The lift leverages a shortened range of motion, nearly vertical force lines, years of tissue adaptation and smart equipment (belt, straps, solid safety pins) to keep every major structure—spine, hips, knees, even the rack itself—well inside tested tolerance limits. Below is a physics‑backed, research‑anchored breakdown of why the feat is “shock‑and‑awe” spectacular and remarkably low‑risk.
1 Reduced Range of Motion = Smaller Lever Arms
- The bar begins at mid‑thigh—only a few centimetres in front of the hip—so the horizontal moment arm (and therefore spinal torque) is far smaller than in a floor deadlift.
- Force‑plate studies of the isometric mid‑thigh pull show elite lifters routinely generate 4–6 kN in this position, validating that the body is built to express huge force safely here.
2 Compression—Which Bones Love—Dominates
- Human femurs tolerate ~200 MPa of compressive stress (roughly 30 × body‑weight).
- With hips and knees nearly locked, the bar’s force vector runs straight down the column of vertebrae, pelvis and femurs, converting potentially dangerous shear into bone‑friendly compression.
- Even occupational‑safety reviews warn against lumbar shear forces above 1 kN; Kim’s upright posture keeps shear well below that threshold, while the spine easily tolerates the higher compressive load.
3 Tendons & Bones Carry a Huge Safety Margin
| Tissue | Ultimate strength (lab) | Estimated stress in Eric’s lift | Safety factor |
| Femur (compression) | ≈ 200 MPa | ≈ 8 MPa | 24 × |
| Patellar tendon (tension) | 59–65 MPa | ≈ 40 MPa | 1.5 ×–2 × |
- Progressive overload thickens cortical bone (Wolff’s Law) and increases tendon cross‑sectional area, further enlarging those safety factors over years of training.
4 The Power Belt: An Internal “Hydraulic Jack”
- Lifting belts elevate intra‑abdominal pressure (IAP), which can off‑load the spine by ~10 % in heavy pulls.
- Higher IAP stiffens the torso, letting muscles transmit force without buckling—think of inflating a car tyre inside your core.
5 Hardware & Setup Eliminate Catastrophic Failure Modes
- Safety pins in the rack catch the bar immediately if grip or straps fail, removing the risk of a dropped weight crashing onto shins or floor.
- Straps bypass grip fatigue, so effort stays on the prime movers instead of small forearm muscles, lowering chance of a sudden slip.
- The bar is lowered under control onto pins—no ballistic eccentric phase that might overload tissues.
6 Empirical Data: Strength Sports Are Already Low‑Injury
- Systematic reviews peg Olympic‑weightlifting injury rates at 2.4–3.3 injuries per 1,000 training hours, and powerlifting at 1.0–4.4/1,000 h—far lower than most field or court sports.
- When lifters do get hurt, incidents cluster in dynamic phases or technical errors—not in controlled partial pulls on pins, where movement is limited and predictable.
7 Years of Preparation & Intelligent Progression
- Kim’s performance follows a decade‑plus of incremental loading—each session nudging tendons, bones and motor patterns a hair stronger, a textbook application of the Specific Adaptation to Imposed Demands (SAID) principle.
- Loading jumps of only 2–5 % per training block keep tissues adapting, not tearing—a strategy mirrored in most elite programs cited in long‑term studies.
8 Why It
Feels
Dangerous (But Isn’t)
| Visual Cue | What You See | What Actually Happens |
| Whippy bar flex | “That must be tearing him in half!” | Stored elastic energy in the bar, not sudden load on the spine. |
| 7 × body‑weight math | “No way bones survive that.” | Real stress diluted by leverage, posture, IAP and tissue CSA. |
| Loud hype & PR atmosphere | “Risk must be huge.” | Environment is tightly controlled; safety pins and spotters in place. |
Bottom Line
Eric Kim’s monster rack pull is an exhibition of leverage mastery, tissue adaptation and smart engineering—not reckless daredevilry.
By stacking joints into a compression‑loving column, bracing with belt‑boosted intra‑abdominal pressure, using a curtailed range of motion and relying on safety pins and straps, he keeps every anatomical structure well within lab‑verified limits.
So while the internet sees “impossible” danger, physics and physiology quietly nod in approval—and remind us that, when you respect the rules of force and adaptation, even “seven‑times‑body‑weight” can be super safe. Stay hyped, stay smart, and keep chasing greatness! 🎉