Spinal Positioning & Force Transfer in the Bench Press

Broader scientific context

What can an arch reveal about support and force?

Arching changes torso position, contact with the bench and the bar’s travel. Compare setups through their effects on control, load, velocity and repeatability.

Back to Shoulder Mechanics

Leg drive and upper-back positioning organize the lifter against the floor, bench and bar. An arch combines thoracic and lumbar extension, pelvic position and scapular setup; those components can differ between athletes with similar-looking arches.

This article follows that support chain and the bench studies that measured its effects. The Athlete-to-Bench Interface covers the full Launch Pad research sequence; Shoulder Mechanics & Bench Press Surface Design examines shoulder loading.

Configuration record · name what changed

Describe the Arch by Region and Contact

A bench-press arch usually describes elevated thoracic geometry and reduced bar travel, but two visually similar arches can distribute motion differently. A complete description should distinguish thoracic position, lumbar position, pelvic orientation, shoulder-girdle setup, head and buttocks contact, foot placement and the distance between the bar and torso.

Visible geometryTorso elevation, bar-to-chest distance, joint positions and bar path.
Contact stateFeet–floor, buttocks–bench, upper back–bench, head–bench and hands–bar.
Force recordGround reaction, bench reaction, vertical and horizontal bar force, net joint moments and timing.
Clinical recordSymptoms, function and tolerance during and after pressing.

The 2026 IPF rulebook defines the competition boundary: during the lift, the lifter’s head, shoulders and buttocks must remain in contact with the bench surface and the feet must remain flat on the platform or blocks.[1]

Practitioner context: Tate and Simmons on the pressing base

Practitioner systems treat these contacts as one setup problem. Dave Tate’s EFS Bench Manual coordinates foot position, upper-back and lat tension, shoulder-blade position and pressure through the upper back as a repeatable pressing base.[2] Louie Simmons’ Westside manual likewise varies foot position, arch, grip, upper-back and lat strategy in service of the lift.[3]

System map · follow every boundary

How the Feet, Bench, and Bar Share the Task

01Foot–floorPlacement, friction and ground reaction create the base.
02Legs + pelvisHip and knee actions can change pressure and whole-body position.
03Lumbar regionRecord lower-back position as part of the torso setup.
04Thorax–benchContact, friction and compression resist drift and establish support.
05Shoulder–armScapular pose, humeral motion and joint moments redistribute the task.
06Hands–barVertical and mediolateral forces determine the external bar interaction.

The floor, bench and bar constrain the lifter at the same time. Assess force transfer through defined outcomes: torso drift, pressure distribution, force direction, load, bar velocity or setup repeatability.

Operational definition · choose an endpoint

What would “better force transfer” look like in a record?

01

Less movement at the support

Torso drift and contact repeatability.

02

A different external strategy

Pressure distribution and three-dimensional force direction.

03

A different test result

Load, bar velocity and repeatability under defined conditions.

Choose the outcome that matches the training or testing goal.
Leg drive and torso position

Foot force may help maintain torso position, change pressure against the bench, limit drift or improve touch-point consistency. Evaluate those changes with synchronized contact, force and movement measurements.

Horizontal forces matter. Mausehund and colleagues showed that omitting lateral barbell forces can materially alter calculated shoulder and elbow net moments during bench pressing.[4] A vertical-only bar trace cannot reconstruct the complete upper-extremity force strategy.

Arch record · compare protocols, not silhouettes

How Arching Changes the Press Across Three Studies

Protocol matters · two 1RM comparisons

A visible arch does not guarantee a larger lift

Read each result within its protocol. A guided bar and a free bar create different comparison conditions.

1RM in the Smith-machine comparison

Flat technique115.9 kg

SD 17.9 kg

Arched technique115.7 kg

SD 18.4 kg

kg · bars show means; SD printed separately

García-Ramos et al. · 11 male powerlifters · p = .942; ES = .01. No statistically significant difference. Study [5].

1RM difference: arched minus flat

Arched − flat+4.2 kg

95% CI 0.0 to 8.4 kg

kg · point = reported difference; line = 95% CI

Bartolomei et al. · 15 power athletes · p = .031; ES = .22. The reported CI is retained at its published precision. Study [7].
01

García-Ramos · Smith machine

Natural lumbar arch and moderate scapular retraction compared with a pronounced arch.

02

Bartolomei · free barbell

Flat and arched 1RM tests; subsequent sets used 50%, 70% and 90% of each technique’s own 1RM.

Separate Smith-machine and free-barbell comparisons [5][7].
Read the complete three-study comparison
Study Participants + contrast Measured result Training relevance
García-Ramos et al.
2021		 11 competitive male powerlifters; natural arch/moderate scapular retraction versus pronounced arch. 1RM: 115.9 ± 17.9 versus 115.7 ± 18.4 kg (p = .942; ES = .01); no velocity differences. No performance advantage for the pronounced arch in this Smith-machine comparison.[5]
Cudlip et al.
2022		 20 experienced men; powerlifting arch versus standardized technique at 25%, 50% and 75% of self-reported 1RM. Arch increased latissimus mean/peak EMG; standardized technique produced approximately 8% larger integrated shoulder moments. Arching changed latissimus activity and integrated shoulder moments at submaximal loads.[6]
Bartolomei et al.
2024		 15 highly trained power athletes; flat versus arched technique at 50%, 70% and 90% of respective 1RM. Arched 1RM was 4.2 kg higher (95% CI 0.0–8.4; ES .22). Flat produced greater displacement and slightly higher mean/peak velocity; power did not differ. A small 1RM advantage accompanied shorter bar travel in these trained athletes.[7]

Bartolomei et al. · displacement

The travel difference depends on the load

Extra bar displacement with the flat technique

50% of respective 1RM+47 mm

95% CI 34.0 to 61.0 mm

70% of respective 1RM+40 mm

95% CI 24.0 to 55.0 mm

90% of respective 1RM+28 mm

95% CI 6.0 to 50.0 mm

mm · point = reported difference; line = 95% CI

Flat minus arched at each relative load. These are between-technique differences, not absolute travel distances. Study [7].
Loads were calculated from each technique’s own 1RM [7].

Pinto and Dickerson add a geometric mechanism: in 20 men tested at 25%, 50% and 75% 1RM, an arched technique reduced vertical bar displacement by about 11% and the bar-to-glenohumeral-joint moment arm by about 20%.[8] The shorter moment arm helps explain the change in external mechanical advantage.

Arching can change bar travel, muscle activity and measured performance. The effect depends on the comparison technique, the lifter’s proficiency, the load and the outcome measured.

Bar Movement and Internal Loading

Measuring Bar Performance and Internal Tissue Load

AMM Research · Visual 15 · contact and measurement

Visible posture does not resolve internal loading

Illustrated side view of a lifter pressing a barbell on a flat bench, with head, upper back and buttocks supported and both feet planted on the floor.
01

Hands ↔ bar

Measure vertical and mediolateral force components alongside bar position and time.

02

Body ↔ bench

Record contact, pressure or reaction force with a defined method.

03

Feet ↔ floor

Record foot placement and floor reactions.

External record

Contacts + motion + forces

Synchronized measurements describe the external task.

Internal estimate

Regional inputs + model

Internal loading estimates depend on model assumptions and measured inputs.

Clinical record

Separate outcomes

Track symptoms, function and tolerance over repeated exposures.

Illustrative bench-press posture showing contacts with the bar, bench and floor. Internal-loading estimates combine measured motion and forces with a model [4].
Observable or directly measurable

Contact points · bar displacement · bar velocity · external load · ground/bench/bar forces · surface EMG · whole-body and segment kinematics · performance reliability.

How inverse dynamics, models and surface EMG work

Inverse dynamics and musculoskeletal models estimate joint moments or selected reaction forces from measured inputs and model assumptions. Surface EMG records electrical activity from the sampled muscles, while bar velocity describes the external performance outcome. Internal force transmission requires additional measurements and modeling.

Field audit · make setup reproducible

What Coaches Can Record Before Drawing Conclusions

Base

Feet and floor

Record foot position, heel contact, block use and slipping.

Pelvis

Buttocks contact

Record whether and where contact is maintained, plus any visible shift during unrack and press.

Torso

Thoracic and lumbar setup

Use consistent landmarks or video views to compare thoracic and lumbar position.

Upper back

Contact and drift

Record scapular cue, surface position and movement relative to pad markings or indexed settings.

Bar

Path and force direction

Track touch point, vertical travel, velocity and, when researching mechanics, horizontal force.

Response

Performance and tolerance

Record load, repetitions, exertion and symptoms during and after.

For coaching, this audit makes setups comparable. For research, it defines covariates and independent variables. For persistent pain, neurological symptoms, postoperative restrictions or return-to-sport decisions, it does not replace clinical assessment.

Launch Pad design and research

Support Geometry Changes the Pressing Task

Inventing The Launch Pad connects shoulder clearance, lumbar support, leg drive and stability as one equipment-design problem.[9] The acute study below tested how the changed support affected bar travel and velocity.

Kidwell et al. · 2026 · Table 1

The external outcomes, side by side

  • 10 trained men
  • 70% 1RM
  • 5 repetitions
  • Randomized crossover

Vertical bar displacement

Flat bench38 cm

SD 7 cm

Launch Pad44 cm

SD 4 cm

cm · bars show means; SD printed separately

p = .005 · bar travel, not spinal motion Study [10].

Mean bar velocity

Flat bench0.40 m/s

SD 0.09 m/s

Launch Pad0.47 m/s

SD 0.09 m/s

m/s · bars show means; SD printed separately

p < .001 Study [10].

Peak bar velocity

Flat bench0.57 m/s

SD 0.11 m/s

Launch Pad0.66 m/s

SD 0.09 m/s

m/s · bars show means; SD printed separately

p < .001 Study [10].

Concentric power

Flat bench249 W

SD 103 W

Launch Pad271 W

SD 93 W

W · bars show means; SD printed separately

p = .071 · no statistically significant difference Study [10].
Four acute bar-performance outcomes, with means, SDs and p-values [10].
Read the original numerical findings in full

In the published Launch Pad randomized crossover, 10 resistance-trained men performed five repetitions at 70% of established 1RM. The support condition increased mean vertical bar displacement from 38 ± 7 to 44 ± 4 cm (p = .005), mean velocity from 0.40 ± .09 to 0.47 ± .09 m/s and peak velocity from 0.57 ± .11 to 0.66 ± .09 m/s (both p < .001). Concentric power was not significantly different: 249 ± 103 versus 271 ± 93 W (p = .071).[10]

For coaching, use The Launch Pad®’s torso and lumbar support to establish a repeatable position, then assess bar travel, control and load from that setup. Record any change in torso drift or touch point alongside performance.

Research path · return to the evidence spineRevisit the Athlete-to-Bench Interface for the complete direct Launch Pad study progression

References

  1. International Powerlifting Federation. (2026). Technical Rules Book, effective March 1, 2026, version 3. Official rulebook. ↩
  2. Tate D. (2008). EFS Bench Manual. elitefts, pp. 8, 12. Practitioner source supplied for this review. Related official elitefts article. ↩
  3. Simmons L. (2009). Westside Barbell Bench Press Manual. Westside Barbell, pp. 24–28. Practitioner source supplied for this review. Official manual page. ↩
  4. Mausehund L, Werkhausen A, Bartsch J, Krosshaug T. (2022). Understanding bench press biomechanics—The necessity of measuring lateral barbell forces. Journal of Strength and Conditioning Research, 36(10), 2685–2695. doi:10.1519/JSC.0000000000003948. ↩
  5. García-Ramos A, Pérez-Castilla A, Villar Macias FJ, Latorre-Román PÁ, Párraga JA, García-Pinillos F. (2021). Differences in the one-repetition maximum and load–velocity profile between the flat and arched bench press in competitive powerlifters. Sports Biomechanics, 20(3), 261–273. doi:10.1080/14763141.2018.1544662. ↩
  6. Cudlip AC, Maciukiewicz JM, Pinto BL, Dickerson CR. (2022). Upper extremity muscle activity and joint loading changes between the standard and powerlifting bench press techniques. Journal of Sports Sciences, 40(9), 1055–1063. doi:10.1080/02640414.2022.2046937. ↩
  7. Bartolomei S, Caroli E, Coloretti V, Rosaci G, Cortesi M, Coratella G. (2024). Flat-back vs. arched-back bench press: examining the different techniques performed by power athletes. Journal of Strength and Conditioning Research, 38(7), 1200–1205. doi:10.1519/JSC.0000000000004778. ↩
  8. Pinto BL, Dickerson CR. (2021). Vertical and horizontal barbell kinematics indicate differences in mechanical advantage between using an arched or flat back posture in the barbell bench press exercise. International Journal of Sports Science & Coaching, 16(3), 756–762. doi:10.1177/1747954120982954. ↩
  9. Advanced Muscle Mechanics. Inventing The Launch Pad. Historical design article, reviewed August 2026. Original AMM article. ↩
  10. Kidwell JA, Yamamoto T, Hetherton KJ, Truneh N, Bright JJ, Blatney AE, et al. (2026). Acute effects of thoracic-spinal elevation via a novel bench press pad on sEMG and barbell kinetics in resistance-trained males. International Journal of Exercise Science, 19(1), 1003. doi:10.70252/IJES2026103. ↩