PTJ Sep Oct 2010.pdf

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fi tness frontlines G. Gregory Haff, PhD, CSCS, FNSCA about the AUTHOR G. Gregory Haff is an assistant professor in the Division of Exercise Physiology at the Medical School at West Virginia University in Morgantown, WV. He is a Fellow of the National Strength and Conditioning Association. Dr. Haff received the National Strength and Conditioning Association’s Young Investigator Award in 2001. High-Intensity Exercise Preserves Muscle Mass When Undertaken In Conjunction with a Carbohydrate- Reduced, Energy-Restricted Diet Obesity has become a major problem worldwide and is considered to be a major predictor of morbidity. Additionally, an increase in visceral fat depositions has been linked to insulin resistance and type 2 diabetes. Diets which provide high glycemic loads that are coupled with sedentary lifestyles have been linked to impaired glucose homeostasis and fat oxidation. One proposed method for reducing glycemic loads is to employ a diet low in carbohydrates. This practice has been shown to reduce fasting insulin and glucose levels, while increasing insulin sensitivity, which is typically suppressed in obese individuals with type 2 diabetes. From an exercise perspective, the use of high-intensity interval exercise has been shown to decrease muscle glycogen stores, while increasing oxidative capacity and improving insulin sensitivity. There are however, very few studies which examine both carbohydrate-restricted diets and high-intensity interval exercise. To address this, a recent study performed by Sartor and colleagues examined the effects of 14 days of carbohydrate-restricted diets coupled with high-intensity interval training. Nineteen subjects participated in this investigation with 10 subjects being placed in a carbohydrate-restricted diet coupled with high-intensity interval training and nine subjects only undertaking a carbohydrate-restricted diet. The carbohydrate-restricted diet required subjects to consume ~147 – 163g of carbohydrates per day, effectively reducing their carbohydrate intake from 54% of their total calories at baseline testing to 35% during the two-week intervention. Additionally, their caloric intake was decreased by ~500kcals over the course of the two-week study. The diet and exercise group performed up to 10 four-minute bouts of cycle exercise at 90% of VOpeak (maximal aerobic power) separated by 2 – 3 minutes 2 of rest. Prior to the two-week intervention, subjects participated in VO2peak assessment to determine their maximal aerobic power and oral glucose tolerance test, a resting glucose and insulin test, a measurement of resting energy expenditure, and a determination of their resting muscle glycogen levels. After the two-week intervention the same tests were repeated. Both groups demonstrated significant increases in oral glucose insulin sensitivity, reductions in their fasting expiratory exchange ratio, improvements in lipid profiles, and a reduction in leptin levels. Only the combination of high-intensity interval training and carbohydrate restriction resulted in significant increases in maximal aerobic power and maintenance of lean body mass. Based upon these findings, the authors concluded that energy-restricted diets and/or carbohydrate-restriction results in a reduction of risk factors for obese type 2 diabetic individuals over a relatively short period of time. Additionally, the inclusion of high-intensity exercise interventions with carbohydrate and caloric restriction helped to improve aerobic power and preserve lean body mass. While this study offers promising and interesting results, the author points out that a longer research intervention is necessary to elucidate the health benefits of combining high-intensity interval training with carbohydrate and caloric restriction. Sartor, F, De Morree HM, Matschke, V, Marcora, SM, Milousis, A, Thom, JM, and Kubis, HP. High-intensity exercise and carbohydrate-reduced energy-restricted diet in obese individuals. Eur J Appl Physiol (ahead of print). How Do the Muscles of Well-Trained Runners Respond to High-Intensity Interval Training Traditionally, endurance runners are thought to have an abundance of fiber area occupied by type I muscle fibers and some fast type IIa fibers comprising a small amount of fiber area. However, recent research has reported a much higher type IIa muscle fiber area as well as a higher lactate dehydrogenase (LDH) activity in these types of athletes than previously thought. Since LDH plays a role in lactate control and as lactate has recently been shown to be related to metabolic responses to exercise, these findings are particularly interesting. From a training perspective, high-intensity interval training plays a large role in the development of endurance athletes, as this type of training has been shown to result in significant improvements in performance as well nsca’s performance training journal • www.nsca-lift.org • volume 9 issue 5 4
fi tness frontlines as stimulate specific changes to maximal oxygen consumption. While the effects of high-intensity interval exercise have been widely investigated, very little research has been completed looking at its effects on intramuscular metabolic or fiber type adaptations. To address this issue, Kohn and colleagues recently examined the effects of six weeks of high-intensity interval training on muscular adaptations of 10 highly trained endurance athletes. Prior to the training portion of the study, each subject underwent a maximal aerobic power or VO2max test. During this test, the peak treadmill speed that the subject could run at for 30 seconds was determined and subjects then ran at this speed until exhaustion in order to determine their Tmax or time at maximum. Additionally, a submaximal treadmill test was used which corresponded to 64%, 72%, and 80% of peak treadmill speed. During this test lactate levels were assessed. Muscle biopsies were also taken before the initiation of the study in order to examine muscle morphology, myosin heavy chain content, single fiber identification, and an analysis of enzymatic activity. Specifically, isocitrate dehydrogenase, 3-hydroxyacetyl CoA dehydrogenase, and LDH activity were measured. The interval training intervention required subjects to run six intervals at 94% of their maximal treadmill speed for 60% of their Tmax time with a half of their 60% Tmax as their recovery between efforts. This training was undertaken for six weeks. After six weeks of training the subjects peak treadmill speed increased and their lactate production during at 64% and 84% peak treadmill speed decreased markedly. There was a slight nonstatistically significant decrease in type II muscle fiber size and no changes to maximal aerobic power, muscle fiber type, capillary supply, citrate synthase activity, and 3-hydroxyacetyl CoA dehydrogenase activity. LDH activity was increased significantly and was correlated to interval training speed, suggesting that those who ran at higher speeds had a greater increase in LDH activity. Overall, this novel data suggests that in highly trained runners, the primary adaptation to high-intensity interval training is related to improvements in lactate metabolism and not elevations in oxidative enzyme activities. Further research is needed in order to further understand the effects of this type of training in elite endurance athletes. Kohn, TA, Essen-Gustavsson, B, and Myburgh, KH. Specifi c muscle adaptations in type II fi bers after high-intensity interval training of welltrained runners. Scand J Med Sci Sports (ahead of print). Aquatic Resistance Training ImprovesMobility and Lower Limb Function after a Knee Replacement When individuals have knee replacement surgery there is a reduction in their ability to perform power and strength-based tasks with their lower body. Specifically, reductions in the ability to walk, ascend or descend stairs, and engage in other activities of daily living can occur. Impairments in these abilities appear to be related to reductions in knee extensor and flexor strength that can persist long after the surgery has been completed. Recently, aquatic exercise has been suggested as a training modality for people with knee or hip osteoarthritis. Individuals who have had knee replacement surgery may benefit from an aquatic exercise program. Recently, Valtonen and colleagues examined the effects of 12 weeks of aquatic resistance training on mobility, muscle power and muscle cross sectional area in a group of 50 older adults who had had knee replacement surgery. Subjects in the study had to be 4 – 18 months removed from knee replacement surgery and be between the ages of 55 – 74 years of age. Two intervention groups were formed, with one group performing no exercise and the other engaging in the aquatic resistance training program. Prior to and after the completion of the intervention the subjects were assessed for walking speed, stair climbing ability, and self reported functional difficulty, pain, and stiffness. Leg extension and flexor strength was assessed with the use of an isokinetic dynamometer, while the leg muscle cross sectional area was measured with the use of computed tomography. After the 12-week study, the aquatic resistance training group demonstrated a 9% increase in walking speed and a 15% reduction in stair climbing time. These positive performance changes occurred in conjunction with a 32% increase in leg extensor power for the leg which contained the knee replacement and 10% increase in the leg which was not operated on. Additionally, the operated leg demonstrated a 48% increase in flexor power, while the non-operated leg increased by 8%. Finally, the cross sectional area of the surgically repaired leg was increased by 3% and the non-operated leg increased by 2% when compared to controls. Overall, the study suggests that aquatic resistance training offers a positive stimulus for adaptations that translates into functional performance in individuals who have recently undergone knee replacement surgery. Valtonen, A, Poyhonen, T,Sipila, S, and Heinonen, A. Effects of aquatic resistance training on mobility limitation and lower-limb impairments after knee replacement. Arch Phys Med Rehabil 91:833 – 839. 2010. nsca’s performance training journal • www.nsca-lift.org • volume 9 issue 5 5
Page 1 and 2: NSCA’s Issue 9.5 Sept./Oct. 10 ww
Page 3: table of CONTENTS 8 4 7 17 core tra
Page 7 and 8: in the gym Kyle Brown, CSCS about t
Page 9 and 10: Core Training Figure 1. Loading sta
Page 11 and 12: Core Training 6a. 6b. 6c. 6d. Figur
Page 13 and 14: feature about the AUTHOR David J. S
Page 15 and 16: Core Training Table 2. General Trun
Page 17 and 18: training table about the AUTHOR Deb
Page 19 and 20: ounce of prevention Jason Brumitt,
Page 21 and 22: ounce of prevention Develop Power a
Page 23: NSCA COACHES CONFERENCE DALLAS, TEX
Page 26: “With Keiser equipment we are abl

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