks: significant regression, but muscle memory (retained myonuclei) allows fast regain. Minimum maintenance: 1 strength + 1 plyometric session per week maintains 80-90% of condition. After a full break, 4-8 weeks of retraining returns you to baseline (muscle-memory effect).

References: Mujika & Padilla (2000) Sports Med; Bruusgaard et al. (2010) PNAS

The meta-analysis by Sánchez-Sixto et al. (2021) confirms combined strength + plyometrics beats either alone. Recommended phase ratios: • Base adaptation (weeks 1-4): strength 75% + plyo 25% (low-intensity entry). • Max strength (weeks 5-8): strength 65% + plyo 35%. • Power conversion (weeks 9-12): strength 40% + plyo 60%. • Peak/in-season (week 13+): strength 30% + plyo 70%. Same day: strength in the morning + plyo in the afternoon (6h apart), or on separate days. For most athletes, avoid maximal plyometrics immediately after heavy strength — fatigue destroys movement quality and raises injury risk. Advanced contrast/compound sessions can pair heavy lifts with low-volume jumps, but only when prescribed by a coach and with long rests.

References: Sánchez-Sixto et al. (2021) Sports Med; NSCA Essentials (4th ed.) Ch.18; Verkhoshansky & Siff (2009) Supertraining Ch.7

By experience level: • Beginner (<6 months): 2-3 sessions/week, 45-60 min, focused on movement patterns + base strength. • Intermediate (6-24 months): 3-4 sessions/week, 60-90 min, split upper/lower + plyometrics. • Advanced (>2 years): 4-5 sessions/week, 60-90 min, double sessions possible. Key gauge: RPE 7-8/10. Persistent soreness + insomnia + low mood + elevated resting heart rate = overtraining warning — cut volume immediately.

References: NSCA Essentials (4th ed.) Ch.21; Bompa & Buzzichelli (2019) Periodization (6th ed.)

Yes, but with a clear ceiling. • Absolute beginners (<3 months): bodyweight can add 10-15cm — neural adaptation plus basic strength. • Intermediate and above: bodyweight hits a bottleneck; you must add external load. Jumping needs force levels far beyond bodyweight stimuli. Best strategy: use bodyweight as a supplement (warm-up activation, single-leg variations, rehab), not a replacement for barbell/dumbbell work. Single-leg bodyweight variations (pistol squats, single-leg bridges) raise intensity but still cap out.

It's not either/or — it's periodization: • Full squat (parallel or below): develops full-ROM strength, CSA and max strength reserve. The staple of accumulation phases. • Quarter squat (130-150° knee): matches the takeoff angle (takeoff knee ≈130-140°) with higher specific transfer. Used in conversion phases. • Half squat (90-100°): a compromise balancing leverage and transfer. Recommendation: build the base with full squats (4-6 weeks), add quarter squats and loaded jumps in the conversion phase (4-6 weeks), and peak with quarter squats and plyometrics.

References: Verkhoshansky & Siff (2009) Supertraining Ch.3; Hartmann et al. (2012) Sports Med

Rest length directly changes training quality and adaptation: • Max strength (>85% 1RM): 3-5 min — fully restore ATP-CP. • Plyometric/power: 2-5 min — every jump must be maximal. • Hypertrophy accessory: 60-90s — metabolic stress drives growth. • Core/rehab: 30-60s — low-load high-control, short rest is fine. Common error: too little rest in plyometrics (<90s) turns later sets into 'fatigued jumping' instead of 'explosive jumping'. Fewer sets at full quality beats more sets at reduced quality.

References: NSCA Essentials (4th ed.) Ch.15; Verkhoshansky & Siff (2009) Supertraining Ch.4

Plyometrics use the stretch-shortening cycle (SSC) — eccentric → isometric → concentric — to maximize power output. Both fast SSC (contact <0.25s, e.g. depth jumps) and slow SSC (>0.25s, e.g. box jumps) should be trained. NSCA entry criteria: 1. Squat ≥1.5x bodyweight — enough strength to absorb impact. 2. No acute lower-limb injury history — especially Achilles, patellar, ACL. 3. At least 3 months of systematic strength training. 4. Can perform a quality depth drop from 30cm (stable, quiet landing). If you don't meet these: start with low-intensity plyometrics (pogo jumps, low box jumps, ladder drills) and build the strength base.

References: NSCA Essentials (4th ed.) Ch.18; Verkhoshansky & Siff (2009) Supertraining Ch.6

The depth jump is the gold-standard jump exercise — and the most commonly botched. Correct execution: 1. Box height: start 30-45cm. Test criterion — contact <0.25s and rebound >25cm. Too high → contact too long → SSC effect lost. 2. Step off — don't jump off! Jumping off pre-activates the muscles and weakens the SSC stimulus. 3. Contact: both feet together, stiff ankles (no soft feet), contact as short as possible (<200ms target). 4. Rebound direction: straight up! Not forward. Jump as if the floor is red-hot. 5. Landing posture = takeoff posture. Common errors: box too high → contact >0.3s → becomes 'jump down then jump up'; loud landings → poor eccentric control; forward takeoff → leaked force.

References: Verkhoshansky & Siff (2009) Supertraining Ch.6; Bobbert et al. (1987) Int J Sports Med

Foot contacts are the standard volume unit — one contact = one foot or both feet landing once. Weekly contact recommendations (NSCA): • Beginner: 60-100/week • Intermediate: 100-150/week • Advanced: 120-200/week. Example: box jumps 3×5 = 15 contacts; depth jumps 4×4 = 16; hurdle hops 3×8 = 24; total 55 — within one session's range. Monitoring: if next-week jump tests drop >5% or RPE stays high → cut contacts 20-30%. Quality always beats quantity — 100 full-power contacts beat 200 fatigued ones.

References: NSCA Plyometric Volume Guidelines; Verkhoshansky & Siff (2009) Supertraining Ch.6

Warming up before plyometrics is critical — cold muscles doing high-intensity SSC get injured. Standard protocol (15-20 min): 1. General warm-up (5 min): light aerobic (jump rope, dynamic movements) to raise body temperature. 2. Dynamic stretching (5 min): leg swings (front-back + lateral), hip circles, ankle alphabet. 3. Activation (5 min): glute bridges 2×15, banded lateral walks, A-skips 2×15m. 4. Specific prep (3-5 min): low-intensity pogo jumps 2×10, low box jumps 2×3, progressing toward training intensity. Key: after warming up you should feel 'light and springy', not tired. If the warm-up tires you → too much warm-up.

References: FIFA 11+ Warm-up Protocol; NSCA Essentials (4th ed.) Ch.14

Absolutely not. Reasons: 1. Nervous-system recovery — high-intensity SSC work needs 48-72h for CNS recovery. 2. Tendon recovery — collagen synthesis in the Achilles and patellar tendon takes 36-72h after intense SSC. 3. Consecutive-session risk — fatigue accumulates → landing mechanics degrade → injury risk rises exponentially. Minimum gap: at least 48h between high-intensity plyometric sessions. Typical week: Mon/Thu = high-intensity plyometrics; Tue/Fri = strength; Wed/Sat = low-intensity/recovery; Sun = full rest.

References: Verkhoshansky & Siff (2009) Supertraining Ch.4; NSCA Essentials (4th ed.) Ch.18

Patellar tendinopathy is the #1 injury in jump training — the tendon connects the patella to the tibia and takes 8-12x bodyweight during jumps. Prevention (evidence-based): 1. Progressive loading — increase weekly plyometric volume by ≤10%. 2. Posterior-chain strength — strong hamstrings and glutes share the patellar load (Harris et al., 2020). 3. Thorough warm-ups + quad stretching after sessions. 4. Avoid large jump volumes on concrete. 5. Isometric prehab — wall sits 3×45s, 2-3x/week. Treatment (four rehab phases): • Phase 1 (isometric): wall sits 5×45s, twice daily. • Phase 2 (eccentric): decline-board eccentric squats 3×15, slow 3-4s lowering, pain ≤3-4/10. • Phase 3 (reloading): progressively restore load. • Phase 4 (return): low-intensity plyometrics → gradual intensity. If severe (>3 months without improvement), see a professional.

References: Malliaras et al. (2015) Br J Sports Med; Harris et al. (2020) J Orthop Sports Phys Ther; Rudavsky & Cook (2014) Br J Sports Med

Medial tibial stress syndrome (MTSS) is an inflammatory response to overload of the tibial periosteum. Acute management: 1. Cut training volume 50%, substitute low-impact aerobic (swimming, cycling, elliptical). 2. Ice 10-15 min, 2-3x/day. 3. Strengthen the anterior shin — heel walking 3×30m, banded toe pulls 3×20. 4. Check your shoes — running shoes last ~500-800km. Prevention after recovery: 1. Progress volume gradually — weekly total jumps +≤10%. 2. Surface choice — grass/rubber track >> concrete. 3. Arch strengthening — short-foot exercise, towel curls. ⚠️ If pain persists after 2 weeks of rest → see a doctor to rule out a tibial stress fracture.

References: Moen et al. (2009) Sports Med; Warden et al. (2014) Br J Sports Med; Beck (1998) Am J Sports Med

Lateral ankle sprains by grade: • Grade I (mild stretch): 1-2 weeks to light training. • Grade II (partial tear): 4-6 weeks of gradual return. • Grade III (complete tear): 3-6 months, needs medical assessment. Functional return criteria (not time-based!): 1. Single-leg stand >30s (eyes open, flat floor) → progress to eyes closed 30s. 2. Single-leg calf raises >15 pain-free. 3. 10 single-leg small hops — stable, no fear. 4. Y-Balance test — left/right difference <4cm. Return stages: pain-free ROM → band resistance → proprioception → bodyweight jumps → plyometrics. Progress only when each stage is pain-free. Returning too early raises re-sprain risk 5x.

References: Petersen et al. (2013) Br J Sports Med; Verhagen et al. (2004) Am J Sports Med; NCAA Injury Surveillance System

Pain classification in sports medicine: ✅ Good pain (DOMS): bilateral and symmetric, muscle soreness, 'pleasant ache' on pressure, fades over time, doesn't change movement quality, disappears in 24-72h. ✗ Bad pain (injury signal): unilateral sharp/stabbing or burning, pain inside a joint, worsens with pressure, with swelling/heat, or makes you change the movement (limping, protective compensation). Iron rule: any pain that changes your movement pattern = stop. Training through compensation patterns causes chain injuries elsewhere.

The Achilles is the strongest tendon in the body, but jump training loads it heavily. Tendinopathy prevention: 1. Progressive load — weekly volume +≤10%. 2. Isometrics — calf-raise peak holds 3×45s, 3-4x/week (O'Neill et al., 2019). 3. Ankle mobility — limited dorsiflexion (<10cm knee-to-wall) is a risk factor. 4. Avoid weekend-warrior spikes. 5. Eccentrics — straight- and bent-knee slow lowers (3-4s). Rupture warning signs: persistent morning stiffness (>30 min), mid-tendon thickening + pain, abnormal ultrasound structure, or a sudden 'kicked in the heel' feeling with a visible gap — that's an emergency, get surgery.

References: O'Neill et al. (2019) Am J Sports Med; Alfredson et al. (1998) Am J Sports Med; Maffulli et al. (2004) J Bone Joint Surg

Factor weighting: 1. Training level (60-80%) — the largest controllable variable. 2. Relative strength (strength ÷ bodyweight) — predicts jump better than absolute strength. Every 1kg of fat lost (strength unchanged) adds ~1-2cm of CMJ. 3. Body composition — each 1% lower body fat adds roughly 1-3cm of CMJ. 4. Limb ratios — relatively longer legs theoretically allow a longer force application, but also add rotational inertia. 5. Absolute height — Nate Robinson (1.7m, ~110cm CMJ) proves height isn't decisive. Core message: training is the biggest lever. Don't obsess over genetics — optimize training and recovery.

References: NSCA Essentials (4th ed.) Ch.2; Verkhoshansky & Siff (2009) Supertraining Ch.3

Training priorities by age: • Youth (13-18): the best window for neural plasticity — prioritize movement patterns, coordination and technique. Strength training is safe — avoid maximal loads (<85% 1RM). Plyometrics start low-intensity. • Prime (18-30): high testosterone and recovery capacity — handle high-intensity strength and plyometrics. • Mature (30-40): recovery slows — schedule more recovery days; strength training matters more. • Senior (40+): focus on maintenance over breakthrough — strength preserves muscle and bone density; plyometrics stay low-intensity. It's never too late to start.

References: Faigenbaum et al. (2009) J Strength Cond Res; NSCA Long-Term Athletic Development Position Statement

Flat feet (Pes Planus) mechanism: a normal arch acts like a spring during jumping — collapsing on landing stores energy, rebounding releases it on push-off. A flattened arch weakens that spring effect — theoretically reducing energy return by ~5-10%. But it's not decisive — many elite athletes have flat feet. Improvement strategies: 1. Foot intrinsic training — short-foot exercise, towel curls, barefoot walking on sand. 2. Shoe choice — flat, firm soles (Nike Metcon, Reebok Nano); avoid soft running shoes. 3. Orthotics — if function is clearly limited. 4. Calf flexibility — flat feet often accompany tight soleus.

References: McKeon et al. (2015) Br J Sports Med; Headlee et al. (2009) J Orthop Sports Phys Ther

It depends on body composition and relative strength: • Key concept: relative strength = squat 1RM ÷ bodyweight. >1.8 → excellent jump potential; <1.2 → prioritize strength or fat loss. • Fat-loss strategy: each 1kg of pure fat lost (strength maintained) adds ~1-2cm CMJ. But if you lose strength while cutting, jumping drops. • Optimal weight: the lower the better, provided your squat is >1.8x bodyweight. If your squat is only 1.2x, build strength before cutting. • The BMI trap: BMI doesn't distinguish muscle from fat. Many jump athletes have BMI >25 with body fat <12%. Core principle: prioritize relative strength.

References: NSCA Essentials (4th ed.) Ch.9; Markovic & Jaric (2007) J Strength Cond Res

Nutrition strategy for jump training (70kg athlete): • Protein: 1.6-2.2g/kg/day (~112-154g) — spread across 4-5 meals, 30-40g each. • Carbs: 4-6g/kg/day on training days (~280-420g) — high-intensity power training runs on glycolysis. • Fat: 0.8-1.2g/kg/day — prefer monounsaturated fat and omega-3 (fatty fish). • Post-training window: 20-40g protein + 40-80g carbs within 30-60 min. • Water: 3-4L/day — 1% dehydration lowers power output 2-3%. • Strictly avoid: alcohol (suppresses protein synthesis up to 30% for 24-48h) and highly processed foods.

References: Thomas et al. (2016) J Acad Nutr Diet; Maughan & Shirreffs (2010) Scand J Med Sci Sports; Jäger et al. (2017) J Int Soc Sports Nutr

Supplements have a strict priority order in jump training: Priority 1 (food): whole foods beat any supplement. Consider supplements only when you can't get enough protein from food (e.g. need 150g/day but diet provides 100g). Evidence-supported: • Whey protein: convenient quality protein; 30g post-training delivers amino acids fast. • Creatine monohydrate (5g/day): clear evidence for power/sprint/jump (Kreider et al., 2017). • Caffeine (3-6mg/kg, 60 min pre-training): acutely raises power output 2-5%. • Beta-alanine (3-5g/day): buffers intramuscular acidosis; benefits 60-240s high-intensity efforts. Little/no evidence: BCAAs (whole protein is better), glutamine, L-carnitine. Core message: fix your diet first, then consider supplements.

References: Kreider et al. (2017) J Int Soc Sports Nutr; Thomas et al. (2016) J Acad Nutr Diet

Sleep is the most underrated lever in jump training. Evidence: 1. Sleep <6h → strength down 10-15% (Reilly & Edwards, 2007). 2. Sleep deprivation lowers testosterone (Leproult & Van Cauter, 2011), blocking muscle repair and growth. 3. REM sleep is a key window for motor-skill consolidation. 4. A Stanford basketball study showed >8h sleep improved sprint speed and shooting accuracy. Optimization: 1. Fixed bed and wake times (within 30 min). 2. No screens for 1h before bed (blue light suppresses melatonin). 3. Completely dark bedroom at 18-20°C. 4. Warm shower before bed (40°C × 15 min) → core cooling induces sleep. 5. Avoid heated discussions and caffeine (5-6h half-life). 6. Duration varies — most athletes need 7-9h.

References: Leproult & Van Cauter (2011) JAMA; Mah et al. (2011) Sleep; Reilly & Edwards (2007) Sports Med

Delayed-onset muscle soreness (DOMS) is a normal response to eccentric work, peaking at 24-72h. Evidence-supported recovery: 1. Light active recovery — 15-20 min low-intensity cycling/walking to improve blood flow. 2. Adequate sleep — growth hormone pulses during slow-wave sleep; it's the natural repair window. 3. Protein intake — 20-40g every 3-4h continuously feeds repairing muscle. 4. Foam rolling/massage — moderate (not brutal) reduces the perceived soreness. Limited or ineffective: ice baths (may blunt hypertrophy adaptations), NSAIDs (suppress protein synthesis!), stretching (doesn't reduce DOMS). Core: DOMS ≠ injury. Normal fading in 48-72h is fine. Sharp pain / one-sided pain / joint pain is not DOMS.

References: Cheung et al. (2003) Sports Med; Jäger et al. (2017) J Int Soc Sports Nutr; Barnett (2006) Sports Med

The CMJ vs SJ comparison is the simplest, most important jump-bottleneck diagnostic: • SJ (from a static half-squat): measures pure concentric ability. • CMJ (dip then jump): measures concentric + SSC elastic use. • The difference (CMJ−SJ) = SSC utilization / elastic contribution. Normal difference is ~10-20% of CMJ. Interpretation: ➤ Large difference (>20% CMJ) → good elasticity, relatively weak strength → prioritize max strength. ➤ Small difference (<10% CMJ) → strength reserve exists but isn't being used → plyometrics/SSC work to improve elastic use. Complete this platform's assessment — the report identifies the weak direction precisely.

References: Van Hooren & Zolotarjova (2017) Sports Med; Bobbert et al. (1996) Med Sci Sports Exerc

Created by Samozino and Jiménez-Reyes, the F-V profile fits the muscle's force-velocity relationship from CMJ/SJ heights at different loads: • F₀ (theoretical max force at zero velocity): max dynamic force. • V₀ (theoretical max velocity at zero load): max shortening velocity. • Sfv (F-V slope = F₀/V₀): force-velocity balance. • Pmax (max power = F₀×V₀/4): peak power. Diagnosis: 1. F-V imbalance (Sfv deviates >40% from optimal) → targeted training can improve 15-30% (Jiménez-Reyes et al., 2017). 2. Force deficit → prioritize strength. 3. Velocity deficit → prioritize speed. Test frequency: once per training cycle (8-12 weeks), not weekly — variables change slowly. If you don't have a strength base (squat <1.5x bodyweight), don't test F-V yet — build strength first. Note: BounceLab's in-app diagnosis uses a simplified strength-adjusted jump index (CMJ vs expected value from relative squat), not a true multi-load F-V profile.

References: Jiménez-Reyes et al. (2017) Scand J Med Sci Sports; Samozino et al. (2012) Med Sci Sports Exerc; Morin & Samozino (2016) Sports Med

Effective tracking = objective data + consistent conditions + sensible frequency: 1. Pick one standard test — CMJ (free arm swing) is the most common; it's more stable than SJ/DJ and sensitive to training changes. 2. Fix conditions — same day and time (afternoon/evening is peak), same court/shoes, same warm-up. 3. Frequency — once per week (same day, e.g. Saturday afternoon). Daily fluctuation of 2-3cm is normal — watch the trend, not single days. 4. Log variables — sleep, RPE, previous-day volume. Use a log, not memory. 5. Smallest worthwhile change (SWC) — roughly 2-5% of CMJ for trained athletes (1-2cm). Only changes beyond SWC are real, not daily noise. 6. Supporting metrics — squat 1RM (monthly), 10m/30m sprint, Reactive Strength Index (RJI = jump height / contact time in depth jumps).

References: Hopkins (2000) Sports Med; Claudino et al. (2017) Sports Med; Bosco et al. (1983) Eur J Appl Physiol

ROI ranking for jump improvement (meta-analytic and practical evidence): 1. Foundational strength training (highest ROI, especially if relative squat <1.5x) — squats and deadlifts build the strength reserve. Sánchez-Sixto et al. (2021): strength + plyo > plyo alone. 2. Strength→power conversion — loaded jump squats (30% 1RM), power cleans/hang cleans. Trained strength must be expressed at speed. 3. Depth jumps — once the strength base is met (>1.5x BW squat), they accelerate gains. Verkhoshansky's classic study: 8 weeks of depth jumps added 15-20cm CMJ. 4. Sport-specific technique — approach-takeoff optimization transfers 5-15%. 5. Supplements/nutrition — on top of optimized training, creatine + caffeine add ~2-5% acutely. Core logic: build the strength base → convert strength to power → deepen elastic use with plyometrics → refine technique for the final few percent.

References: Sánchez-Sixto et al. (2021) Sports Med; Verkhoshansky & Siff (2009) Supertraining Ch.6; Markovic (2007) Br J Sports Med

Stand behind a line with feet shoulder-width, dip and swing the arms back, then jump forward with a full hip-knee-ankle extension and land on both feet. Measure from the front edge of the start line to the point of contact closest to the line (usually the back of the heels), take the best of three attempts with 60-90 seconds of rest, and keep the shoes, surface and warm-up identical every test. As a rough athlete reference: trained males often jump 2.3-2.6 m and trained females 1.8-2.1 m, but your own 8-12 week trend matters more than a single number.

References: NSCA Essentials (4th ed.) Ch.13; Castro-Piñero et al. (2009) J Strength Cond Res

A strength deficit means your jump expression is already efficient but your force reserve is low; a velocity deficit means you are strong but cannot express that force quickly in the short ground-contact time of a jump. Quick checks: 1. BounceLab strength-adjusted jump index — if CMJ is clearly above the value expected from your relative squat, strength is the ceiling; if clearly below, conversion/RFD is the bottleneck. 2. CMJ vs SJ gap — a large gap means elastic/reactive use is good; a small gap points to speed/conversion work. 3. Relative squat — below ~1.3-1.5x bodyweight usually means strength should come first. 4. Loaded jump speed and sprint/jump mismatch provide supporting evidence. Strength deficit → prioritize heavy squat, deadlift and unilateral strength with low plyometric volume. Velocity deficit → keep strength on maintenance and shift toward jump squats, short-contact plyometrics and sprints. Re-test under identical conditions every 4-6 weeks before changing direction.

References: Jiménez-Reyes et al. (2017) Scand J Med Sci Sports; Samozino et al. (2012) Med Sci Sports Exerc; Morin & Samozino (2016) Sports Med

This is a badly over-generalized myth. Scientific facts: 1. How far the knees pass the toes depends on individual femur/tibia length ratios. Long femurs + short shins mean the knees must pass the toes in a full squat — a normal anatomical variation. 2. Banning forward knee travel forces excessive torso lean → more lumbar shear — more dangerous! 3. During a jump takeoff the knees pass the toes anyway — avoiding it in training is non-specific. What to actually watch: overall biomechanics — neutral spine, heels down, knees not caving. Individual stance width and depth are the real variables.

References: Fry et al. (2003) J Strength Cond Res; Schoenfeld (2010) J Strength Cond Res; Hartmann et al. (2012) Sports Med

This is one of the most harmful myths about youth training. Facts: 1. No scientific evidence shows strength or plyometric training stunts height. 2. Appropriate resistance training actually increases bone density and skeletal health. 3. Growth-plate injuries only happen with severe acute trauma (like high-velocity impacts); normal training loads don't cause them. 4. The international consensus (NSCA, ACSM, IOC) is that youth strength training under proper guidance is safe and beneficial. What really affects height: genetics (70-80%), malnutrition, chronic disease, severe sleep deprivation, hormonal imbalance. Training is not among them.

References: Faigenbaum et al. (2009) J Strength Cond Res; Lloyd et al. (2014) Br J Sports Med; ACSM Youth Strength Training

Hypertrophy is tightly linked to training parameters: 1. Typical jump-training parameters (low reps, high power, long rest) favor neural adaptation and power — hypertrophy effects are small. 2. What actually adds size: moderate reps (8-12RM), short rests (60-90s), high volume — that's a bodybuilding recipe, not jump-specific training. 3. In practice, elite jumpers usually have defined, athletic legs — functional muscle, not show muscle. If you're female and worried about bulk: female testosterone is ~5-10% of male levels, so natural hypertrophy potential is limited — jump training will make you firmer and more defined, not bulky.

References: Schoenfeld et al. (2016) J Strength Cond Res; NSCA Essentials (4th ed.) Ch.15

One of the most harmful misconceptions about athletic ability. Facts: 1. Genetics explain roughly 40-60% of CMJ variance, meaning 40-60% is determined by environment and training. 2. Even genetically fixed fast-twitch ratios can be optimized by training. 3. Extreme examples: an untrained person jumps ~30-40cm; 1-2 years of systematic training reaches 50-70cm — nearly double. 4. What's truly locked in — fiber I/II ratio, limb proportions, tendon attachment points — explains only a small share of variance. Conclusion: if you haven't trained systematically for 2+ years, don't say 'I was born unable to jump'. Train first, then talk about ceilings.

References: Bouchard et al. (2011) J Appl Physiol; Yang et al. (2003) Am J Hum Genet; Verkhoshansky & Siff (2009) Supertraining Ch.2

The arm swing contributes 10-15% of jump height (Harman et al., 1990; Lees et al., 2004) — on a 60cm CMJ, that's 6-9cm. Three mechanisms: 1. Momentum transfer — swinging the arms up transfers downward momentum to the body, increasing ground reaction force. 2. Shoulder torque — the reaction torque of accelerating arms helps hip-knee extension. 3. Timing — the swing lengthens force application by ~15-20ms, increasing impulse (F×Δt). Correct technique: start with arms swung fully back → continue back through the dip → on the drive, whip them forward-up at maximum speed (fingertips toward the sky). Common errors: swinging too early/late, swinging forward instead of up. Drills: overhead med-ball throws, weighted pull-ups, video analysis.

References: Harman et al. (1990) Med Sci Sports Exerc; Lees et al. (2004) J Strength Cond Res; Feltner et al. (1999) J Biomech

Deeper isn't better — there's an optimal range. Key research: 1. Self-selected depth is usually near-optimal (~90-100° knee). 2. Too shallow (<45°): shorter force application → less impulse. 3. Too deep (>120°): SSC elastic storage efficiency drops — some energy dissipates as heat. 4. A fast countermovement maximizes elastic storage and reuse (Bobbert et al., 1996). Practical advice: let the dip be natural and fluid — don't deliberately control depth or speed; the dip-to-takeoff transition must be quick (a pause makes it an SJ, not a CMJ); use video to check for unnatural pauses or excessive sinking.

References: Bobbert et al. (1996) Med Sci Sports Exerc; Van Hooren & Zolotarjova (2017) Sports Med

The approach jump is the most common takeoff in basketball/volleyball: 1. Penultimate step — slightly lower the center of mass to prepare for braking + drive. Heel → full foot → forefoot. Lower the center ~5-10cm — too much loses horizontal speed. 2. Block step (final step) — toe-first, transitioning quickly to the full foot like a brake, converting horizontal momentum into vertical. The foot lands 20-30cm in front of the center of mass. 3. Takeoff — both arms whip up, the free knee drives up fast to add vertical momentum, takeoff angle ~60-75° (not 90°). Common errors: block step too far → 'over-brakes' → horizontal speed hits zero; block step too close → horizontal speed isn't converted → you jump forward instead of up.

References: Dapena & Chung (1988) J Biomech; Stefanyshyn & Nigg (1998) J Biomech

Biomechanical differences: • Double-leg (CMJ-type): symmetric force, full SSC use, larger force output, longer contact (300-500ms) — for standing jumps under the rim. • Single-leg (RJ-type): asymmetric force, uses horizontal→vertical conversion, shorter contact (150-250ms), more Achilles and arch contribution — for takeoffs after running. Training advice: most athletes should train both — double-leg strength base (squats, CMJ) + single-leg specificity (Bulgarian split squats, single-leg bounds). Two-leg height ≠ one-leg height — they correlate but don't equal. Use test data — compare CMJ with approach reach; a large gap shows which direction is the weak link.

References: Verkhoshansky & Siff (2009) Supertraining Ch.6; Bobbert et al. (1987) Int J Sports Med

A full macrocycle is typically 12-16 weeks in four mesocycles: • Weeks 1-4 (base adaptation / GPP): build training tolerance and correct movement patterns. Goblet squats, bodyweight single-leg work, low-intensity plyometrics, core. RPE 6-7. • Weeks 5-8 (max strength / SPP1): raise lower-body 1RMs. Full squats, deadlifts, Bulgarian split squats, weighted hip thrusts. Plyometrics stay low-volume. RPE 8-9, low reps. • Weeks 9-12 (power conversion / SPP2): strength→power. Quarter squats, loaded jumps, depth jumps, hurdle hops, high box jumps, sprints. Strength maintenance only. RPE 7-8. • Weeks 13-14 (peak/testing): maximize jump performance. High-intensity low-volume plyometrics, technique work, lots of rest. Volume drops to 50-60%. • Weeks 15-16: deload / active recovery → new cycle.

References: Bompa & Buzzichelli (2019) Periodization (6th ed.); Verkhoshansky & Siff (2009) Supertraining Ch.7; NSCA Essentials (4th ed.) Ch.21

Deloading is an essential part of periodized training. Purpose: 1. Neuro-muscular recovery. 2. Tendon/ligament adaptation (adapts much slower than muscle; needs 6-10 weeks). 3. Overtraining prevention. 4. Supercompensation — performance after a deload often surpasses the previous peak. Three methods: 1. Half volume + same intensity (most recommended) — e.g. 3×5@85% → 2×5@85%. 2. Lower intensity + same volume — 60-70% 1RM for normal sets. 3. Full rest — light aerobic and stretching only. Frequency: one deload week every 4-6 weeks. Signals you need one: RPE keeps climbing, sleep worsens, joints ache. Many jump PRs happen not in the hardest training week, but on the test week after a deload.

References: Verkhoshansky & Siff (2009) Supertraining Ch.4; Mujika & Padilla (2003) Med Sci Sports Exerc; Bompa & Buzzichelli (2019) Periodization (6th ed.)

In-season maintenance is about the 'minimum effective dose': • Strength: 1-2 sessions/week, compound movements. Keep intensity (>80% 1RM), cut volume (2-3 sets × 3-5 reps) — maintain, don't chase PRs. • Plyometrics: 1 session/week, low volume (30-50 contacts), moderate-high intensity, on a non-game day and >48h before competition. • Monitoring: test CMJ weekly. A drop >5% → reduce volume and add recovery. • Never: attempt squat PRs or high-intensity plyometrics in-season — injury risk is too high. In-season = maintain; off-season = build. Keep those goals separate.

References: Bompa & Buzzichelli (2019) Periodization Ch.12; NSCA Essentials (4th ed.) Ch.21

Progressive overload is the engine of progress: • Strength: add weight first. When you complete the target sets/reps with 1-2 reps in reserve → add 2.5-5% next week (lower body). Double progression — first add reps (3×5 → 3×6 → 3×7), then jump back to low reps with more weight. If technique degrades, don't add weight — refine form. • Plyometrics: add height/distance first. Improve the quality of each jump, then add sets. Increase contacts ≤10% per week. If jump height drops >5% or landings get loud → don't add volume, prioritize recovery. • General rule: never change volume and intensity at the same time — one variable at a time. If you fail the target twice in a row → deload. A training log is the best guide — decide with data, not feelings.

References: NSCA Essentials (4th ed.) Ch.15; Bompa & Buzzichelli (2019) Periodization Ch.5

Test anxiety over-activates the sympathetic nervous system (heart rate up, muscles tense, coordination down). Solutions: 1. Simulate test environments — schedule regular 'test days' in training so the body and brain get used to pressure. 2. Pre-performance routine — design a fixed pre-test sequence (3 deep breaths → 2 arm swings → 2 light jumps → test). A fixed routine lowers uncertainty → lowers anxiety. 3. Breath control — 4-7-8 breathing (inhale 4s → hold 7s → exhale 8s) quickly activates the parasympathetic system. 4. Cognitive reframing — reinterpret 'I'm nervous' as 'I'm ready'. The physiology of nervousness and excitement is nearly identical; the difference is interpretation. 5. Process goals over outcome goals — focus on technique cues, not height. 6. Stack success experiences — regular testing records build an evidence base for confidence.

References: Weinberg & Gould (2019) Foundations of Sport and Exercise Psychology (7th ed.); Yerkes-Dodson Law

Kinesiophobia is most common after injury recovery. Solutions: 1. Graded exposure: two-foot pogo jumps → low box jumps (20cm) → mid box (40cm) → depth drop (30cm) → depth jump (30cm) → high box jumps → depth jumps (45cm+). Advance only when each step feels fearless. 2. Cognitive-behavioral: identify automatic negative thoughts ('I'll get hurt') and challenge them with facts ('I've safely done this 100 times'). Externalize attention — focus on 'jump onto that box' rather than 'will my knee hurt'. 3. Reduce uncertainty — flat surfaces, crash pads, full warm-ups, a training partner present. 4. Build success experiences — record each completed level; after ~10 successes, fear naturally fades. 5. If needed, see a sport psychologist.

References: Ardern et al. (2013) Br J Sports Med; Vlaeyen & Linton (2000) Pain

Motivation fluctuates — even elite athletes have 'don't want to train' days. 1. Identity over outcome — 'I am a trainer' is more sustainable than 'I want to jump higher than X'. The first is identity; the second is a goal that can fail. 2. Process tracking over outcome tracking — log completion ('completed 85% of the plan this month'), not just jump data. Process is controllable; results fluctuate. 3. Social support — a training partner or online community. Accountability plus social pressure are powerful drivers. 4. Minimum commitment — 'I'll just do 10 minutes' — once started, you usually finish. Starting is the hardest part. 5. Rotate variables — change part of the training every 4-6 weeks to prevent boredom. 6. Reward milestones. 7. Accept fluctuation — not every cycle is a PR cycle; sometimes maintaining is winning.

References: Deci & Ryan (2000) Psychol Inq; Weinberg & Gould (2019) Foundations of Sport and Exercise Psychology

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