While it is well accepted that higher intensity sets require longer rest periods than lower intensity ones to stave off this performance decrease, no one has been able to determine exactly what causes the fatigue. One of the more popular theories on the decreased performance associated with fatigue centers around the accumulation of lactic acid due to anaerobic work like that seen in strength training. Researchers at University Blaise Pascal in France recently conducted an experiment in an attempt to determine if lactic acid was the main culprit, and to shed some light on optimum rest intervals.
The researchers divided 10 male subjects into 3 groups. Each group performed 10 sets of 6 reps in the bench press at 70% of their 1RM. The groups were assigned different rest intervals with group 1 getting 1 minute's rest, group 2 getting 3 minutes rest and group 3 getting 5 minutes rest. Subjects were measured for blood lactate, mean power during each rep (MPR) and mean power during each set (MRS). No differences were observed between the 3 minute and the 5 minute group in either blood lactate levels, MRP or MRS. The 1 minute group, however, did show higher blood lactate levels than the other two groups and a lower MPS from sets 4-10 than the other groups. Interestingly enough, although the MRS was lower, only reps 4, 5 and 6 showed a lowered MPR.
Enter the amount of weight you lifted (Lbs/Kg) and the number of reps you completed. Your One Rep Max (1 RM) will appear at the bottom left, and your various percentages of 1 RM will appear on the right side.
Researchers concluded that although muscular power and blood lactate levels were effected by the recovery interval, the acidosis associated with lactic acid was not the main cause of fatigue. They theorized that the insufficient rest periods did not allow for optimal regeneration of creatine phosphate stores and that in turn effected performance. This suggests that to maintain power from set to set, a few minutes' rest is warranted to restore these phosphagen levels.
Effects Of Cross-Training On Characteristics Of Type II Diabetes
Exercise is known to have numerous positive physiological effects on the human body, particularly on markers of insulin resistance and hyperinsulinemia (chronically high levels of insulin), both of which are characteristic of type II diabetes. While most diabetic training programs have centered on endurance-based exercise, researchers at the United States Sports Academy looked to see if adding resistance training to these programs would increase their effectiveness.
The study randomly assigned the participants to two groups. One group performed 30 minutes of aerobic exercise at 60-70% of heart rate reserve 3 times a week for 14 weeks while the second group added resistance training to their program. Both the endurance group and the cross-training group demonstrated similar increases in VO2Max. However, only the cross-training group demonstrated increases in 1RM in the bench press and the leg press.
In addition, the changes seen in the cross-training group were greater than the endurance-only group in percent of bodyfat, insulin concentration, glucose levels, HDL cholesterol levels, triglyceride concentration and systolic blood pressure. These results strongly suggest that those who suffer from insulin resistance and hyperinsulinemia should incorporate a strength-training program into their exercise routine, to see the best results possible.
Muscle Fiber Adaptation To Creatine Supplementation
Many of us know that creatine increases performance and bodyweight in most users, yet the actual means by which those increases happen is still a mystery to most. Researchers for the Center for Sports Medicine at Penn State University recently looked at the physiological effects that creatine supplementation has on muscle fibers, in an attempt to shed some light on the subject.
Nineteen resistance-trained men were assigned in a double-blind placebo manner to either a creatine group or a placebo group. Both groups loaded their "supplement" at 25 grams a day for the first 5 days, and then cut back to a maintenance dose of 5 grams for the remainder of the 12-week study period. The creatine group exhibited greater increases in body mass, fat-free mass and 1RM in the bench press and squat than the placebo group. Researchers also found significantly increased cross-sectional area in Type I, Type IIA and Type IIB muscle fibers, along with increased muscle creatine concentrations.
In addition, it was determined that the average volume lifted during bench press training was much greater for the creatine group. Researchers concluded that creatine supplementation enhanced fat-free mass, physical performance and muscle morphology. It was theorized that these changes were in response to the resistance training, particularly the higher quality training sessions tolerated through creatine supplementation. On a side note, no adverse effects were reported at any time by any of the subjects.
Rep Tests To Determine 1RM On The Bench Press
We've all seen the charts that claim to predict a 1RM based on how many reps you can do with a certain weight. If you base training weight on a percentage of 1RM then you no doubt have used them from time to time as a substitute for conducting an actual 1RM test on yourself or your clients. But how accurate are these tests? Researchers at Northeast Missouri State compared 6 common equations used in estimating 1RM based on a rep test.
Subjects ranged from untrained college students to resistance-trained football players, and were all tested in the same manner. Each was tested for true 1RM in the bench press, and a few days later chose a weight and then performed as many repetitions as possible with it. Researchers found that there was a wide range of discrepancies displayed by all of the equations in predicting a subject's true 1RM. This led the team to suggest caution when using these equations to predict 1RM, although they did say that using the average of two equations could cut down on the error.