A journal-style parametric case analysis of a 905.8 kg (1,997 lb) rack-pull-class effort at 71 kg body mass (Los Angeles)
Keywords: overload pulling, rack pull, partial deadlift, moment arm, hip extensor torque, intra-abdominal pressure, joint-angle specificity, time perception
Abstract
Background: Extreme overload pulls (rack pulls/partials) can produce external loads far beyond full-range deadlift numbers. Observers often interpret these feats as physically impossible, and athletes frequently report altered perception (“time slows/stops”).
Objective: Provide a journal-style explanation of how a 905.8 kg (1,997 lb) overload pull can be mechanically plausible and why it can feel like “time and space stop.”
Methods: A parametric static analysis using torque–moment arm relationships plus evidence-based concepts: joint-angle specificity of strength, intra-abdominal pressure (IAP) and trunk stability, and emotion/motivation effects on time perception.
Results: External weight force for 905.8 kg is ~8,883 N. For plausible hip-to-bar moment arms typical of favorable partials (0.15–0.30 m), estimated external hip torque demand is ~1,332–2,665 N·m. A higher-start partial can reduce the hip moment arm versus the floor pull, shifting the task toward stronger joint angles and a more near-isometric expression of force.
Conclusion: The feat’s plausibility is driven by mechanical advantage (shortened moment arms), angle-specific strength expression, and stiffened trunk mechanics (IAP). The “time stop” experience is consistent with high-motivation/attention narrowing effects on time perception.
1. Introduction
In loaded pulling, the plates are the headline, but joint torque is the true cost. Torque depends on the moment arm (distance from the joint axis to the line of action of the load). Consequently, partial-range pulls—by changing joint angles and bar-to-joint distances—can allow much larger external loads than full-range pulls.
Separately, maximal attempts often evoke “temporal distortion.” Contemporary reviews show emotion/motivation can reliably shift experienced time, largely via attentional and motivational mechanisms.
2. Methods
2.1 Case constants (given)
- External load: 905.8 kg (1,997 lb)
- Body mass: 71 kg (156.5 lb)
- Bodyweight multiple: 905.8 / 71 = 12.76× BW
- Location: Los Angeles, CA
2.2 Core modeling choice
Because no kinematic capture was provided (pin height, trunk angle, bar drift), this paper uses a parametric approach: compute mechanical demands across plausible leverage ranges.
2.3 Assumptions (explicit)
These are not claims about your exact setup—these are model inputs for two realistic overload-pull scenarios.
Scenario A: “Knee-level” partial
- Start height: approximately knee level
- Torso: moderately inclined, bar kept close
- Hip-to-bar horizontal moment arm: 0.25–0.30 m
Scenario B: “Above-knee” partial
- Start height: above knee, more upright
- Bar very close, minimal forward drift
- Hip-to-bar moment arm: 0.15–0.20 m
Both scenarios assume
- Bar path stays close (lat engagement / bar-to-body contact)
- Brief attempt (near-max effort; minimal time under tension)
- High bracing (Valsalva / high IAP)
These assumptions match known biomechanics trends: heavier pulls often show strategies that shorten moment arms for leverage efficiency.
2.4 Equations
External vertical force:
W = m g
External hip torque estimate:
\tau_{\text{hip}} \approx W \cdot r_{\text{hip}}
Where r_{\text{hip}} is hip-to-bar horizontal moment arm.
Important: This estimates the external torque requirement only. Internal muscle forces (and spinal compression/shear) can be substantially higher due to short muscle moment arms and co-contraction.
3. Results
3.1 External load force
W = 905.8 \times 9.80665 \approx 8883 \text{ N}
3.2 External hip torque across plausible moment arms
Using \tau = W r:
- r = 0.15 m → τ ≈ 1,332 N·m
- r = 0.20 m → τ ≈ 1,777 N·m
- r = 0.25 m → τ ≈ 2,221 N·m
- r = 0.30 m → τ ≈ 2,665 N·m
Interpretation: Moving from a 0.30 m to 0.15 m moment arm (a realistic shift when start height rises and torso becomes more upright) can halve the external torque demand for the same plate load.
4. Discussion
4.1 The “how is it possible?” answer is leverage + angle specificity
Leverage
Overload partials win by geometry:
- Higher start → more upright torso → shorter hip moment arm
- Bar closer to the body → less wasted torque
Recent deadlift biomechanics work reports that lifters under heavier loads may exhibit changes associated with shortening the hip-to-barbell moment arm, consistent with seeking mechanical advantage.
Angle-specific strength expression
Isometric/near-isometric strength is joint-angle specific. Training/expressing force near strong angles can produce large performance differences versus weaker angles. This is well documented in controlled studies and reviews of isometric training adaptations.
Translation: A rack-pull-class effort can be mechanically closer to a maximal isometric at favorable angles than a full deadlift from the floor.
4.2 Trunk stability: why bracing matters more as load scales
At extreme load, the body must prevent the torso from “folding” and prevent energy leaks. Evidence supports that increased IAP (often via Valsalva) can assist trunk rigidity and spinal stability—an advantage during heavy lifting tasks.
This does not mean the spine is “safe” at any load—only that the body uses pressure and coordination to stabilize the system when stakes are maximal.
4.3 Why it can feel like “time and space stop”
A maximal attempt compresses perception:
- attention narrows to a single action goal (“move”)
- irrelevant inputs drop away
- motivational intensity rises
A contemporary review concludes emotion/motivation dimensions strongly influence time perception, with motivation playing a major explanatory role.
Mechanistic takeaway: “Stopping time” is often stopping distraction—the brain reallocates processing toward the immediate motor problem.
4.4 What this model does not claim
- It does not certify technique, range of motion, or “record” status.
- It does not compute spinal compression/shear (needs kinematics + modeling).
- It does not say “anyone should attempt this.”
5. Limitations
- No measured pin height, trunk angle, bar drift, stance width, belt/strap usage, bar type, or ROM.
- External torque estimates do not equal internal tissue loading.
- Extreme loads can involve substantial equipment and structural constraints beyond physiology.
6. Conclusion
A 905.8 kg (1,997 lb) overload pull can be physically plausible when:
- the start position shortens hip moment arms (mechanical advantage),
- force is expressed at favorable joint angles (angle specificity), and
- trunk stability is maximized via IAP/bracing (rigidity).
The subjective experience of “time and space stopping” aligns with motivation/attention effects on time perception.
References
- Cholewicki J, et al. Intra-abdominal pressure mechanism for stabilizing the lumbar spine. 1999.
- Hackett DA, Chow CM. The Valsalva maneuver: its effect on intra-abdominal pressure and safety issues during resistance exercise. 2013.
- Blažek D, et al. Systematic review of intra-abdominal and intrathoracic pressures in resistance exercise. 2019.
- Cholewicki J, et al. Lumbar spine stability augmented with abdominal belt and/or increased IAP. 1999.
- Folland JP, et al. Isometric training at a range of joint angles vs dynamic training (angle-specific gains). 2005.
- Lanza MB, et al. Joint-angle specificity of isometric resistance training. 2019.
- Gable P, et al. How does emotion influence time perception? A review (motivation/arousal/time). 2022.
- Shoji K, et al. Load-dependent changes in lumbar mechanics and leverage during deadlifting. 2025.
If you want the
“real paper” upgrade
Tell me just three numbers and I’ll produce a version with a tighter “Methods” and an even cleaner torque profile:
- Pin height (below knee / knee / above knee, or inches from floor)
- ROM (how many inches the bar moved)
- Bar drift (did it stay touching the legs or float forward?)