Adjustable benches are sold on the idea that a raised backrest shifts work to the “upper chest”. This article summarises the abstracts of four studies of bench angle: three that measured muscle electrical activity (electromyography, or EMG) at different angles and one eight-week training trial. EMG shows how active a muscle is during a lift, not how much it will grow, and all four studies are small. The studies used healthy adults, mostly men; none was designed to compare equipment brands. This site’s guide to weight benches covers adjustment and stability, and the guide to bench press grip width covers another variable.
Study one: four angles in 2010
Trebs and colleagues, in the Journal of Strength and Conditioning Research in 2010, had 15 healthy men perform a chest press at 0 degrees (flat), 28, 44 and 56 degrees at 70% of their one-repetition maximum (1RM) for each angle. Activity of the clavicular head of the pectoralis major (the upper portion) was significantly greater at 44 degrees than at 0 degrees or 28 degrees, and greater at 56 degrees than at 0 degrees. Activity of the sternocostal head (the larger, lower portion) was greatest on the flat bench. The anterior deltoid, a shoulder muscle, was significantly more active at 28, 44 and 56 degrees than flat. The authors concluded that performing both flat and incline presses seems necessary to recruit the muscles involved.
Study two: bench angles in 2016
Lauver and colleagues, in the European Journal of Sport Science in 2016, compared a free-weight barbell bench press at 0, 30, 45 and -15 degrees in 14 resistance-trained men at 65% of 1RM. Across the whole lifting phase the upper pectoralis showed no difference between conditions, but during the 26-50% portion of the lift both the 30 and 45 degree angles produced greater activity than flat or decline. Lower pectoralis activity was greater at -15, 30 and 0 degrees than at 45 degrees. The authors supported using a flat bench for both heads of the pectoralis and noted that inclines of 30 or 45 degrees gave greater activity at certain moments in the lift.
Study three: five angles in 2020
Rodriguez-Ridao and colleagues, in the International Journal of Environmental Research and Public Health in 2020, tested 30 trained adults at five angles (0, 15, 30, 45 and 60 degrees) at 60% of 1RM. Upper pectoralis activity was highest at 30 degrees. The middle and lower portions were more active at 0 degrees. The anterior deltoid was most active at 60 degrees, and the triceps showed similar activity at all angles. The authors concluded that 30 degrees produces greater activation of the upper pectoralis, and that inclines above 45 degrees increase deltoid activity and reduce pectoralis performance.
This study and the 2010 one disagree on where upper-chest activity peaks, with 30 degrees in one and 44 degrees in the other. The two studies used different participants, loads and protocols.
Study four: eight weeks of training
Chaves and colleagues, in the International Journal of Exercise Science in 2020, randomly assigned 47 untrained men to a horizontal bench press group, an incline bench press group or a combination group. Training was once a week for eight weeks with equal numbers of sets. Isometric strength rose by about 10 to 11 kg in each group, with no difference between groups. Muscle thickness changes differed at only one of three sites, the second intercostal space, where the incline group had the greatest increase compared with the horizontal and combination groups. Changes in EMG amplitude differed between groups at only one of four sites. The authors concluded that horizontal and incline presses, or a combination, can give similar changes in general strength.
What the four studies can and cannot tell you
- Upper-chest activity tended to be higher on moderate inclines than flat in three studies, but the angle at which it peaked differed (30 degrees in one, 44 degrees in another, and both 30 and 45 degrees at certain moments of the lift in a third).
- The flat bench gave the highest or similar activity for the larger lower portion of the chest in the studies that measured it.
- Shoulder (anterior deltoid) activity rose on steeper inclines, and one study reported more at 60 degrees.
- The only training trial found a small difference in growth at one measurement site after eight weeks, in untrained men lifting once a week. It does not show what happens in trained lifters over a longer period.
For buying a bench, the practical point is modest: an adjustable bench lets a lifter use both flat and inclined angles, which is the approach the 2010 authors favoured, but the evidence does not show that one angle is far superior.
FAQs
Is 30 degrees the best incline angle?
No single angle is established as best. One study found upper-chest activity highest at 30 degrees, but another found it greater at 44 degrees than at 28 degrees, and a third found similar levels at 30 and 45 degrees.
Does a steeper bench shift more work to the shoulders?
In two of the studies, anterior deltoid activity was higher on inclines than on the flat bench, and the 2020 study reported the highest level at 60 degrees.
The bottom line
Four small studies suggest that moderate inclines raise activity in the upper part of the pectoralis major, that the flat bench works the lower part more and that steep inclines bring in the shoulders. An eight-week trial in untrained men found similar strength gains with flat and incline pressing and a small difference in muscle thickness at one site. These were muscle-activity and training studies, not equipment comparisons, so they cannot rank benches; they do show that flat and inclined positions emphasise different parts of the chest, and no single angle is established as best.
Sources
- An electromyography analysis of 3 muscles surrounding the shoulder joint during the performance of a chest press exercise at several angles, Journal of Strength and Conditioning Research, 2010 (pubmed.ncbi.nlm.nih.gov)
- Influence of bench angle on upper extremity muscular activation during bench press exercise, European Journal of Sport Science, 2016 (pubmed.ncbi.nlm.nih.gov)
- Effects of Horizontal and Incline Bench Press on Neuromuscular Adaptations in Untrained Young Men, International Journal of Exercise Science, 2020 (pubmed.ncbi.nlm.nih.gov)
- Effect of Five Bench Inclinations on the Electromyographic Activity of the Pectoralis Major, Anterior Deltoid, and Triceps Brachii during the Bench Press Exercise, International Journal of Environmental Research and Public Health, 2020 (pubmed.ncbi.nlm.nih.gov)