Dr. Squat - Dr. Fred Hatfield

Not much has come in here in the last few days, so I'll add some stuff and will look for more later

EXRX article on HIIT - a brief discussion and the basic protocol

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Impact of exercise intensity on body fatness and skeletal muscle metabolism
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Impact of Exercise Intensity on Body Fatness and Skeletal Muscle Metabolism - A highly condensed and brief article using the below as reference.

From medline:
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Title: Impact of exercise intensity on body fatness and skeletal muscle metabolism.
Author: Tremblay A
Add.Author / Editor: Simoneau JA

Bouchard C
Citation: Metabolism: Clinical & Experimental 43(7):814-8, 1994 Jul
43(7):814-8, 1994 Jul
Year: 1994
Abstract: The impact of two different modes of training on body fatness and skeletal muscle metabolism was investigated in young adults who were subjected to either a 20-week endurance-training (ET) program (eight men and nine women) or a 15-week high-intensity intermittent-training (HIIT) program (five men and five women). The mean estimated total energy cost of the ET program was 120.4 MJ, whereas the corresponding value for the HIIT program was 57.9 MJ. Despite its lower energy cost, the HIIT program induced a more pronounced reduction in subcutaneous adiposity compared with the ET program. When corrected for the energy cost of training, the decrease in the sum of six subcutaneous skinfolds induced by the HIIT program was ninefold greater than by the ET program. Muscle biopsies obtained in the vastus lateralis before and after training showed that both training programs increased similarly the level of the citric acid cycle enzymatic marker. On the other hand, the activity of muscle glycolytic enzymes was increased by the HIIT program, whereas a decrease was observed following the ET program. The enhancing effect of training on muscle 3-hydroxyacyl coenzyme A dehydrogenase (HADH) enzyme activity, a marker of the activity of beta-oxidation, was significantly greater after the HIIT program. In conclusion, these results reinforce the notion that for a given level of energy expenditure, vigorous exercise favors negative energy and lipid balance to a greater extent than exercise of low to moderate intensity. Moreover, the metabolic adaptations taking place in the skeletal muscle in response to the HIIT program appear to favor the process of lipid oxidation.
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Short-term sprint interval versus traditional endurance training: Similar initial adaptations in human skeletal muscle and exercise performance
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Another interesting article on the effects of SIT vs ET on muscle oxidative capacity and glycogen content over a 14day cycle in ~21year olds, this time from EMBASE: Excerpta Medica
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Resource: EMBASE: Excerpta Medica
Title: Short-term sprint interval versus traditional endurance training: Similar initial adaptations in human skeletal muscle and exercise performance
Author: Gibala MJ
Add.Author / Editor: Little JP
van Essen M
Wilkin GP
Burgomaster KA
Safdar A
Raha S
Tarnopolsky MA
Citation: Journal of Physiology. Vol. 575(3)(pp 901-911) , 2006.
Year: 2006
Abstract: Brief, intense exercise training may induce metabolic and performance adaptations comparable to traditional endurance training. However, no study has directly compared these diverse training strategies in a standardized manner. We therefore examined changes in exercise capacity and molecular and cellular adaptations in skeletal muscle after low volume sprint-interval training (SIT) and high volume endurance training (ET). Sixteen active men (21 +/- 1 years, V o2peak = 4.0 +/- 0.21 min -1 ) were assigned to a SIT or ET group (n = 8 each) and performed six training sessions over 14 days. Each session consisted of either four to six repeats of 30 s 'all out' cycling at ~250% with 4 min recovery (SIT) or 90-120 min continuous cycling at ~65% (ET). Training time commitment over 2 weeks was ~2.5 h for SIT and ~10.5 h for ET, and total training volume was ~90% lower for SIT versus ET (~630 versus ~6500 kJ). Training decreased the time required to complete 50 and 750 kJ cycling time trials, with no difference between groups (main effects, P <= 0.05). Biopsy samples obtained before and after training revealed similar increases in muscle oxidative capacity, as reflected by the maximal activity of cytochrome c oxidase (COX) and COX subunits II and IV protein content (main effects, P <= 0.05), but COX II and IV mRNAs were unchanged. Training-induced increases in muscle buffering capacity and glycogen content were also similar between groups (main effects, P <= 0.05)"[/u]