A program may record load, grip width, and tempo precisely while saying little about the bench. Yet its height, width, contour, firmness, and traction help define the task the lifter performs.
Bench-press mechanics emerge from the interaction of the lifter, bar and support surface. The feet meet the floor, the hands meet the bar and the posterior torso meets a surface with specific height, width, contour, edge, friction and compression. Together, these interfaces define the task the lifter performs.
The central AMM interface framework
Three Contact Points Shape the Repetition
- 1 · Hands / barGrip and external load
- 2 · Torso / benchShape, contact and support
- 3 · Feet / floorPosition and contact
The bench is one of three contacts that define the repetition. Numbered markers identify the interfaces: hands on the bar, torso on the bench and feet on the floor.
Position · contact · friction · ground reaction
Grip · wrist · vertical and horizontal force
Support · geometry · pressure · friction
Path · force · range · velocity · activation · repeatability
The framework makes the support condition explicit so it can be documented and tested alongside the other contacts. Article 02 explains the bench’s engineering specification. Here, the focus is the full interface and the progression from acute testing to training studies.
Feet → Floor
Foot position, contact and floor friction influence lower-body tension and pelvic position. Gardner and colleagues compared standard, leg-drive and feet-up conditions in 27 participants at 75% of the standard-condition 1RM. Ground-reaction-force data confirmed that the lower-body conditions differed.[1]
Evaluate the feet-to-floor interface with measures relevant to the question: foot pressure or ground force for the base, bar and body motion for technique, and performance for output.
Hands → Bar
Mausehund and colleagues tested 35 strength-trained adults across four grip-and-elbow conditions. Conditions differed by as much as 12% in load; shoulder net moments increased by as much as 43% with wider grips, while elbow moments increased by as much as 26% as grip narrowed.[2]
Larsen and colleagues separately compared 1RM presses at grip widths of 1.0, 1.4 and 1.7 times bi-acromial width in 14 experienced men. Mean loads were 103.7, 108.9 and 109.8 kg from narrow to wide, vertical displacement increased as grip narrowed and horizontal force direction changed across conditions.[3] The bar travels mainly upward, but the interface has direction as well as magnitude.
Torso → Bench
The posterior boundary can be described by contact location, contour, width, edge clearance, friction, compliance and effective height. Friction describes resistance to sliding, and compliance describes compression under load; both can vary across athletes. These properties can be documented directly.
Goodman and colleagues compared flat-bench and exercise-ball conditions in 13 participants, measuring 1RM, muscle activation and elbow range of motion under their protocol.[4]
The useful comparison is whether a defined surface change produces a measured difference under a defined protocol.
Observation → hypothesis → controlled test
What to Record About the Bench Surface
During Launch Pad development, AMM used a clear acrylic flat-bench demonstration to make posterior contact easier to see. The demonstration can reveal where an athlete appears to contact or clear a surface and can help designers formulate questions about contour, edges and torso position.
Observing Contact Through an Acrylic Bench
From a visible boundary to a measurable condition
Matching Support to the Lifter and Task
A competition bench standardizes setup so performances can be compared, and familiar geometry can make the setup easier to reproduce. How an edge or contour interacts with a lifter depends on the task and measured outcome.
Friction can influence whether an athlete holds a selected position. Assess it by recording setup error, position drift, pressure distribution or bar outcomes across repeated trials. Characterize compliance by measuring unloaded thickness, compression under representative loads, recovery and athlete-to-athlete variation.
A useful interface record can be short: surface or insert, bench height, pad angle, rack height, contact configuration, grip, foot position and any setup cue that materially affects the repetition. Use the same record across trials to compare setup conditions and outcomes.
Direct evidence · stage 01
The Acute Crossover: Did the Repetition Change?
Kidwell and colleagues recruited 10 resistance-trained men (23 ± 3 years) for a randomized, single-blind crossover. In separate sessions approximately 48 hours apart, participants performed five repetitions on a conventional flat bench and with the Launch Pad at 70% of each participant’s established 1RM. Hand position was standardized to 150% of bi-acromial width.[5]
AMM Research · Study results · Kidwell et al. (2026)
Six acute outcomes, shown side by side
Bars show condition means with SD error bars. Each outcome uses its own units; all axes start at zero. Study source [5].
Right pectoralis sEMG
Flat bench: 70.2 ± 24.8 % MVC · Launch Pad: 87.3 ± 20.1 % MVC
p < .001 · d = .76
Left pectoralis sEMG
Flat bench: 68.3 ± 23.4 % MVC · Launch Pad: 86.8 ± 20 % MVC
p < .001 · d = .85
Mean bar velocity
Flat bench: 0.40 ± 0.09 m/s · Launch Pad: 0.47 ± 0.09 m/s
p < .001 · d = .74
Peak bar velocity
Flat bench: 0.57 ± 0.11 m/s · Launch Pad: 0.66 ± 0.09 m/s
p < .001 · d = .98
Vertical displacement
Flat bench: 38 ± 7 cm · Launch Pad: 44 ± 4 cm
p = .005 · d = 1.02
Concentric power
Flat bench: 249 ± 103 W · Launch Pad: 271 ± 93 W
p = .071 · d = .23
The figure shows the raw condition means for the measured muscle-activity and bar outcomes. Percentage differences are calculated from those means. Together, the results show how the tested support condition changed a submaximal set.
Direct evidence · stages 02 and 03
Repeated Exposure: Two Randomized Training Trials
42 intermediate-trained men were randomized to eccentric-overload training with the Launch Pad or a matched flat condition. Both groups used the same CARE machine protocol.
AMM Research · Training trial · Visual 26
Strength gain after four weeks
Bars show mean changes from baseline; error bars show SD. Both groups followed the same eccentric-overload protocol. Study source [6].
1RM change
Control: +11.1 ± 2.4 kg · Launch Pad: +18.4 ± 4.3 kg
7.3 kg between-group difference · p < .001 · g = 3.85
The Launch Pad group’s mean gain was approximately 66% larger. That percentage is derived from the two raw group means.[6]
30 male collegiate football players were randomized in the off-season to Launch Pad or conventional-bench training within the same program.
AMM Research · Training trial · Visual 27
Strength and performance after eight weeks
Bars show mean changes from baseline. The 1RM error bars show SD; the other two charts show means only. Study source [7].
1RM change
Control: +9.7 ± 3.4 kg · Launch Pad: +19.4 ± 4.3 kg
p < .001 · g = 3.99
NFL-225 repetitions
Control: +4 reps · Launch Pad: +7 reps
Between-group p < .001
Bars show group mean changes.
Seated medicine-ball throw
Control: +2.0 m · Launch Pad: +2.7 m
Between-group p < .001
Group mean changes are shown.
The three randomized trials report acute repetition outcomes and strength or performance changes over four and eight weeks across their respective populations and protocols.
How the evidence fits together
How the Studies Relate
-
ObservationDesign observation
Make contact visible
Acrylic demonstration documents visible contact and helps form hypotheses.
-
Acute testDirect acute evidence
Change one support condition
Crossover protocol measures same-participant differences in selected repetition outcomes.
-
Four-week trialDirect training evidence
Repeat exposure
Randomized eccentric-overload program tests short-term 1RM adaptation.
-
Eight-week trialDirect training evidence
Replicate in a team setting
Randomized football program tests strength, repetition and throw outcomes.
Published:three Launch Pad studies report acute and longitudinal outcomes under defined protocols.Active:Joint Ops™ prototype testing is underway.
Joint Ops™ moves the posterior interface from an added support condition into the bench architecture itself through selectable torso surfaces, shoulder-clearance intent, adjustable lumbar positioning, seat geometry, traction, stability and mechanical indexing. The prototype makes these variables directly testable, and existing biomechanics helps frame the research questions. The project page carries the current research status.
For repeatability, record the support condition alongside load, grip, angle, rack height and other setup variables. Test one interface change at a time, then use the record to connect setup conditions with outcomes.
Next in the research sequence · the shoulder-mechanics articleMove from the interface record to anatomy, kinematics, kinetics, muscle activity and clinical meaningReferences
- Gardner JK, Chia JT, Miller KL. (2019). Leg-drive does not affect upper extremity muscle activation during a bench press exercise. International Journal of Human Movement and Sports Sciences, 7(1), 12–17. doi:10.13189/saj.2019.070103. ↩
- 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. ↩
- Larsen S, Gomo O, van den Tillaar R. (2021). A biomechanical analysis of wide, medium, and narrow grip width effects on kinematics, horizontal kinetics, and muscle activity on the sticking region in recreationally trained males during 1-RM bench pressing. Frontiers in Sports and Active Living, 2, 637066. doi:10.3389/fspor.2020.637066. ↩
- Goodman CA, Pearce AJ, Nicholes CJ, Gatt BM, Fairweather IH. (2008). No difference in 1RM strength and muscle activation during the barbell chest press on a stable and unstable surface. Journal of Strength and Conditioning Research, 22(1), 88–94. doi:10.1519/JSC.0b013e31815ef6b3. ↩
- Kidwell JA, Yamamoto T, Hetherton KJ, 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. ↩
- Goldman P, Taylor J, Yamamoto T, et al. (2025). Eccentrically overloaded bench press training: Augmenting strength gains via a novel bench press pad. Scientific Journal of Sport and Performance, 4(4), 480–490. doi:10.55860/JCDL3612. ↩
- Blatney AE, Kidwell JA, Yamamoto T, Goldman P, Hetherton KJ, Dolezal BA. (2026). Effects of an eight week training regimen with a novel bench press pad compared to a traditional bench on upper body strength and performance in collegiate American football players. Scientific Journal of Sport and Performance, 5(1), 10–21. doi:10.55860/RNUB8627. ↩