The isolated effect of balance training on muscle strength of the flexors and extensors of the knee, without accompanying strength training, has not been addressed in the past. Effects of a balance training program alone were compared to a strength training program. Balance and strength training were performed by 15 persons each for 6 weeks including 12 training units of 25 min. Balance training was performed on instability training devices such as rolling board, mini trampoline and large rubber ball. The 15 persons of the strength training group trained on machines for leg curls and on leg presses for 25 min per unit. Measurements for balance were performed with one-leg balance on a narrow edge and a tilting stabilometer for 30 s; maximum isometric strength was measured using an isokinetic device for each leg separately. The muscular balance between dominant and non-dominant leg was calculated. Strength gain was similar for the flexors and extensors in both groups. One-leg balance improved after balance training (P< 0.01) with a 100% increase over the strength training group (P < 0.05) and the stabilometer test for each person in the balance (P < 0.01), but not in the strength training group. In the balance group the initial difference between right and left diminished. The results indicate balance training to be effective for gain in muscular strength, and secondly, in contrast to strength training, equalisation of muscular imbalances may be achieved after balance training.

Overtraining may be one frequent cause of stagnation or decrease in performance capacity of athletes. Israel (19) differentiates between addisonoid (parasympathetic) and basedowoid (sympathetic) overtraining, characterized by inhibition or excitation. We tried to induce an overtraining syndrome in 8 experienced middle- and long-distance runners, based on an increase in training volume from an average 85.9 km (week 1) to 115.1 km (week 2) and 143.1 km (week 3) to 174.6 km per week (week 4). The influence of this training on cardiovascular, metabolic and hormonal parameters was examined with special respect to plasma and urinary catecholamines. Laboratory testing including graded treadmill running was performed on the days 0, 14 and 28. Training was held six days each week, with nearly 30 km per day in the fourth week. A stagnation in endurance performance capacity (running velocity at the aerobic-anaerobic transition range) and a decrease in maximum working capacity were observed in 6 and a stagnation in 2 of the 8 sportsmen, indicated by a decrease in total running distance from 4719 + 912 m to 4361 + 788 m during incremental treadmill ergometry. The sportsmen could neither improve nor could they even approximately reach their personal records during the subsequent competitive season. Subjective complaints, classified on a four-point scale, increased from 1.2 (week 1) to 3.2 in week 4. Glucose, lactate, ammonia, glycerol, free fatty acids, albumin, LDL, VLDL cholesterol, hemoglobin level (transient), leukocytes, and heart rate (before and during exercise) decreased significantly. Urea, creatinine, uric acid, GOT, GPT, gamma-GT, serum electrolytes (except phosphate and calcium) remained constant at the measuring times, CPK was elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Heat shock proteins (HSP) represent cell-protective and antioxidant systems that may be induced by reactive oxygen species, cytokines, and hyperthermia. In the present study, we evaluated the influence of heavy endurance exercise and training on HSP27 and HSP70 in peripheral leukocytes of 12 athletes (before and at 0, 3, and 24 h after a half-marathon) and 12 untrained controls on protein and mRNA levels by flow cytometry and RT/PCR, respectively. HSP transcripts increased significantly immediately after acute exertion accompanied by elevated levels of corresponding proteins. HSP protein expression remained high until 24 h postexercise. Significant increases of plasma interleukin-8, myeloperoxidase, and creatine kinase occurred after exercise. Basal HSP expression was usually lower in trained compared with untrained subjects. Applying in vitro heat shock to resting blood samples of all subjects significantly stimulated HSP mRNA, showing higher increases in trained individuals. The exercise-induced alterations indicate that immunocompetent cells became activated. In addition to heat stress, other exercise-associated stress agents (oxidants, cytokines) may have also participated in stimulation of HSP expression in leukocytes. The expression pattern of HSP due to training status may be attributed to adaptive mechanisms.

The effects of an 8-week unilateral contract-relax (CR) stretching training program (passive stretch after isometric contraction) on muscular performance were investigated in a group of 16 athletes. The flexibility, maximum torque and angular position as well as contraction work in movements of the knee joint were determined before training and after 4 and 8 weeks of training. The torque measurements were performed under isokinetic conditions, eccentrically at angular velocities of 60 degrees x s(-1) and 120 degrees x s(-1), isometrically at five different joint positions, and concentrically at angular velocities of 60, 120, 180 and 240 degrees x s(-1) using an isokinetic dynamometer. A surface electromyogram (EMG) of the thigh muscles (quadriceps and hamstrings) was recorded simultaneously. As compared to untrained control limbs, significant improvements in active and passive flexibility (up to 6.3 degrees in range of motion), maximum torque (up to 21.6%) and work (up to 12.9%) were observed, and these were especially pronounced under eccentric load conditions. A comparison between integrated EMG recordings during eccentric and concentric loads, as well as the interpretation of the training-induced changes in the EMG, suggest that muscular activity under eccentric loads may be impaired by mental processes.

Strenuous exercise increased HSP expression in blood immediately after the run, indicating a protective function of HSP in leukocytes of athletes to maintain function after heavy exercise. The downregulation of HSP-positive cells in trained athletes at rest seems to be a result of adaptation mechanisms to regular endurance training.