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Voluntary & NMES contractions for Monster Quads?

You are always looking for new ways to improve your training outcome? Scientists from the Department of Physiotherapy at the University Cardenal Herrera-CEU might have something for you, then. In their latest study, V. Benavent-Caballer, P. Rosado-Calatayud, E. Segura-Ortí, J.J. Amer-Cuenca, and J.F. Lisón tried to elucidate, whether conducting low intensity resistance training in conjunction with  neuromuscular electrical stimulation (NMES) would provide not just an additional growth stimulus, but also corresponding increases in physical performance, muscle cross-sectional area (CSA) and the capacity to perform daily tasks 22 in exactly those subjects researchers will resort to, when they're looking for generous funding for studies the outcome of which is not going to pay off in form of scripts for a new patentable drug: Older adults living in a geriatric nursing home.
What? Yeah... I have to admit, the subjects are not exactly bodybuilders and a regular high intensity control is missing, but even if it wasn't for the necessary fact that you'll belong to the group of "older adults" in 50 years from now, the results of the study at hand would still have a certain relevance for younger trainees. Why? Well, something that makes the elderly grow will certainly do the same in young people. Whether it does so at the same or even higher rates than "regular" strength training will obviously have to be elucidated in future studies.

Table 1: Subject characteristics;  VC = volitional contraction; NMES = neuromuscular electrical stimulation; NMES+ = NMES superimposed onto voluntary contraction. SD = standard deviation (Benavent-Caballer. 2014)

For now, all I can tell you is that the three weekly supervised 30-35 min exercise sessions the 89 participants of the study at hand performed in the course of this 16-week study lead to significantly more pronounced strength and size gains, when the exercise was performed using both voluntary contractions and the forced contractions, the researchers produced by attaching their subjects to the surface electrodes of a portable NMES devices (TensMed S82).
The four adhesive surface electrodes (5 × 5 cm) were placed on the distal medial and proximal lateral portions of the subject's anterior thigh, when they performed their three sets of knee extensions (15 reps each) in a single-leg fashion with 3-minute rest between sets.

Figure 2: Changes in muscle strength (hand grup) and size (rectus femoris), as well as changes in parameters of physical functioning in response to the three training modalities (Benavent-Caballer. 2014)

The participants were instructed to raise the weight in 1 s (concentric phase), keep a full knee extension for 3 s (isometric phase) and slowly lower the weight in 2 s to the starting position (eccentric phase). Each contraction was followed by a 2-second rest period, and the training intensity was set at 40% of 1RM... and yeas, this sounds pretty much like peak contractions, an intensity technique which may in fact be the reason that the old trainees in the study at hand recorded highly significant increases in muscle size even when the peak contraction or rather the whole movement was not superimposed with NMES which was delivered with a ramp-up time of 1 s increasing intensity as the knee was extended from 90° to full extension that was followed by 3 s keeping the knee in full extension and 2 s of a ramp-down with gradually decreasing intensity (see Figure 2, yellow).
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