Health-Promoting Effects of Serial vs. Integrated Combined Strength and Aerobic Training.

Combined strength and aerobic training programs are widely used for improving markers of physical fitness and health. We compared the efficiency of a serial and an integrated combined training program on health and overall fitness in middle-aged females. 54 females (46.7±4.5yrs) were assigned to a serial (SCG) or an integrated (ICG) combined training group or to a control group (CG). The SCG and ICG performed a 3-month training combining aerobic dance and calisthenics. The 2 training programs differ in the sequence of aerobic and strength exercises. SCG performed the strength exercises prior to aerobic; in ICG, the aerobic and strength exercises were altered in a predetermined order. Body composition/circumferences, blood pressure, respiratory function, flexibility, balance, muscle strength/endurance, power and aerobic capacity were measured before and after training. SCG and ICG significantly increased muscle strength and endurance, power, aerobic capacity, flexibility, balance, fat-free mass and respiratory function (p<0.001-0.05), while significant reductions were observed for blood pressure, heart rate and body fat/circumferences (p<0.001-0.05). However, there were no significant differences between SCG and ICG after training. Serial and integrated combined training programs confer analogous adaptations and can be used interchangeably for counteracting the detrimental effects of sedentary lifestyle on indices of physical fitness and health.

Reliability of concentric and eccentric strength of hip abductor and adductor muscles in young soccer players.

The concentric and eccentric strength profile and muscular balance of the hip joint are important parameters for success in soccer. This study evaluated the reliability for the assessment of hip abduction and adduction isokinetic strength over a range of angular velocities (30 and 90°/s) and types of muscular actions (concentric and eccentric) in young soccer players. The reliability for the assessment of reciprocal (conventional and functional) and bilateral torque ratios was also examined. Fifteen male soccer players (15±1 years) performed two sessions, separated by three days. The testing protocol consisted of five maximal concentric and eccentric hip abductions and adductions of both legs at angular velocities of 30°/s and 90°/s. The peak torque was evaluated in young soccer players using an isokinetic dynamometer (Cybex Norm), and the reciprocal strength ratios (conventional and functional) and bilateral ratios (non-preferred to preferred leg ratios) were calculated. The test-retest reliability for the assessment of peak torque (ICC = 0.71-0.92) and of reciprocal muscle group ratios (ICC = 0.44-0.87) was found to be moderate to high. Bilateral torque ratios exhibited low to moderate reliability (ICC = 0.11-0.64). In conclusion, isokinetic strength of hip abductor and adductor muscles and the conventional and functional strength ratios can be reliably assessed in young soccer players, especially at low angular velocities. The assessment, however, of bilateral strength ratios for hip abductor/adductor muscles should be interpreted with more caution.

Can maximal handgrip strength and endurance be improved by an 8-week specialized strength training program in older women? A randomized controlled study.

Maximal handgrip strength and endurance are important indicators of upper limb function in older adults. Up to now, there is insufficient information regarding the efficacy of specialized strength training programs for improving handgrip strength. The purpose of this study was to investigate the effectiveness of an 8-week specialized handgrip strength training program on maximal handgrip strength and endurance in healthy older women. A randomized controlled trial was performed. Thirty-six healthy older women (>65 years) were randomly divided into a training group (TG) (n = 18) and a control group (CG) (n = 18). The TG participated in an 8-week specialized handgrip strength training program using rubber balls and hand grippers (2 training sessions/week, 10-15 min, 8-15 repetitions/set, 4-6 total sets/session). Prior to and after the completion of the program, maximal handgrip strength and dynamic endurance (indices: repeated maximal repetitions and percentage change in handgrip strength between first and last 6 repetitions) were assessed in both hands. Repeated measures MANOVA results indicated that maximal handgrip strength (+9.3%-10.4%) and strength values during repeated maximal repetitions (+14% to 27%) significantly increased in TG (p < 0.001), while the percentage change in handgrip strength between the first and last 6 repetitions decreased significantly (-6%) (p < 0.05), irrespective of the tested hand. The results of this study showed that an 8-week specialized handgrip strength training program can be used effectively by athletic trainers, physical and hand therapists to counteract the detrimental effects of the aging process on maximal handgrip strength and endurance in older adults.

Does the number of trials affect the reliability of handgrip strength measurement in individuals with intellectual disabilities?

The main objectives of this study were to examine which testing protocol (one/two/three trials) and method (best/average value) used for determining maximal handgrip strength is more reliable for individuals with intellectual disabilities (ID) and to compare the reliability and variability of maximal handgrip strength measurement between individuals with ID and healthy individuals. Twenty individuals with ID (18.7±3.3 years) and 20 healthy individuals (18.5±3.4 years) performed six separate sessions. During these sessions, the participants' maximal handgrip strength was evaluated using three protocols with different number of trials (one/two/three). In individuals with ID, the protocols with one and two trials were less reliable (ICC=0.78-0.95; SEM%=9-21) than the protocol with three trials (ICC=0.94-0.96; SEM%=8-10) whereas in healthy individuals all protocols were equally reliable (ICC=0.95-0.99; SEM%=1.9-4.9). In individuals with ID, the mean of three trials (ICC=0.96, SEM=1.19-1.35kg, SEM%=8.2-8.7) had slightly higher reliability than the best of three trials (ICC=0.94, SEM=1.47-1.75kg, SEM%=9.2-10.1). Furthermore, the variability of maximal handgrip strength measurement was about twofold higher in individuals with ID (CV=37-45%) vs. healthy individuals (CV=21-23%). Maximal handgrip strength can be measured reliably in young individuals with ID using the mean of three trials as the most reliable approach for the determination of maximal handgrip strength.

Prediction of knee extensor and flexor isokinetic strength in young male soccer players.

STUDY DESIGN: Single group, cross-sectional study. OBJECTIVES: To measure various anthropometric and demographic variables in young male soccer players and to use these measurements to develop equations with which to predict the isokinetic, concentric, and eccentric moment of force. BACKGROUND: The development of equations that can predict isokinetic muscle strength from commonly measured subject characteristics can assist in the effective design of training and rehabilitation programs for athletic children. METHODS AND MEASURES: One hundred thirteen male soccer players (13.50 +/- 2.21 years of age) performed eccentric and concentric maximum efforts of the knee extensors and flexors at 60, 120, and 180 degrees/second. Stepwise regression tests were used to develop predictive equations using combinations of age, height, body mass, sexual maturation (Tanner) stage, percentage of body fat, and hours spent training per week. RESULTS: The results indicated a significant relationship of concentric and eccentric isokinetic strength for both knee extensors and flexors with 73-93% of the variance explained by using combinations of age, body mass, percentage of body fat, and hours training per week. Body mass and age were the main predictor variables under concentric conditions, whereas chronological age was not included in the models under eccentric conditions. CONCLUSIONS: The relation between isokinetic moment and multiple anthropometric and demographic variables depends on the type of muscle action examined. The results suggest that the equations we developed can be used to predict the isokinetic moment in trained, young soccer players. A cross-validation analysis is required to confirm the accuracy and the suitability of the equations developed in our study.

Combined effects of age and maturation on maximum isometric leg press strength in young basketball players.

AIM: Muscular strength of the leg extensor muscles in children can be affected by several factors such as age, sexual maturation, body mass and training status of the subjects. The purpose of the study was to examine maximal isometric strength characteristics of young male basketball players taking into consideration the combined effects of chronological age and sexual maturation. METHODS: One hundred and twenty male basketball players, aged from 12 to 17 years divided into 6 equivalent age subgroups performed maximum bilateral isometric leg press efforts. The parameters analysed were the maximal voluntary isometric force (MVC), relative strength (MVC/body mass and MVC/fat free mass), starting strength (F50: force exerted during the first 50 ms of the contraction) and speed strength index (the ratio of maximal force to time to attain maximal force). RESULTS: The results indicated that in almost all absolute force parameters, the 12-and 13-year olds demonstrated significantly (p<0.05) lower values compared with the 15(-1)6-and 17-years old groups. Age differences were also significant (p<0.05) when the effects of sexual maturation were taken into consideration in the statistical analysis but they were reduced when strength was adjusted for body mass. Finally, no significant differences for strength per unit of fat free mass were found (p>0.05). CONCLUSIONS: Maximum absolute strength of basketball players is significantly increased from 12 to 17 years and as sexual maturation stage increases. It also appears that body mass and fat free mass should be taken into consideration when examining age effects on strength in basketball players.

Isokinetic peak torque and hamstring/quadriceps ratios in young basketball players. Effects of age, velocity, and contraction mode.

AIM: The purpose of this study was to provide an extensive isokinetic profile, including peak torque and "functional" and "conventional" muscle group ratios, of basketball players throughout the developmental years 12-17. Furthermore, we investigated the effects of age and angular velocity on peak torque and reciprocal muscle group ratios, and observed the force-velocity pattern. METHODS: Basketball players (n=180) 12 to 17 years. were divided according to their age in 6 equal (n=30) groups aged 12, 13, 14, 15, 16, 17 years. All subjects performed maximum knee extension and flexion efforts at 60 inverted exclamation mark /s and 180 inverted exclamation mark /s angular velocities under eccentric and concentric conditions. The absolute (Nm) peak torque was measured, and the relative peak torque (PT/BW) and "functional" and "conventional" reciprocal muscle group ratio (%) were calculated. RESULTS: PT/BW values of knee flexors ranged from 0.98 to 2.29 Nm/kg and of extensors from 1.53 to 3.69 Nm/kg, across all age, velocity, and muscle action levels. PT/BW was higher at slow speed and during eccentric contraction irrespective of age and angular velocity/muscle action. The results indicated a significant (p<0.05) age-related increase in peak torque independent of changes in BW. The force-velocity patterns were similar across ages. The "functional" and "conventional" ratios were not affected by age, but increased with increase in angular velocity, except the CON(KF)/ECC(KE) ratio that was higher (p<0.05) at slow speed. CONCLUSION: The present study provides an extensive isokinetic profile of a knee joint in basketball players throughout developmental years 12-17. Coaches and physical therapist may use these information when evaluating and planning exercise programs during training and rehabilitation.