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Research Bites

Bracko, Michael R. Ed.D., FACSM

doi: 10.1249/FIT.0b013e318279470d
COLUMNS: Research Bites

Pilates is great for the abs; Going to failure in strength training — necessary or not?; More good news about high-intensity interval training.

Michael R. Bracko, Ed.D., FACSM, is an exercise physiologist and director of Dr. Bracko’s Fitness in Calgary, Canada. He is a fitness educator, presenter, media consultant, and writer. He works in sports physiology for performance enhancement for hockey players. He is the strengh and conditioning coach for the U.S.A. Men’s Deaflympic Hockey Team. He also works in occupational physiology in the areas of back injury prevention, ergonomics, work-station stretching, and pre-work warm-up.

Disclosure: The author declares no conflict of interest and does not have any financial disclosures.

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This study investigated the effect of a Pilates training program (Modern Pilates) on the volume of the rectus abdominus and oblique/transverse abdominus conjointly (OT). The volume of these muscles was measured with magnetic resonance imaging on nine women (median age, 36 years).

The Pilates workout consisted of a 36-week, twice weekly, 55 minute per session program. The workouts were done with four or less students who always trained together. The workouts were at the same time of day and taught by the same certified Pilates instructor.

After the 36-week Pilates training, the volume of the dominant OT increased by 8%, and the nondominant OT remained unchanged. Interestingly, before Pilates, the volume of the nondominant OT was 8% greater than the dominant OT, indicating that Pilates training can compensate for muscle imbalances. The total volume of the dominant rectus abdominus increased by 21%, and the nondominant rectus abdominus increased by 20%. There were no side-to-side asymmetries in the rectus abdominus observed before or after Pilates training.

The researchers suggest that 36 weeks (9 months) of Pilates is good for improving hypertrophy of the abdominal wall muscles, especially in the rectus abdominus. Pilates also can eliminate preexisting muscle imbalances. Good news for Pilates lovers all over the world (1)!



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The researchers suggest that going to failure has been one of the most debated issues in the history of strength training. As such, they set out to evaluate muscle activation with electromyography (EMG) during heavy resistance-low repetitions versus low resistance-high repetitions.

Fifteen untrained women (median age, 42 years) performed a set with heavy resistance (3 repetition maximum [RM]) and a set of repetitions to failure with light resistance (15 RM) during a lateral shoulder raise with rubber resistance. The EMG and median power frequency were used to evaluate the splenius capitis, upper trapezius, medial deltoid, and infraspinatus from the dominant side.

The results indicate that during the failure set, EMG was significantly lower during the first repetition and significantly higher during the latter repetitions compared with the heavy 3-RM set. EMG of the muscles increased throughout the set to failure in a curvilinear manner (i.e., trapezius 86% to 124% of maximal voluntary contraction) and reached a plateau during the last three to five repetitions before failure. There was a high level of muscle activity during the movement, and a plateau was reached at 10 to 12 repetitions during the low resistance-high repetition set. During the heavy resistance-low repetition set, high EMG levels (>60% of maximum voluntary contraction EMG) were observed in the evaluated muscles.

Based on the results, the researchers indicate that full activation of the muscles can be reached in three to five repetitions before failure, indicating that training to failure is not necessary to recruit the muscles effectively (2).

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The research investigated the aerobic and anaerobic benefits of high-intensity interval training (HIIT) performed at a work-to-rest ratio of 1:2 (90-second work bouts with 180-second rest). This protocol was used because the authors indicate that little data exist on this work-to-rest ratio.



Active male subjects (median age, 21 years) were assigned to an HIIT group (N = 10) or a control group (N = 11) randomly. Maximal oxygen uptake (V˙O2max) was measured in each subject on a cycle ergometer, and each one also completed a 30-second Wingate test. Lactate was acquired from blood samples taken from the antecubital vein.

The HIIT training protocol consisted of the following: cycle power output of 80% of V˙O2max applied for six 90-second work bouts followed by a 180-second passive rest. The control group was enrolled in a physical education teaching methods class that was not designed to improve fitness.

The results indicate that the HIIT group improved on the following variables: V˙O2max (5.5 mL/kg per minute), anaerobic threshold (3.8 mL/kg per minute), work output (12.5 J/kg), glycolytic work (11.5 J/kg), mean power (0.3 W/kg), peak power (0.4 W/kg), and max power (0.4 W/kg). After testing, mean blood lactate was lower for the HIIT group at the 5-minute mark and significantly so at the 15-minute mark.

The researchers conclude that, for athletes and people wanting to improve fitness, using an HIIT work-to-rest ratio of 1:2 can produce improved maximal aerobic and anaerobic cycling performance in a relatively short training time (3).

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1. Dorado C, Calbert JAL, Lopez-Gordillo A, Alayon S, Sanchis-Moysi J. Marked effects of pilates on the abdominal muscles: A longitudinal magnetic resonance imaging study. Med Sci Sports Exerc. 2012; 44 (8): 1589–94.
2. Sundstrup E, Jakobsen MD, Andersen CH, Zebis MK, Mortensen OS, Andersen LL. Muscle activation strategies during strength training with heavy loading vs. repetitions to failure. J Strength Cond Res. 2012; 26 (7): 1897–903.
3. Ziemann E, Grzywacz T, Luszczyk M, Laskowshi R, Olek RA, Gibson AL. Aerobic and anaerobic changes with high-intensity interval training in active college-aged men. J Strength Cond Res. 2011; 25 (4): 1104–12.
© 2013 American College of Sports Medicine.