High-intensity strength training using weight machines and free-weights improves cholesterol levels as much as aerobic exercise in previously sedentary young women, researchers report in the British Journal of Sports Medicine.

The same strength training exercise program also reduced body fat, they add.Dr. Bharathi Prabhakaran and colleagues from the Old Dominion University, Darden College of Education, Norfolk, Virginia, assigned 12 healthy young women to a high-intensity, progressive strength training program and 12 others to a non-exercising 'control' group. Women in the exercise group performed a variety of resistance training exercises, including repeated leg curls, leg extensions, presses, press-up and biceps curls. Each training session lasted 45 to 50 minutes and women exercised 3 days a week for 14 weeks.

The control group did not participate in any structured exercise program.

'At the end of training... total cholesterol was significantly lower... in the resistance exercise training group than in the control group,' the investigators report. Resistance training reduced levels of low-density lipoprotein (LDL) cholesterol, the so-called 'bad' cholesterol -- by 14%, and did not affect levels of high-density lipoprotein (HDL) or 'good' cholesterol.

Body fat also decreased slightly in the group who engaged in resistance training, while measures of muscle strength improved.

In contrast, there were no such changes in the group of women who had not exercised, the investigators note. Studies link lower levels of both total and 'bad' cholesterol, as well as higher levels of 'good' cholesterol to a lower risk of heart disease. (by I.S.S.A.)  [TOP]
 

Training Decreases Muscle Glycogen Turnover During Exercise

The present study was undertaken to determine the effects of endurance training on glycogen kinetics during exercise. A new model describing glycogen kinetics was applied to quantitate the rates of synthesis and degradation of glycogen. Trained and untrained rats were infused with a 25% glucose solution with 6-H-3-glucose and U-C-14-lactate at 1.5 and 0.5 mu Ci . Min(-1) (where 1 Ci = 3.7 x 10(10) Bq), respectively, during rest (30 min) and exercise (60 min). Blood samples were taken at IO- min intervals starting just prior to isotopic infusion, until the cessation of exercise. Tissues harvested after the cessation of exercise were muscle (soleus, deep, and superficial vastus lateralis, gastrocnemius), liver, and heart. Tissue glycogen was quantitated and analyzed for incorporation of H-3 and C-14 via liquid scintillation counting. There were no net decreases in muscle glycogen concentration from trained rats, whereas muscle glycogen concentration decreased to as much as 64% (P < 0.05) in soleus in muscles from untrained rats after exercise. Liver glycogen decreased in both trained (30%) and untrained (40%) rats. Glycogen specific activity increased in all tissues after exercise indicating isotope incorporation and, thus, glycogen synthesis during exercise. There were no differences in muscle glycogen synthesis rates between trained and untrained rats after exercise. However, training decreased muscle glycogen degradation rates in total muscle (i.e., the sum of the degradation rates of all of the muscles sampled) tenfold(P < 0.05). This study has applied a model to describe glycogen kinetics in relation to glucose and lactate metabolism during exercise in trained and untrained rats. Training significantly decreases muscle glycogen degradation rates during exercise.(by European Journal)  [TOP]
 

Sideline tests for concussion may miss many cases of mild brain injury in high school and college athletes, with possible long-term effects on their mental functioning, according to researchers.

``The bottom line is that we need to better manage these cases,'' said Michael Collins, a neuropsychologist at Henry Ford Health System in Detroit. While many athletic trainers spot and appropriately manage head injuries on the field, according to Collins, some schools, particularly in rural areas, may rely only on the judgment of coaches who are unaware of the more subtle signs of concussion.

``Many people believe concussion means the loss of consciousness,'' he said. ``So when athletes aren't knocked out, they're put back in the game.''

Collins led a study of nearly 400 football players from four universities that looked at the risk factors for poor recovery from a mild brain injury. His team's findings, along with those from two other studies of head injuries in amateur athletes, appear in Wednesday's issue of the Journal of the American Medical Association. (by Medical Tribute) [TOP]