(10) ACUTE EFFECTS OF ESCALATING DENSITY TRAINING ON CARDIORESPIRATORY AND PERCEPTUAL RESPONSES

Background: Superset training, defined as performing two or more exercises in succession with an abbreviated or no rest interval, has become an increasingly popular method of time-efficient training for coaches, athletes, and trainers. A form of superset training, escalating density training (EDT), is a time-efficient style of resistance training that increases sets and repetitions within a given timeframe (i.e., training density) for a given session. This type of training substantially decreases the amount of time spent at rest, allowing for a greater training density compared to traditional resistance training (TRAD).  To date, no evidence investigating the acute or chronic physiological response of EDT exists.

Purpose: To compare the acute physiological, perceptual, and enjoyment responses between a single bout of EDT and TRAD.

Methods: On separate days, twelve physically active males (n = 6) and females (n = 6) (age: 21.4 ± 3.0 yrs; weight: 69.8 ± 7.9 kg; height: 172.9 ± 12.4 cm; peak oxygen consumption [VO₂peak]: 44.7 ± 9.2 ml · kg^-1 · min^-1) performed both EDT and TRAD. During the EDT trial, participants performed chest and leg press exercises in a superset fashion for 15 minutes. Subjects were encouraged to perform as many sets as possible during the 15-minute period and to self-select rest intervals. For the TRAD trial, the same exercises were performed for sets of up to 8 repetitions until volume was matched from the EDT trial. For both conditions, repetitions were performed at a load corresponding to 10-repetition maximum with a 2:1 second cadence. Oxygen consumption (VO₂) and heart rate (HR) were measured before and during exercise. Blood lactate (BLa) was measured pre- and post-exercise. Creatine kinase (CK) was measured pre- and 48 hours post-exercise. Rating of perceived exertion (RPE), physical activity enjoyment (PACES), and VO₂ were measured post-exercise for the estimation of energy expenditure.

Results: There were no differences between average pre-exercise oxygen consumption for EDT (4.7 ± 1.0 ml · kg · min^-1) and TRAD (4.9 ± 1.3 ml · kg · min^-1) conditions (p = 0.086).  Oxygen consumption relative to VO₂peak was higher (p < 0.001) during EDT (56.2 ± 6.8%) compared to TRAD (23.7 ± 4.7%). Heart rate relative to HRpeak was higher (p = 0.021) for EDT (78.9 ± 7.9%) compared to TRAD (53.0 ± 15.8%). Estimated total exercise energy expenditure was greater (p < 0.001) during EDT (55.9 ± 15.3 kJ · min^-1) compared to TRAD (29.4 ± 13.4 kJ · min^-1). There were no differences (p = 0.051) between average pre-exercise BLa between EDT (1.0 ± 0.2 mmol/L) and TRAD (0.8 ± 0.2 mmol/L). Compared to TRAD, BLa was higher (p < 0.05) 5- and 10-min post-exercise for EDT. No differences were observed between average pre-exercise CK (p = 0.934). Creatine kinase 48-hrs post exercise was significantly greater (p < 0.05) following EDT compared to TRAD. Average RPE achieved was higher (p < 0.001) during EDT (8.8 ± 0.8) compared to TRAD (5.5 ± 1.9), but PACES was similar for EDT and TRAD (p = 0.176).

Conclusions: When training volume is matched, EDT presents a time-efficient alternative to TRAD during which cardiorespiratory stress, energy expenditure, metabolic stress, and markers of exercise-induced muscle damage are higher. PRACTICAL APPLICATOIN: EDT may serve as an effective method of RT for experienced exercisers, trainers, and coaches seeking to decrease training time while simultaneously increasing training density.

Acknowledgements: UNM GPSA NMRG