Wednesday, July 26, 2017

Elite Athletes' Bench Press: Few Changes in Pecs, Biceps, Triceps, Delt Muscle Activity W/ Bench Angle + Grip Width

An extreme arch as it can be seen in this female lifter was not allowed in the study at hand. Speaking of female lifters. There were no women among the subjects of the study at hand, but there's also no reason to believe that there are fundamental sex differences in muscle activity.
No, this is not the first article on the effect of bench angle and grip width on one's ability to actually target the pectoralis muscle during the bench press, here at the SuppVersity. It is, however, the first one to be based on data from "elite bench press athletes".

More specifically, the subjects in Saeterbakken's latest study were twelve bench press athletes competing at national and international level (mean age 34.3 ± 14.1 years, body mass 97.6 ± 18.3 kg, stature 1.73 ± 0.12 m | personal best ranged from 130 in a 56kg guy to 240 in an athlete competing in the <82.6kg class). All participants competed in the bench press, four athletes participated in all three competitive powerlifting exercises (bench press, squat, and deadlift).
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As the authors highlight, "[p]revious bench press studies were also limited by [...] testing muscle activation patterns at non-fatiguing, submaximal loads, and applying the criterion of absolute rather than relative intensity when comparing different variations of the bench press action" (Saeterbakken 2017). Needless to say that the scientists from Norway and the UK tried to avoid these shortcomings in their latest study in which the aforementioned 12 athletes did not have to stick to the competition rules, which stipulate a deliberate stop phase in which the barbell rests on the chest, however, participants were instructed that the barbell had to touch the chest gently without any bouncing, before being lifted up to full elbow extension.

All subjects had to perform the bench press at a uniquely intense 6-RM (meaning a weight they could lift for only 6 reps). Each repetition was performed at a self-selected speed and with no pauses between repetitions. The muscle activity was measured by the means of dipolar sliver-silver chloride electrodes (11 mm contact diameter, 20 mm center-to-center distance) that were placed over the center of the muscle belly along in the principal direction of muscle fibers of the pectoralis major (PM) (clavicular and sternocostal part), triceps brachii (TP), biceps brachii (BB), anterior deltoid (AD), posterior deltoid (PD) and latissimus dorsi (LD), using anatomical landmarks and according to the recommendations of SENIAM and similar studies (Hermens et al., 2000).

Data was recorded in a within-participants cross-over design, meaning that each of the subjects had to do all variations of the bench press you will get if you vary the following variables: wide (81 cm spacing between palms), narrow (42.0 ± 3.5 cm) and medium (61.5 ± 3.5 cm) grip width on flat bench, +25º inclined and −25º declined bench.
Difference in bar trajectories between expert and novice strength athletes; mind the sign. difference in the eccentric vs. concentric path in the experts (Madsen 1984).
How's the bench press of a pro different from a novice? Madsen et al. (1984) compared how 19 "expert" and 17 "novice" athletes benched and made some surprising observations: While the experts were obviously able to lift almost 80% more weight, the difference in peak force was comparatively small, with a 43% and a 45% difference on the concentric portion of the move. What is notable, however, is that the experts kept pushing all the way up and thus had 87% higher minimal force values than the novices.

The experts also lowered the bar slower and used a different sequence for lowering and pushing the bar back up, respectively. You can see the difference in the sketches on the left, with the novices using the same path during both portions of the lift, while the experts use a fundamentally different trajectory (bringing the bar further up to the shoulders much earlier in the movement) while raising the bar at an initially low angle of 60° (vs. 80° in novices).
To get decently reliable values, all subjects performed five sets of 6-RM presses (6-RM was tested in a familiarization session) were performed in randomized order for each of the conditions.

The angle of the bench modifies mostly the biceps and triceps activity

Much in contrast to what conventional wisdom and some of the studies in untrained individuals suggest, the pectoralis major (PM | clavicular and sternocostal part) activity, and the activity of the anterior (AD) and posterior deltoid (PD), were similar in all three bench conditions (flat, inclined and declined), albeit with a 25.7% increase in EMG activity in the anterior deltoid when comparing the inclined to the declined position (other differences were not statistically significant).
Figure 1: % changes in muscle activity during incline/decline compared to flat bench presses (Saeterbakken 2017).
An effect of bench angle was observed for the triceps, though; with the inclined bench condition producing a sign. lower EMG muscle activity in the triceps brachii (TB) than the flat (-58.5%) and declined (-62.6%) bench. These differences were statistically highly significant and the effect size was large (p ≤ 0.001–0.001; ES = 1.16–1.28). Differences between the flat and declined bench press were not observed.
Anything else? While it is not clear how the elbow position will affect the strength and hypertrophy effects of the exercise, you may be interested in hearing that the wide-grip decline bench press induced the lowest relative elbow position at the bottom of the movement. Conventional wisdom links this increased stretch to a superior hypertrophy response, but I haven't seen convincing evidence to prove what I'd like to call the "pec-stretch-hypertrophy hypothesis" ... yet(?).

Total volume w/ rest-pause vs. traditional bench press (Korak 2017).
What has been associated with increased gains, though are volume increases (Häkkinen 1987; Ahtiainen 2003; Schoenfeld 2010); volume increases as they have just been observed by Korak et al. (2017) when they compared regular bench pressing with bench pressing using a rest-pause technique. With 56,778 vs. 38,315 lbs, the difference wasn't just statistically significant (p < .05), but also potentially relevant... assuming that you don't do too many sets for chest, anyway (the study used only 4 sets at 80% of the 1RM and you don't need to do decline, incline and flat bench presses with dumbbells and barbells - that's counter-productive madness).
Interestingly enough, the lack of triceps activity seemed to be compensated by significant increases in biceps brachii (BB) involvement - 48.3% and 68.7% greater muscle activation was observed in the inclined bench condition compared with flat and declined, respectively (p = 0.003–0.005, ES = 0.99–1.17). Again, no differences in EMG in BB were observed between the flat and declined bench (p = 0.401). In AD, similar EMG activity was observed between flat and the two inclined bench positions (p = 0.377–1.000), a 25.7% greater EMG activity was observed when performing in the inclined compared to the declined bench position (p = 0.002; ES = 0.50).

Changing grip width modifies only the recruitment of the biceps muscle

In contrast to conventional wisdom, changing the grip width did not affect the involvement of the triceps (neither did it change the pectoralis or deltoid activity).
Figure 2: % changes in muscle activity with medium/narrow compared to wide grip (Saeterbakken 2017).
Using a narrow grip did, however, reduce the activation of the biceps brachii (BB) by 30.5% and 25.9% compared to the medium and wide grip, respectively - the effect size was small, though (p = 0.003–0.040, ES = 0.25–0.33).

The study confirms the previously reported effects of bench angle on maximal weight

You will remember that from the SuppVersity EMG Series: The decline bench press will allow you to lift the most weight. That's also what the Norwegian researchers observed in the study at hand, in which "[t]he 6-RM load in the inclined bench condition (109.2 ± 11.1 kg) was 21.5% lower than in the flat condition (132.7 ± 17.1 kg) and 18.5% lower than in the declined condition (129.4 ± 13.7 kg, p ≤ 0.001, ES = 1.62 –1.63)" (Saeterbakken 2017). The difference between the flat and declined position, on the other hand, failed to reach statistical significance (p = 0.212).

The greatest weights were lifted with the wide grip (note: this is the angle the subjects were used to bench with. Therefore, I wouldn't want to guarantee that there's not simply a training effect involved, here) -- 5.8% and 11.1% greater 6-RM loads were achieved in the wide grip condition (132.7 ± 17.0 kg) compared to the medium (125.4 ± 17.4 kg) and narrow grip (119.2 ± 16.6 kg), respectively (p ≤ 0.001, ES = 0.42–0.80). The fact that a greater 6-RM load was achieved using a medium grip compared with a narrow grip (p = 0.016, ES = 0.36) is likewise in line with previous research consistently showing that a narrow grip will allow people to lift the least weight.
EMG Study Can Tell Us Something About Using Dumbbells, Barbells and Machines During Chest & Triceps Workouts | read full article
What are the practical implications? At least for highly trained subjects, some of the 'common wisdoms' of bench pressing have been busted with the study at hand: (1) A narrow(er) grip won't increase triceps activation, (2) the angle of the bench has a marginal effect on the involvement of the deltoids and (3) the biceps is doing more work than you'd probably imagined - especially with a wider grip.

The study does seem to confirm, however, that people are strongest using a wide grip, which is thus your best choice if you want to impress someone with "how much ya bench".

It should be noted, though, that the "wide" grip in the study at hand was identical to the grip width prescribed in powerlifting - the fact that the subjects were used to bench like this may thus have affected the results. Moreover, it should be kept in mind that the "narrow" grip was significantly wider than what the average gymrat would consider a "narrow grip" - accordingly, one must regard (1) with caution; previous studies showed quite convincingly that a really narrow grip will induce significant increases in triceps activation (especially if you don't flare your arms out) | Comment on Facebook!
References:
  • Ahtiainen, Juha P., et al. "Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men." European journal of applied physiology 89.6 (2003): 555-563.
  • Häkkinen, K., et al. "Relationships between training volume, physical performance capacity, and serum hormone concentrations during prolonged training in elite weight lifters." International Journal of Sports Medicine 8.S 1 (1987): S61-S65.
  • Hermens, Hermie J., et al. "Development of recommendations for SEMG sensors and sensor placement procedures." Journal of electromyography and Kinesiology 10.5 (2000): 361-374.
  • Korak, et al. "Effect of rest-pause vs. traditional bench press training on muscle strength, electromyography, and lifting volume in randomized trial protocols. Eur J Appl Physiol. 2017 Jul 12. doi: 10.1007/s00421-017-3661-6. [Epub ahead of print]
  • Madsen, N. E. L. S., and T. H. O. M. A. S. McLAUGHLIN. "Kinematic factors influencing performance and injury risk in the bench press exercise." Medicine and science in sports and exercise 16.4 (1984): 376-381.
  • Schoenfeld, Brad J. "The mechanisms of muscle hypertrophy and their application to resistance training." The Journal of Strength & Conditioning Research 24.10 (2010): 2857-2872.
  • Saeterbakken, Atle Hole, et al. "The Effects of Bench Press Variations in Competitive Athletes on Muscle Activity and Performance." Journal of Human Kinetics 57.1 (2017): 61-71.