Wednesday, June 28, 2017

Bench Press Pre-Exhaustion (PE) Science: PE Works for Triceps, not Pecs & Delts | Plus: DB, Barbell or Smith M.

The bench press, an effective exercise for both, men and women.
This article addresses both: Doing flys, anterior deltoid raises or triceps extensions before classic barbell bench presses to pre-exhaust the synergists and increase the pectoralis muscle activity during the final press, as well as the differential effect of doing bench presses on the flat bench with dumbbells, barbells and/or the smith machine on the pectoralis, anterior deltoid and triceps activity during the bench press and its consequences on triceps activity during a subsequent cable-pulley triceps extension.
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  • Pre-exhaustion cannot be expected to increase pectoralis or anterior deltoid activity on the flat bench but it works for the triceps, study shows (Gołas 2017) -- Pre-exhaustion (PE) may not be as en vogue as it was 10-15 years ago, but Golas et al. are right to point out that it is still frequently applied in resistance training (RT).

    The idea is that pre-exhausting a supporting muscle group by manipulating the order of performing two resistance exercises, a single-joint exercise to momentary exhaustion, followed by a multi-joint movement that includes the same muscle group, will ensure greater recruitment of muscles or muscle groups in the multi-joint exercise to further increase muscle strength and overcome strength plateaus.
    Figure 1: The procedures flow chart in sessions 2, 3, and 4. RM = repetition maximum; BP = bench press; PE = pre-exhaustion; MVIC = maximal voluntary contraction (Golas 2017).
    One of the most popular of these single- plus multi-joint combinations consists of a combination of dumbells flies + flat bench presses. This was yet not the only exercise combination that was investigated by scientists from the Jerzy Kukuczka Academy of Physical Education (Golas 2017), recently. In eight healthy male athletes from various sports disciplines (at least 3 years of resistance training experience), the authors analyzed the effects of doing
    • incline dumbbell fly, 
    • front deltoid raise, and 
    • lying triceps extension exercise
    before flat bench presses on muscle activity by the means of electromyography. In four training sessions, the scientists determined the muscle activity of the pectoralis major (PM), anterior deltoid (AD), and triceps brachii (TB) during high-intensity (95% of 1 repetition maximum [RM]) bench press (BP): Session 1 was aimed at determination of 1RM during a flat BP. Sessions 2, 3, and 4 consisted of performing a BP after PE.
    Figure 2: Peak muscle activity for the pectoralis major (PM), anterior deltoid (AD), and triceps brachii (TB) muscles for the bench press exercise with and without PE with the load of 95% 1RM (Golas 2017).
    The results (see Figure 2) were kind of disappointing, though: While the peak concentric TB activation after TB PE (mean +/- SD, 147.76 +/- 18.6%) was significantly greater, the statistical analysis for PM and AD did not show any significant differences.

    Accordingly, the authors warn coaches not to expect pre-exhaustion protocols to elicit higher PM or AD activity or fatigue, but encourage them to use it whenever increasing the triceps brachii activity during high intensity exercise is the goal - like in the latter part of "chest + triceps"-day, a combination of which the study at hand cleary suggests that it makes sense. 
  • Dumbbells are your best choice for bench presses if maximal pec activity is your goal, but there's more... (Farias 2017) -- Yes, Farias latest paper is not the first study to investigate the differential effects using barbells (BB), dumbbells (DB) and the smith machine (SM) on bench press muscle activity. It is however, the first one I can remember that investigated the muscle activation, total repetitions, and training volume for 3 BP exercise modes (Smith machine, barbell, and dumbbell) that were followed by triceps extensions (TE) performed on a pulley system in N=19 healthy, resistance training, male subjects (1–3 hours of recreational resistance training with a training frequency of 3–6 days per week) - All subjects performed 3 testing protocols in random order, which included: 
    • smith machine bench presses + triceps extensions (P1),
    • barbell bench presses + triceps extensions (P2), and 
    • dumbbell bench presses + triceps extensions (P3) 
    All bench press exercises were performed for 4 sets with a 10-repetition maximum (RM) load and immediately followed by triceps extensions at the cable pulleys that were likewise performed for 4 sets with a 10RM load. A 2-minute rest interval was adopted between sets and exercises.
    Figure 3: EMG activity of pectoralis (green), anterior deltoids (blue), triceps brachii (orange) during bench press exercise using the smith machine (full), barbell (medium) and dumbbells (light color | Farias 2017).
    The data in Figure 3 represents the recorded surface electromyographic activity of the pectoralis major (PM), anterior deltoid (AD), biceps brachii (BB), and triceps brachii (TB).

    The results indicate that significantly higher total repetitions were achieved for the DBP (31.2 +/- 3.2) vs. the BBP (27.8 +/- 4.8). For the TE, significantly greater volume was achieved when this exercise was performed after the BBP (1,204.4 +/- 249.4 kg) and DBP (1,216.8 6 287.5 kg) vs. the SMBP (1,097.5 +/- 193 kg) - a result that clearly suggests that the smith machine fails to isolate the pecs as it allows you to cheat the bar up using the triceps, which will then be exhausted on the subsequent isolation exercise.
    Figure 4: Interpretation of the EMG results wrt to exercise selection according to training goals.
    Speaking of isolation: while it may not be news, it's still worth mentioning that the study at hand confirms that doing bench presses with dumbbells will elicit a significantly greater pectoralis muscle activity compared to using barbells. The smith machine, on the other hand, is very good at recruiting every muscle, but the pec. Since you can basically push into whatever direction you want (as long as part of the force propels the bar upwards),  it is not surprising that the smith machine bench press elicited significantly greater activity of the anterior deltoids than the barbell or dumbbell bench press.

    Interestingly enough, though, it was neither the dumbbell press with its ability to isolate the pecs, nor the smith machine press which overloads the anterior deltoids and the triceps, but rather the classic barbell bench press that yielded the highest triceps activity during the subsequent cable pulley triceps extensions.
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What do the results mean - practically speaking: The results of the first study are pretty self-explanatory. In contrast to what you will still read on the Internet, pre-exhaustion with flies and front delt raises, respectively, is not a valuable strategy to increase the load on the pectoralis and/or front deltoid during bench presses.

Doing lying triceps extensions before bench presses, on the other hand, will sign. increase the activation of the triceps. Interestingly enough, the same goes for doing barbell (yet not dumbbell or smith machine) bench presses before cable-pulley triceps extensions - the reasons for the last-mentioned observation are not clear and, in view of the fact that isolating the triceps is much less of a problem than isolating the pecs, probably also irrelevant.

That's much in contrast to the choice of the right gym equipment. A choice of which the second study in today's installment of "On Short Notice" suggests that it may well, if not should, include dumbbells (DBs), because DBs are clearly the #1 for pectoralis major activity on the bench - a bonus of which I have to remind you, however, that it is the result of a relatively reduced front delt and triceps activity. Your overall upper-body muscular development may thus still benefit most from the classic barbell bench press | Comment!
References:
  • Farias, DdA, Willardson, JM, Paz, GA, Bezerra, EdS, and Miranda, H. Maximal strength performance and muscle activation for the bench press and triceps extension exercises adopting dumbbell, barbell and machine modalities over multiple sets. J Strength Cond Res 31(7): 1879–1887, 2017
  • Gołas, A, Maszczyk, A, Pietraszewski, P, Stastny, P, Tufano, JJ, and Zaja˛c, A. Effects of pre-exhaustion on the patterns of muscular activity in the flat bench press. J Strength Cond Res 31 (7): 1919–1924, 2017