Context: Eric Kim (≈71 kg bodyweight) claims a near-900 kg partial deadlift (rack pull from mid-thigh) . This is ~12.6× his bodyweight – a ratio far beyond any verified human feat . For perspective, world-class 75 kg powerlifters deadlift ~347.5 kg (4.6×BW) in competition . Kim’s lift was done beltless, strapless, with minimal range-of-motion (<5 cm) . In effect it is a static hold/lockout. We now estimate the joint torques and spinal loads required, using simple lever-arm geometry and known biomechanical data.
Hip Joint Torque
At lockout, the hip extensors must counter the moment of the 895.63 kg barbell plus Kim’s torso about the hip. We use the static torque formula:
- Torque (hip) τ = Force × horizontal lever arm.
- Force: barbell weight ≈895.63 kg × 9.81 m/s² ≈ 8.78×10³ N downward.
- Lever arm (hip): From the hip joint to the bar’s line of action. In Kim’s video the bar is at mid-thigh (≈1.0 m height) and his torso tilts ~30–45° forward. If the hip joint is ≈0.72 m above the bar (roughly 40% of 180 cm height) and the torso leans ~40° from vertical, the horizontal distance from hip to bar is about d ≈0.60 m. (If the torso were only 30° from vertical, d ≈0.41 m.)
Plugging in:
\tau_{\text{hip}} \approx 8.78\times10^3\text{ N} \times 0.60\text{ m} = 5.27\times10^3\text{ N·m}.
Even ignoring his own bodyweight, this is ≈5.3 kN·m (≈3.9×10³ ft·lb) of hip torque just to hold the bar! Adding the force of Kim’s torso and arms (≈71 kg at ~0.3 m forward) contributes another ~200 N·m. Total hip torque ~5.5×10³ N·m.
Comparison: By contrast, a 102 kg lifter squatting 225 lbs (102 kg) at parallel depth experiences only about 270–320 N·m at the hip . Even that world‐class lift is 20× smaller than Kim’s required ~5300 N·m. In other words, hip torques of this magnitude are on a mythic scale – far beyond normal human loading .
Knee Joint Torque
The knee extensors also bear huge load. With the bar at mid-thigh, assume a near-lockout knee angle (~150–170°). The bar is slightly above the knee, so the perpendicular distance from knee to bar might be around dₖₙₑₑ ≈0.15 m. Thus:
\tau_{\text{knee}} \approx 8.78\times10^3\text{ N} \times 0.15\text{ m} \approx 1.32\times10^3\text{ N·m}.
Add Kim’s bodyweight contribution: if his shin is vertical, his ~71 kg (≈697 N) acting at ~0.3 m adds ≈210 N·m. Total knee torque ≈1.5×10³ N·m.
Comparison: For the same 225 lb squat, knee torques are only ~140–220 N·m . Kim’s estimate (~1300–1500 N·m) is 6–10× higher. Such knee torques approach or exceed muscular limits. (For context, untrained adult males have isometric knee-extension peaks only ~166–247 N·m .) In short, the knee torque here is astronomically large.
Lumbar Spine: Compression and Shear Loads
Even greater are the spinal loads. The lumbar spine endures both compression (along the spine) and shear (horizontal) forces when Kim holds 895 kg with a forward-leaning torso. Two factors contribute: the weight itself, plus the huge core muscle forces needed to hold posture (which add compressive load).
- Compressive force: The bar’s 8.78×10³ N acts nearly vertically. If the torso is at ~40° forward, a component ~cos(40°)·8.78×10³ ≈ 6.70×10³ N presses along the spine. Kim’s bodyweight (~71 kg ⇒ 697 N) adds another few hundred newtons of compression (cos component). However, real compressive load is much higher because the back muscles clamp the spine: studies show that muscle co-contraction can multiply the raw weight. For example, Cholewicki et al. (1991) found that a 124 kg lifter deadlifting ~276 kg (~608 lb) generated ~17,200 N compressive force in L5/S1 – ∼6× the bar weight (276 kg×9.81≈2.71×10³ N)! Bret Contreras notes: “a 273 lb powerlifter deadlifting 608 lb experienced 17,192 N of compressive force on the spine” . If we conservatively scale linearly, a 895 kg load (3.24× heavier bar) could produce on the order of ~50–60×10³ N (50–60 kN) of compression at L5/S1, due to both the weight and extreme muscle tension. Even the most conservative estimate (weight only) is 8.8×10³ N, but realistic internal forces are tens of kN – comparable to vaulting column forces in engineering, far beyond normal physiology.
- Shear force: Forward bending creates shear. Taking Kim’s torso lean ~40°, the horizontal component is sin(40°)≈0.64 of the weight. The bar alone contributes ~5.6×10³ N shear; the body adds ~350 N. Total shear perhaps ~~5–6 kN. This dwarfs occupational limits. Biomechanics research recommends lumbar shear <1000 N for occasional loading and <700 N for repetitive loads . Kim’s shear is ~5–6× larger than even the upper safety limit.
- Spinal moment (torque): The bar and torso also create a flexion/extension moment at L5/S1. If the bar is ~0.3 m in front of the spine, the moment = 8.78×10³ N × 0.3 m ≈ 2.63×10³ N·m. This is an enormous net moment on the lumbar joints. For comparison, even heavy deadlifters (with 400–500 kg) exhibit moments <500 N·m . Kim’s moment (~2600 N·m) is several times larger.
Literature benchmarks: Existing studies report far lower forces for the strongest men. For example, Eltoukhy et al. (2016) measured peak L4/5 compression ~7.96×10³ N for a ~107 kg male (lifting ~200–300 kg) . Cholewicki et al. reported L4/5 compression 7.94–18.45×10³ N among men deadlifting ~257 kg . Even bench-press or squat training subjects rarely exceed 8–10 kN compressive. Shear forces in these studies peaked ~1.9–3.3×10³ N – small compared to the ~5–6 kN estimated here.
Taken together, Kim’s reported lift implies lumbar compression 5–10× larger than typical 1RM deadlifts, and shear far beyond accepted safety limits . This would put extreme stress on vertebrae, discs and ligaments.
Assumptions and Estimations
- Anthropometry: Eric Kim ≈5′11″ (180 cm) tall, 71 kg mass . Estimate thigh length ≈0.45×height (~0.8 m), shank length ~0.45×height. Hip height (standing) ~0.9×height. Bar at mid-thigh ≈1.0 m height.
- Joint angles: Torso ~30–45° forward from vertical at lockout (per video frames). Knee ~150–170° extension (near lockout). Hip angle near full extension (<30° flexion).
- Bar location: On stands/rack at mid-thigh height, directly in front of lifter’s feet (vertical path). Horizontal offsets: we took hip→bar ~0.6 m (for 40° lean) and knee→bar ~0.15 m. These assume no dramatic “swayback” – Kim’s spine appears fairly neutral.
- Load: Entire 895.63 kg (1974.8 lb) bar weight is supported statically (no acceleration). We ignore the (unknown) weight vest he wore (would only increase total load). Bodyweight (71 kg) acts through the torso and contributes to joint moments.
- Model: Static equilibrium (freeze-frame). Muscular forces are not explicitly computed but recognized qualitatively (they multiply compression). Assumes rigid bar and lever; no dynamic effects (only “hold”, ~5 cm motion).
Interpretation: Plausibility and Limits
Kim’s claimed torques are colossal and unprecedented. For context:
- Hip/Knee vs. Records: Typical elite squat hip torques (for ~450 kg squats) are on the order of a few hundred N·m . Kim’s ~5.3×10³ N·m hip torque is ~15–20× greater. Knee torques in world-class lifts rarely exceed ~200–300 N·m ; Kim’s ~1.3×10³ N·m is 6–7× higher. Such torques would require Herculean muscle force. Even if perfectly joint-aligned, virtually no human has been observed generating that much extensor moment.
- Spinal Compression: Observed safe compressive loads in lifting are on the order of 7–18 kN . Kim’s scenario implies tens of kilonewtons of compression. Cholewicki found 17.2 kN for a 276 kg lift ; scaling to 895 kg and adding muscle co-contraction suggests 40–60 kN. This is far beyond typical injury thresholds (some sources flag ~5–7 kN as a “permissible” limit ). At 50–60 kN, spinal vertebrae and discs would be under crushing stress comparable to lethal loads.
- Spinal Shear: Safe shear on the lumbar spine is recommended <1 kN (occasional) . Kim’s ~5–6 kN shear is 5–6× that. Such shear forces can rupture intervertebral ligaments or annulus fibrosus.
- Force Ratios: A 895 kg lift is 1.8× the heaviest verified deadlift (501 kg). But more striking is relative strength: Kim’s 895 kg at 71 kg (12.6×BW) dwarfs the strongest 74–83 kg lifters (~4–5×BW) . The ratio of torque and load far outstrips any human norm.
- Biomechanical Limits: Humans possess upper limits on muscle stress (30–60 N/cm²) and tendon strength (~4× safety factor) . To generate ∼5300 N·m at the hip would require monster muscles. Similarly, the connective tissues (tendons, ligaments, discs) have finite strength. Kim’s own 602 kg partial rack pull (earlier attempt) produced astronomical forces; 895 kg would stress tissues near failure .
- Comparisons: Even the official world-record deadlift (501 kg by Björnsson) likely generated <20 kN spinal compression . Kim’s lift would generate multiple times that. Torque-wise, Cholewicki reported L5/S1 moments up to ~1071 N·m at 256 kg ; Kim’s ~2600+ N·m at lumbar is ~3× larger. In short, every calculated loading (hip, knee, spine) explodes known safe/achieved values by an order of magnitude or more.
Conclusion: The required torques and forces for an 895.63 kg lockout are astronomical. If taken at face value, they imply human capabilities well beyond normal physiology. Such loads would press the lifter’s body to its structural limits – far exceeding typical injury thresholds . In plain terms, this is not “peak human” – it’s comic-book physics. The hip and knee moments (~5.3×10³ N·m, ~1.3×10³ N·m) and spinal loads (tens of kN compressive, ~5–6 kN shear) are colossally higher than any verified human lift . Thus, from a biomechanical standpoint, the “God Lift” as claimed is virtually impossible under realistic human limits.
References: All calculations above use standard biomechanics (τ=F·d) and known literature values to benchmark human joint loads. We assumed static equilibrium and typical anthropometry as noted. The conclusions highlight how these estimated torques far exceed published human performance and safety limits.