Below is a partial list of the research studies that helped us develop our protocols. Since our competition has already attempted to copy our methods and original bibliography, this list includes only about 20% of the studies on our current list which is growing each day as new research comes out. Our full list including key studies is available to those who wish to form partnerships or business opportunities and sign a comprehensive non-disclosure agreement.
The select list below however, is comprehensive to the extent that it includes studies supporting all our protocols, methods, and X Gym theories on topics of strength training, flexibility, nutrition, fitness testing and cardiovascular exercise. The italics describe the topic of study, and the rest includes the reference and title.
*2021 edit with additions section*
We are always studying the research and updating/upgrading our methodology, so the following section is our most recent research discoveries.
Note that CMF stands for Complete Muscle Fatigue and TUT stands for Time Under Tension, which are two of our proprietary and Xclusive X Gym principles behind our vastly superior results compared to other trainers and gyms.
CMF produces cardio fitness: “Resistance Training to Momentary Muscular Failure Improves Cardiovascular Fitness in Humans: A Review of Acute Physiological Responses and Chronic Physiological Adaptations,” E Space, last modified December 15, 2019, http://e-space.mmu.ac.uk/263356/.
CMF is the key - not the weight load or rep number: Cameron J. Mitchell et al., “Resistance Exercise Load Does Not Determine Training-Mediated Hypertrophic Gains in Young Men,” Journal of Applied Physiology 113, no. 1 (July 2012): 71–77, https://doi.org/10.1152/japplphysiol.00307.2012.
Heavy weights not necessary if CMF is achieved: Michiya Tanimoto et al., “Effects of Whole-Body Low-Intensity Resistance Training With Slow Movement and Tonic Force Generation on Muscular Size and Strength in Young Men,” Journal of Strength and Conditioning Research 22, no. 6 (November 2008): 1926–1938, https://doi.org/10.1519/jsc.0b013e318185f2b0.
Low weight, high reps (aka TUT) stimulate muscle growth as well as high weight, low reps“The Effect of Strength Training Volume on Satellite Cells, Myogenic Regulatory Factors, and Growth Factors,” Scandinavian Journal of Medicine & Science in Sports 23, no. 6 (March 2012): 728–739, https://doi.org/10.1111/j.1600-0838.2012.01452.x.
AND (same topic)
Brad J. Schoenfeld et al., “Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men,” Journal of Strength and Conditioning Research 29, no. 10 (October 2015): 2954–2963, https://doi.org/10.1519/jsc.0000000000000958.
AND (same topic)
“Why Lift Heavy Weights When You Don’t Have to?” The Globe and Mail, June 14, 2015, https://www.theglobeandmail.com/life/health-and-fitness/why-lift-heavy-weights-when-you-dont-have-to/article24943287/; Robert W. Morton et al., “Neither Load nor Systemic Hormones Determine Resistance Training-Mediated Hypertrophy or Strength Gains in Resistance-Trained Young Men,” Journal of Applied Physiology 121, no. 1 (July 2016): 129–138, https://doi.org/10.1152/japplphysiol.00154.2016.
Heavy weights and controlled speed training give similar results: Brad J. Schoenfeld et al., Differential Effects of Heavy Versus Moderate Loads on Measures of Strength and Hypertrophy in Resistance-Trained Men,” Journal of Sports Science and Medicine 15, no. 4 (December 2016): 715–722, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5131226/;
AND (same topic)
W. L. Westcott et al., Effects of Regular and Slow Speed Resistance Training on Muscle Strength,” The Journal of Sports Medicine and Physical Fitness 41, no. 2 (June 2001): 154–158, https://www.ncbi.nlm.nih.gov/pubmed/11447355.
High reps (AKA TUT) build muscle as well as low reps: Brad Schoenfeld et al., “Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men,” Journal of Strength and Conditioning Research 29, no. 10 (October 2015): 2954–2963, https://doi.org/10.1519/JSC.0000000000000958;
AND (same topic)
Bent R. Rønnestad et al., “Dissimilar Effects Of One- And Three-Set Strength Training On Strength And Muscle Mass Gains In Upper And Lower Body In Untrained Subjects,” Journal of Strength and Conditioning Research 21, no. 1 (February 2007): 157–163, https://doi.org/10.1519/00124278-200702000-00028; Hanssen et al., “The Effect of Strength Training,” 728–739, https://doi.org/10.1111/j.1600-0838.2012.01452.x.
No difference between single and multi-set for strength gains: Hass, C.J. et al. Single vs. multi sets in long term recreational wt. lifters. Med. Sci. Sport and Exer. 31:235-242. 1999.
4 reps to failure compared to 10 reps to failure elicit similar results: Jour. of Str. & Cond. Res. (13):353-359-1999.
Minor changes in a program helps prevent plateaus: Neuromuscular adaptation to power and endurance work. Can. J. Appl. Sport Sci. 1:49-58. 1976.
Varying methods promote equal muscle and tendon tissue adaptations and strength improvements: Effect of physical training on collagen. Ital. J. Biochem. 24:64-65. 1975;
Effect of eight weeks’ physical training on muscle and connective tissue:… J. Geron. 32 (1):33-37. 1977.
High power output (tieredos, mid stops) during the lifting phase of ea. rep incr. testosterone output, while hi reps w/moderate power output (70% max) leads to incr. growth hormone. High volume (many sets and reps over a long workout) decreases testosterone but incr. growth hormone. Hi rep set (Jennies) incr. testosterone: Bossco C, et al. (2000). Monitoring strength training: neuromuscular and hormonal profile. Med. & Sci. in Sports and Exer. 32:202-208.
Innervation must happen first, hypertrophy next: Komi, P.V. Training of muscle strength and power: Interactions of neuromotoric, hypertrophic, and mechanical factors. Int. J. Sports Med. 7:10-15. 1986.
Intense workouts best for strength improvement: Sale, D.G. Neural adaptations to resistance training. Med. Sci Sports Exer. (1988) 29Lsuppl): 135-145.
Training to failure produces more strength and the more training you do in a workout (volume), the less intensity you’ll generate: Canadian Exercise Physiologists presentation at the annual meeting of the Canadian Society of Exercise Physiology, held in Quebec, Nov. 2001. [Ironman, June 2002]
Shrier, I. (1999) Stretching before exercise does not reduce the risk of local muscle injury: a critical review of the clinical and basic scientific literature. Clinical Journal of Sports medicine. 9: 221-227.
Kokkonen, J., et al. (1998) Acute muscle stretching inhibits maximal strength performance. Research quarterly for Exercise and Sport. 69:411-415.
Beedle, B., et al. (1991) Flexibility characteristics among athletes who weight train. J Applied Sports Science Research. 5:150-154.
Thrash, K, et al. (1987). Flexibility and strength training. J Applied Sports Science Research. 1:74-75.
Campell WW, Barton, ML, Cyr-Campell D, et al. Effects of an omnivorous diet compared with a lacto-vegetarian diet on resistance training-induced changes in body composition and skeletal muscle in older men. American Journal of Clinical Nutrition 1999; 70:1032-1039.
Flynn, M.G., et al. (1990). Fat storage in athletes: metabolic and hormonal responses to swimming and running. Int J Sports Med. 11:433-440.
Gwinup, G. (1987). Weight loss w/o dietary restriction: efficacy of different forms of aerobic exercise. Amer J Sports Med. 15:275-279.
Sheldahl, L.M,. et al. (1982). Effects of exercise in cool water on bodyweight loss. Int J Obesity. 6:29-42.
Brenner, B.M., et al. (1982). Dietary protein intake and the progressive nature of kidney disease: the role of hemodynamically mediated glomular injury in the pathogenesis of progressive glomlular sclerosis in aging, renal ablation and intrinsic renal disease. New Eng J Med. 307: 652-659.
Balanced dieters 31% less likely to die and 20% lower risk of stroke, cancer and heart disease than those on “shunning” diets like Atkins, etc. J of Amer Med assoc. Apr. 26, 2000. Natl cancer institute/City Univ. of NY.
3 hr. Post-workout protein window: Journal of Applied Physiology (2):386-392, 2000 AND Univ. of Texas study cited in Nov. 2000 issue of Ironman Mag. AND The following studies found in Jan 2002 Ironman Pg. 52: Macdougal, J., et al. (1995) The time course for elevated muscle protein synthesis following heavy resistance exercise. Can J Appl Physiol. 29(4):480-486. AND Biolo, G., et al. (1995). Increased rates of muscle protein turnover and amino acid transport after resistance exercise in humans. Am J Physiol. 268(3):E514-520. AND pg. 133, same issue: Flakoll, L.J. (2000). Ingestion of a post-exercise nutrient supplement containing protein carbohydrate and fat produces a dose-responsive increase in whole-body protein accretion. Faseb J. 14:A229. AND Biolo G; Tipton KD; Klein S; Wolfe RR Department of Metabolism, Shriners Burns Institute, Galveston, Texas, USA. Am J Physiol, 273(1 Pt 1):E122-9 1997 Jul (http://www.ast-ss.com/research/breaking/b-r_10-6-99.asp)
Cottage cheese is great fat burning and muscle building aid. Annals of Nutrition and Metabolism, Jan. 2000.
Don’t train after hard cardio: Journal of Str. & Cond. (13):47-51,1999
Satellite cells may alter gene expression from weight training: Exer. % Sport Science Reviews 28(1):24-36, 2000.
Warm up before lifting is valuable: Safran, M.R., W.E. Garrett, A.v. Seaber, R.R. The role of warm up in muscular injury prevention. Amer. Jour. of Sp. Med. 16:123-129, 1988. [Fitness Management, Apr. 2000].
Stretch for 30 sec. not 15 or 60: Bandy, WD, JM Irion and M Briggler. The effect of time and frequency on static stretching on flexibility of the hamstring muscles. Physical Therapy. 77 (10): 1090-1096, 1997. [Fitness Management, Apr. 2000].
Stretching before a workout is not a sufficient warm-up or even very good for flexibility improvement. Stretching after works great: I Shrier and K. Gossal. Myths and Truths About Stretching. Phys. & Sportsmed. 28.8 (2000). [Muscle Media, Dec. 2000].
High protein seems to minimize the metabolic decline of fat restriction. Whitehead, J.M., McNeill, G. & Smith, J.S. (1996) The effect of protein intake on 24-hour energy expenditure during energy restriction. Itl. Journ. Of Obesity & Related Metabol. Disorders, 20, 727-732. [Oct. 2000, Muscle Mag]
Amt. of force applied: Regulation of bone mass by mechanical strain magnitude. Calcif. Tissue Int. 37:411-417. 1985.
Rate of speed on bone mass: The influence of strain rate on adaptive bone remodeling. J. Biomech. 15(10):767-781. 1982
Intense Exercise Best for Bones: Vincent KR, Braith RW. Resistance exercise and bone turnover in elderly men and women. Medicine and Science in Sports and Exercise 2002:34(1), pp. 17-23.
Direction of force on bone mass: Regulation of bone formation by applied dynamic loads. J. Bone Joint Surg. 66(3):397-402. 1984.
Faster recovery w/better aerobic fitness: Human Bioenergetics and its applications. Exercise Physiology. New York: Wiley. 1984
Weight training improves cardio: Health and performance related adaptations to resistive training. Sports Med. 11(4):210-231. 1991.
Cardio helps weight training recovery: Plisk, S.S. Anaerobic metabolic conditioning: A brief review of theory, strategy and practical application. J. Appl. Sport Sci. Research. 5(1):22-34. 1991.
Too much cardio can slow strength gains: Interference of strength devel. by simul. training for strength & endur. Eur. J Appl. Physiol. 45:255-263.1980.
Training 3 days a week is best for conventional training: Berger, R. (1972, August). Strength & Health, pp. 44-45, 70-71.
Longer recovery (>48 hrs.) is needed for higher intensity and eccentric loading: Weiss. L., Journal of Applied Sport Science Research. 5 (4): 219-227, 1991.
Pauletto, B. Rest and Recuperation Validity. NSCA Journal 8 (3):52-53. 1986.
Weighted crunch best for rectus abdominus activation: Cornacchia, L; Bompa, T. Ph.D: 2000, November issue of Ironman p. 28.Weighted crunch: 77% activation, Nautilus: 69%, Pulle: 68%.
2 cardio sessions split up by a break in between or strength session and then a cardio after a break is best for fat burning: Stich, V. et al. (2000) Adipose tissue lipolysis is increased during a repeated bout of aerobic exercise. J App Phys. 88:1277-1283.
Don’t sit down between sets! Stay active while recovering for best subsequent set performance. Corder, K.P. Potteiger, J.A., Mau, K.L., et. al. Effects of active and passive recovery conditions on blood lactate, rating of perceived exertion and performance during resistance exercise. Journal of Strength and Cond. Res. 14(2):1510156, 2000.
Exercisers get 25% more improvement from a trainer than alone in 12 weeks. Med & Sci. in Sp. & Exer. (6):1,175,2000.
High protein OK for normal kidneys: Poortmans, J.R., et. al. (2000). Do regular high protein diets have potential health risks on kidney function in athletes? Int. J. Sport Nut. Ex. Metab. 10:28-38.
Even small muscle group exers can trigger growth factor release: Eliakam, A., et. al. (2000). Effect of single wrist exer on fribroblast growth factor 2, insulin-like growth factor and growth hormone. Amer. J. Physiology. 279: R548-R553.
Muscle can be built at any age: Akima, H., et al. (2001). Muscle Function in 164 men and women aged 20-84 yrs. Medicine and Sci. in Sport and Exer. 33:220-226. [Ironman Mag. Aug. 2001, p.30]. And HIT is best: Ohio Univ. Physiologists (http://www.ast-ss.com/research/breaking/sept00/b-r_9-28-00.asp)
Carbs cause insulin to spike and stay elevated up to 7 hours later: Taylor, R.; Price, T.B. et. al., (1993). Direct measurement of change in muscle glycogen concentration after a mixed meal in normal subjects. Am. J. Physiology 265:E224-E229.
Insulin shuts down fat-burning: Bonnadonna, R.C: Groop, L.C.: et. al., (1990). Dose-dependent effects of insulin on plasma free fatty acid turnover and oxidation in humans. Am. J. Physiology 259:E736-E750.
THR formulas work for only 50% of us: Dwyer, J. Metabolic character of exercise at traditional intensities in cardiac patients and healthy persons. J. of Cardiopulminary Rehab. 14:189-196, 1994.
Talk test validity: Dehart-Beverly, M., C.F. Foster, J.P Portcari, D.C.W. Fater and R.P.M. Mikat. Relationship between the talk test and ventilatory threshold. Clinical Exercise Physiology 2(1):34-38, 2000.
70% will drop out of traditional fitness programs w/in the first few months: 1.)Annesi, J.J. Effects of computer feedback on adherence to exercise. Perceptual and Motor Skills 87:723-730, 1998. 2.)Dishman, R.K. Exercise Adherence: It’s impact on public health. Human Kinetics: Champaign Ill., 1988.
There are now more ex-health club members than members: IHRSA The American Fitness Industry’s Plan For Growth, Boston Mass., 1999.
3 Factors governing member adherence: 1.) the amount of social support received (from spouse, friend, family, other exercisers) 2.) participant’s ability to use self-management and self control strategies (positive self-talk, goal setting, etc.) 3.) ability to tolerate physical discomfort. Annesi J.J.
The effect of perceived activity choice on exercise adherence: Thompson, C.E., et al., J. of applied Social Psychology 10:436-443, 1980.
Swimming is a poor method of weight loss: Svedenhag, J., J. Seger. Running on land and in water. Comparative exercise physiology. Med. Sci. Sports Exer. 24(20):1155-1160. 1992.
Active recovery day validity:
—Staron, R.S., et. al., Strength and skeletal muscle adaptations in resistance trained women after detraining and training. J. Appl. Physiol. 70:631-640. 1991.
—Bridges, C.R., B.J. et. al., Skeletal muscle bioenergetics during frequency-dependent fatigue. Amer. J. Physiol. 29:C643-C651. 1991.
—Craig, B.W., J. Lucas, et. al., The effect of running, weightlifting and a combination of both on growth hormone release. J. Appl. Sport Sci. Res. 5(4):198-203. 1991.
—Willoughby, D. The effects of mesocycle-length weight training programs involving periodization and partially equated volumes on upper and lower body strength. J. Strength and Cond. Res. 7(1):2-8. 1993.
—Weiss, L. The obtuse nature of muscular strength: The contribution of rest to its development and expression. J. Appl. Sports Sci. Res. 5(4):219-227. 1991.
— Corder, K.P. Potteiger, J.A., Mau, K.L., et. al. Effects of active and passive recovery conditions on blood lactate, rating of perceived exertion and performance during resistance exercise. Journal of Strength and Cond. Res. 14(2):1510156, 2000.
Strength helps endurance: The relationship Between Field tests of Anaerobic Power and 10-km Run Performance. Sinnett, Aaron, et al. J. of Str. & Cond. Res. Vol 15, #4, 405-412, 2001.
HIT cardio for better fat burning: AlMulla, N, et al. (2000) Post-exercise adipose tissue skeletal muscle lipid metabolism in humans: the effects of exercise intensity. J Physiol. 524:919-928. and J Appl. Phys. (http://www.ast-ss.com/research/breaking/b-r_7-14-00.asp)
No difference between young and old in muscle gains: Akima, H., et al. (2001). Muscle function in 164 men and women aged 20-84 years. Med. Sci. Sports Exer. 33:220-226.
Most excess carbs are burned off or stored as energy, not converted to fat: acheson K.J. et al. (1982). Glycogen synthesis vs. lipogenesis after a 500 g carb meal in man. Metabolism. 31:1234-1240. AND Flatt, J.P. et al. (1985). Effects of dietary fat on postprandial substrate oxidation and on carb/fat balances. J. Clin. Invest. 76:1019-1024.
Protein diets burn more fat when compared to carb diets of same calories: Mikkelson, P.B. et al. (2000). Effect of fat-reduced diets on 24 hour energy expenditure… Am J. Clin Nutr. 72:1135-41.AND Skov, A.R. et al. (1999). A randomized rtial of protein vs. carb in ad libitum fat-reduced diet for the treatment of obesity. Int. J. Obesity. 23:528-36.
Same calories divided into 6 meals instead of 3 promoted wt. loss, less chol., and better insulin resp.: Fabry, P., et al. “the frequency of meals: its relation to hypercholesterolemia and decr. Glucose tolerance”. Lancet, 1964; 2: 614-615.
Grazing helps reduce atherosclerosis: Jenkins, D. J. A.,Wolever, T.MS., Vuksan, V., et al. “Nibbling Versus Gorging: Metabolic Advantages of Increased Meal Frequency.” New England Journal Of Medicine, 1989: 321: 929?934.
Grazing lowers total chol. And raises ratio: McGrath, S.A. and Gibney, M.J. “The Effects of Altered Frequency of Eating on Plasma Lipids in Free-living Healthy Males on Normal Self-selected Diets,” European Journal Of Clinical Nutrition, June 1994 (6): 402-7
Grazing helps reduce appetite and makes overeating less likely: International Journal Of Obesity & Related Metabolic Disorders, 1999, 23 (11): 1151-9
Grazing helped boxers lose weight w/o losing as much lean mass as their dieting counterparts: Scandinavian Journal Of Medicine & Science In Sports 1998 6 (5):265-72.
People who graze are thinner, more active and energetic, smoked less, drank less alcohol and had lower chol: Titan, S.M.O., Bingham, S., Welch, A., Luben, R, etc al. “Frequency of Eating and Concentrations of Serum Cholesterol in the Norfolk Population of the European Prospective Investigation into Cancer: Cross Sectional Study. British Medical Journal December 1, 2001; 323:1286
Superslow results are superslower than they claim (10 week study): Keeler, L.K., et.al(2001) J. Str. Cond. Res. 15:309-14.
Superslow inferior for weight loss: Hunter, G.R., D. Seelhorst, and S. Snyder. Comparison of metabolic and heart rate responses to super slow vs. traditional resistance training. Human Studies Department, University of Alabama at Birmingham, Birmingham, Alabama 35294. Printed in The Journal of Strength and Conditioning Research: Vol. 17, No. 1, pp. 76–81.
Vegans can expect reduced testosterone output: University of Buffalo, J. of Nutr. Biochemistry. (http://www.ast-ss.com/research/breaking/b-r_2-23-99.asp)
200-400-100 UI of Vit E may help reduce DOMS: NEW ORLEANS, Apr 23 (Reuters Health) vitamin E might be of benefit to help combat soreness and exercise-induced stress,” said lead researcher Dr. Jennifer Sacheck, of Tufts University in Boston, Massachusetts. She presented the findings here Tuesday at the annual Experimental Biology 2002 conference. Sacheck’s team knew that vitamin E was a powerful antioxidant, capable of soaking up excess free radicals produced as a bi-product of exercise.
Glutamine helps build muscle and burn fat; and reduce soreness and speed recovery when coupled with vit. E: 1. Keast, D., Arstein, D., et al. “Depression of plasma glutamine concentration after exercise stress and its possible influence on the immune system.” Med J Aust, 162: 15-8, 1995. 2. MacLennan, P.A., Smith, K., et al. “Inhibition of protein breakdown by glutamine in perfused rat skeletal muscle.” FEBS Lett, 257: 133-36, 1988. 3. Welbourne, T.C. “Increased plasma bicarbonate and growth hormone after an oral glutamine load.” Am J Clin Nutr, 61: 1058-61, 1995. 4. Welbourne, T.C., & Joshi, S. “Interorgan glutamine metabolism during acidosis.” Jnl Parent Ent Nutr, 14: 775-855, 1990. 5. Rudman, D., Kutner, M.H., et al. “Impaired growth hormone secretion in the adult population: Relation to age and adiposity.” J Clin Invest, 67: 1361-69, 1981. 6. Opara, E.C., Petro A., et al. “L-glutamine supplementation of a high fat diet reduces body weight and attenuates hyperglycemia and hyperinsulinemia in C57BL/6J mice.” J Nutr, 126: 273-79, ! 1996.
IMPACT OF EXERCISE INTENSITY ON BODY FATNESS AND SKELETAL MUSCLE METABOLISM
Tremblay et al (1) compared the effects of a 15-week high-intensity, intermittent training (HIIT) protocol and a 20-week endurance-training (ET) protocol on body fat and skeletal muscle enzyme activity. 8 men and 9 women participated in ET, while 5 men and 5 women participated in HIIT. Training was performed on a cycle ergometer. ET involved 30-45 minutes of continuous cycling at 60-85% max HR reserve 4-5 times a week. HIIT involved bouts of short-interval work and long-interval work; short-interval work consisted of 10-15 bouts of 15-30 seconds of cycling at 60% maximum 10-second power output. Long-interval work consisted of 4-5 bouts of 60-90 seconds of cycling at 70% maximum 90-second work output. Recovery between bouts was sufficient to allow HR to return to 120-130 bpm. Intensity was increased in both the short-interval and long-interval protocols by 5% every 3 weeks. Total energy cost of the training sessions was estimated by referring to VO2 max and maximal work-output measurements. Body fat was measured before and after the ET and HIIT protocols by the sum of 6 skinfolds. Enzyme activity of hexokinase (HK), phosphofructokinase (PFK), malate dehydrogenase (MDH), and 3-hydroxyacyl coenzyme A dehydrogenase (HADH) were measured before and after the training protocols using muscle biopsies. VO2 max was measured before and after training using a progressive cycle ergometer test to exhaustion, and maximal cycle work output for 10, 30, and 90 seconds were also measured.
FINDINGS: Mean estimated total energy cost of the ET program was 120.4 MJ, while that of the HIIT program was 57.9 MJ. Despite the lower energy cost of exercise, subjects engaged in HIIT tended to have greater reductions in skinfolds than the ET group. When expressed on a per MJ basis (change in skinfolds divided by energy cost of training program), the HIIT group’s reduction in body fat was 9 times higher than the ET group (p < .01).
Both protocols resulted in significant increases in MDH activity, while the HIIT program significantly increased HK activity while the ET program significantly reduced HK activity. The HIIT program also resulted in significant increases in PFK and HADH activity, while the ET program did not significantly change these measures.
Both programs resulted in a significant increase in VO2 max, and the HIIT program resulted in a significant increase in maximal cycle work output for 10, 30, and 90 seconds.
IMPLICATIONS: This study gives more evidence to support the idea that high-intensity interval training is a more optimal program for fat loss than moderate-intensity, continuous endurance exercise. The HIIT group in this study lost nine times more body fat than the ET group for each MJ of energy expended during training, indicating HIIT is much more efficient and effective. More evidence of the effectiveness of the HIIT program is evident in the significant greater increase in HADH activity as compared to the ET program; HADH is a marker of the activity of beta oxidation. Higher HADH activity means more body fat is being used as a fuel source during rest. This shows that the reason why HIIT is so effective in reducing body fat is the increase in fat metabolism during the rest periods between training sessions; basically, you lose more fat while sitting around on the couch.
The increase in VO2 max seen with both protocols indicates that both HIIT and ET can be an effective methods for increasing VO2 max. An increase in VO2 max means the body can consume more oxygen to produce energy and thus perform more work, increasing performance on the track, the road, or other athletic endeavor where oxygen uptake plays a major role in performance.
1. Tremblay, A., J. Simoneau, and C. Bouchard. Impact of Exercise Intensity on Body Fatness and Skeletal Muscle Metabolism. Metabolism. 43(7):814-818. 1994.
Protein requ. Up to 2.0 g/kg of bodyweight daily for athletes: Brouns, F. Nutritional needs of athletes: 37-47. New York: John Wiley & Sons, 1993. AND Tarnopolsky, et al. “Influence of protein intake and training status on nitrogen balance and lean mass”. J. of Appl. Physiol. 64: 187-193, 1988. AND Hi Gragan, G.L. Vasiliu, V. Et al. “Effect of increased supply of protein on elite weight lifters” in T.E. Galesloot & B.J. Tinebergen, eds. Milk Proteins: 99-103. Wageningen, The Netherlands: Pudoc, 1985. AND Marable, N.L. Hickson, J.F. et. al. “Urinary nitrogen excretion as influenced by a muscle-building exercise program and protein intake variation” Nutritional Reports Itl’ 19:795-805, 1979. AND Lemon, P.W.R. “Do athletes need more dietary protein and amino acids?” Int’ J. of Sp. Med. 5: S39-S61, 1995.
Up to 2.0 g/kg of bodyweight daily for protein intake isn’t hard on liver or kidneys: Durnin, J.V.G.A. “Protein requirements and physical activity” in V.A Parizkova, Pa.Llea & Febiger, 1988.
GH release higher w/HIT but time of day doesn’t affect it but training in evening does increase cortisol release. Eating high fat and high carb b4 training blunts GH release. Kanaley, J.A et al. (2001). Cortisol and growth hormone responses to exercise at different times of day. J Clin Endocrinol Metab. 86:2881-2889.
Seasoned athletes may need more recovery time. Busso, T. et al. (1994)._ Fatigue and fitness modeled from the effects of training on performance. Eur J Appl. Physiol. 69:50-54.