Interaction between resistance training and flexibility training in healthy young adults

To test the hypothesis that increases in muscle strength and flexibility are developed by specific training programs, 43 healthy young adults were tested before and after 4 different interventions conducted twice a week for 12 weeks: (a) resistance training only (n = 13); (b) flexibility training only (n = 11); (c) resistance and flexibility training (n = 9); and (d) no intervention (n = 10). There was no change in either strength or flexibility in the control group (p > 0.05). Resistance training improved muscle strength either alone (+14%; effect size = 0.53; p < 0.001) or in combination with flexibility training (+16%; effect size = 0.66; p = 0.032), but did not change flexibility (p = 0.610). Flexibility increased with specific training alone (+33%; p < 0.001) or in combination with resistance training (+18%; p < 0.001). In conclusion, in young, healthy subjects, resistance training alone did not increase flexibility, but resistance training did not interfere with the increase in joint range of motion during flexibility training. These results support the concept that specific training should be employed in order to increase either muscle strength or flexibility.     

Associations of maximal strength and muscular endurance test scores with cardiorespiratory fitness and body composition

The purpose of the present study was to assess the relationships between maximal strength and muscular endurance test scores additionally to previously widely studied measures of body composition and maximal aerobic capacity. 846 young men (25.5 ± 5.0 yrs) participated in the study. Maximal strength was measured using isometric bench press, leg extension and grip strength. Muscular endurance tests consisted of push-ups, sit-ups and repeated squats. An indirect graded cycle ergometer test was used to estimate maximal aerobic capacity (V(O2)max). Body composition was determined with bioelectrical impedance. Moreover, waist circumference (WC) and height were measured and body mass index (BMI) calculated. Maximal bench press was positively correlated with push-ups (r = 0.61, p < 0.001), grip strength (r = 0.34, p < 0.001) and sit-ups (r = 0.37, p < 0.001) while maximal leg extension force revealed only a weak positive correlation with repeated squats (r = 0.23, p < 0.001). However, moderate correlation between repeated squats and V(O2)max was found (r = 0.55, p < 0.001) In addition, BM and body fat correlated negatively with muscular endurance (r = -0.25 - -0.47, p < 0.001), while FFM and maximal isometric strength correlated positively (r = 0.36-0.44, p < 0.001). In conclusion, muscular endurance test scores were related to maximal aerobic capacity and body fat content, while fat free mass was associated with maximal strength test scores and thus is a major determinant for maximal strength. A contributive role of maximal strength to muscular endurance tests could be identified for the upper, but not the lower extremities. These findings suggest that push-up test is not only indicative of body fat content and maximal aerobic capacity but also maximal strength of upper body, whereas repeated squat test is mainly indicative of body fat content and maximal aerobic capacity, but not maximal strength of lower extremities.     

Impact of genetic counseling and DNA testing on individuals with colorectal cancer with a positive family history: a population-based study

What is the impact of a genetic evaluation for colorectal cancer susceptibility? We previously reported a study of individuals diagnosed with colorectal cancer at 60 years of age or less in a five-county area of New York including Rochester. Subjects reporting at least one first- or second-degree relative with colorectal cancer were invited to receive genetic counseling and DNA testing. Of the 37 persons tested, we previously reported that 6 were found to have deleterious mutations in MSH2 or MLH1. A mutation has since been found in a seventh subject in another laboratory. To evaluate the impact of the testing experience, we followed-up on 36 of these 37 subjects at 3 and 12 months after communicating their DNA test result. We ascertained their knowledge of colon cancer, whether they told relatives their test result, their surveillance behavior, and their mental health. Three months after receiving their result, subjects knew more about colon cancer if they had more cancer of all types in their family (p = 0.02). At 12 months, they knew more if they had been found to have a mutation (p < 0.001), were younger when DNA tested (p < 0.01), or were younger when diagnosed with cancer (p < 0.03). All but 1 of those found to have an abnormality told relatives. Relatives of 3 subjects in whom a mutation had been found came to us to be tested themselves. At 12 months, surveillance for colon and endometrial cancer was more adherent if there were more total cancers in the family (p < 0.05) or if the testee were more worried about cancer (p < 0.05). Self-assessed mental health at 12 months was better for those who were married (p < 0.05). This study suggests that individuals undergoing a genetic evaluation for an inherited susceptibility to colorectal cancer pursue recommended surveillance and inform relatives of their result.     

Predicting strength in high school women athletes

The purpose of this study was to investigate the hypothesis that a repetitions-to-maximum test is a predicator of a 1 repetition maximum (1RM) performance for evaluating upper and lower body strength in women high school athletes. Fifty-seven high school athletes ages 14-18 participated in this study. All of the participants completed a 1RM bench (1RMBP) and leg press (1RMLP) test, as well as leg press repetitions-to-fatigue (91 kg; LPRTF91) and bench press repetitions-to-fatigue (27 kg; BPRTF27) tests. A Pearson product correlation and regression analysis was used to determine relationships between 1RM strength and the repetitions-to-fatigue for upper and lower body strength. On the basis of the data analysis, it was concluded that BPRTF27 had a high correlation with 1RMBP strength (r = 0.802) and LPRTF91 had a correlation with 1RMLP strength (r = 0.793), indicating that these test measures were viable alternatives to 1RM testing for strength assessment. A regression analysis further confirmed that BPRTF27 was a significant variables in developing the model 1RMBP = 28.88 + (0.68)BPRTF27 for predicting upper body strength (p < 0.001). Similar results occurred 1RMLP = 106.3 + (2.4)LPRTF91 in developing the lower body model (p < 0.001). From data analysis, it was concluded that repetitions-to-fatigue testing can be used to evaluate upper and lower body strength in women high school athletes.     

Simulating distal radius fracture strength using biomechanical tests: a modeling study examining the influence of boundary conditions

Distal radius fracture strength has been quantified using in vitro biomechanical testing. These tests are frequently performed using one of two methods: (1) load is applied directly to the embedded isolated radius or (2) load is applied through the hand with the wrist joint intact. Fracture loads established using the isolated radius method are consistently 1.5 to 3 times greater than those for the intact wrist method. To address this discrepancy, a validated finite element modeling procedure was used to predict distal radius fracture strength for 22 female forearms under boundary conditions simulating the isolated radius and intact wrist method. Predicted fracture strength was highly correlated between methods (r = 0.94; p < 0.001); however, intact wrist simulations were characterized by significantly reduced cortical shell load carriage and increased stress and strain concentrations. These changes resulted in fracture strength values less than half those predicted for the isolated radius simulations (2274 ± 824 N for isolated radius, 1124 ± 375 N for intact wrist; p < 0.001). The isolated radius method underestimated the mechanical importance of the trabecular compartment compared to the more physiologically relevant intact wrist scenario. These differences should be borne in mind when interpreting the physiologic importance of mechanical testing and simulation results.     

Age and sex differentially affect regional changes in one repetition maximum strength

To assess the influences of age and sex on regional changes in 1 repetition maximum (1RM) strength, 10 young men (20-30 years), 8 young women (20-30 years), 11 older men (65- 75 years), and 10 older women (65-75 years) were studied before and after a 24-week whole-body strength training program. Changes in 1RM strength were analyzed for each individual exercise, as well as by calculating a total body score (TBS), an upper body score (UBS), and a lower body score (LBS). The effect of age and sex on changes in 1RM strength was analyzed using a repeated measures analysis of variance. When changes in strength for individual exercises were analyzed, the chest press, lat pulldown, shoulder press, and triceps pushdown were affected by both age (p < 0.05) and sex (p < 0.05), while the biceps curls were only influenced by age (p < 0.05). For the lower body, the leg press changes in 1RM strength were influenced by age (p < 0.0001), while leg extension was influenced by sex (p < 0.05). Total body score, UBS, and LBS showed significant increases with 24 weeks of ST (p < 0.001, all). Changes in TBS and UBS were affected by age (p < 0.001, both) and sex (p < 0.05 and p < 0.001, respectively). Younger subjects showed a greater increase in strength than older subjects, and men showed a greater increase in strength compared with women. Changes in LBS were affected by age (p < 0.001), with younger subjects showing a greater increase in strength compared with the older subjects, but not by sex (p = 0.464). These data indicate that regional increases in strength are differentially affected by age and sex.     

Quantitative analysis of single- vs. multiple-set programs in resistance training

The purpose of this study was to examine the existing research on single-set vs. multiple-set resistance training programs. Using the meta-analytic approach, we included studies that met the following criteria in our analysis: (a) at least 6 subjects per group; (b) subject groups consisting of single-set vs. multiple-set resistance training programs; (c) pretest and posttest strength measures; (d) training programs of 6 weeks or more; (e) apparently "healthy" individuals free from orthopedic limitations; and (f) published studies in English-language journals only. Sixteen studies generated 103 effect sizes (ESs) based on a total of 621 subjects, ranging in age from 15-71 years. Across all designs, intervention strategies, and categories, the pretest to posttest ES in muscular strength was (chi = 1.4 +/- 1.4; 95% confidence interval, 0.41-3.8; p < 0.001). The results of 2 x 2 analysis of variance revealed simple main effects for age, training status (trained vs. untrained), and research design (p < 0.001). No significant main effects were found for sex, program duration, and set end point. Significant interactions were found for training status and program duration (6-16 weeks vs. 17-40 weeks) and number of sets performed (single vs. multiple). The data indicated that trained individuals performing multiple sets generated significantly greater increases in strength (p < 0.001). For programs with an extended duration, multiple sets were superior to single sets (p < 0.05). This quantitative review indicates that single-set programs for an initial short training period in untrained individuals result in similar strength gains as multiple-set programs. However, as progression occurs and higher gains are desired, multiple-set programs are more effective.     

Instrumental and Non-Instrumental Evaluation of 4-Meter Walking Speed in Older Individuals

BackgroundManual measurement of 4-meter gait speed by a stopwatch is the gold standard test for functional assessment in older adults. However, the accuracy of this technique may be biased by several factors, including intra- and inter-operator variability. Instrumental techniques of measurement using accelerometers may have a higher accuracy. Studies addressing the concordance between these two techniques are missing. The aim of the present community-based observational study was to compare manual and instrumental measurements of 4-meter gait speed in older individuals and to assess their relationship with other indicators of physical performance.MethodsOne-hundred seventy-two (69 men, 103 women) non-disabled community-dwellers aged ≥65 years were enrolled. They underwent a comprehensive geriatric assessment including physical function by Short Physical Performance Battery (SPPB), hand grip strength, and 6-minute walking test (6MWT). Timed usual walking speed on a 4-meter course was assessed by using both a stopwatch (4-meter manual measurement, 4-MM) and a tri-axial accelerometer (4-meter automatic measurement, 4-MA). Correlations between these performance measures were evaluated separately in men and women by partial correlation coefficients.ResultsIn both genders, 4-MA was associated with 4-MM (men r = 0.62, p<0.001; women r = 0.73, p<0.001), handgrip strength (men r = 0.40, p = 0.005; women r = 0.29, p = 0.001) and 6MWT (men r = 0.50, p = 0.0004; women r = 0.22, p = 0.048). 4-MM was associated with handgrip strength and 6MWT in both men and women. Considering gait speed <0.6 m/s as diagnostic of dismobility syndrome, the two methods of assessment disagreed, with a different categorization of subjects, in 19% of men and 23% of women. The use of accelerometer resulted in 29 (13 M, 16 F) additional diagnoses of dismobility, compared with the 4-MM.ConclusionsIn an older population, the concordance of gait speeds manually or instrumentally assessed is not optimal. The results suggest that manual measures might lead to misclassification of a substantial number of subjects. However, longitudinal studies using standardized and validated procedures aimed at the comparison of different techniques are needed before recommending the use of accelerometers in comprehensive geriatric assessment.     

Effect of strength training and the practice of Alpine skiing on bone mass density, growth, body composition, and the strength and power of the legs of adolescent skiers

This work examines the influence of practicing strength training and Alpine skiing over 2 years on bone mineral density (BMD), growth, body composition, and the strength and power of the legs of adolescent skiers. The study subjects were 20 adolescent skiers (10 girls and 10 boys) and 19 sedentary adolescents (9 girls and 10 boys), all 13-16 years of age. The BMDs of the lumbar column (L2-L4) and hip (neck of the femur, trochanter, and Ward's triangle) were determined by dual x-ray photon absorptiometry at the beginning and end of the experimental period. The increase in height and the percentage fat and muscular masses of the subjects were also recorded, as was their ability to jump (countermovement jump [CMJ]), their leg strength and power (squat test), and their leg anaerobic power (continuous jump test [CMJ15″]). No significant differences were seen in the increase in height, body weight, or percentage fat mass between the skiers and sedentary subjects, although the boy skiers showed a significant increase in percentage muscular mass (p < 0.05) compared to the sedentary boys. The improvement in the values of the different CMJ variables was significantly greater among the boy skiers than among the sedentary boys (p < 0.001-0.01). The same was true for the girls (p < 0.001), except for CMJ15″. The skiers experienced a significantly greater increase in L2-L4 BMD than the sedentary subjects (boys p < 0.05; girls p < 0.01). These results suggest that Alpine skiing combined with rational strength training involves no special risk for the physical development of young people, has a positive effect on the power and the percentage of muscle mass in the legs, and helps to have a higher bone density in the lumbar spine (L2-L4).     

Sensory lateralization in pain subjective perception for noxious heat stimulus

The aim of the present study was to identify and characterize hemispheric lateralization for pain intensity perception. A sample of 351 healthy volunteers was tested by the immersion of the right hand for 10 s followed by the same test for the left hand (RL group; n = 199) or in a random sequence (RND group; n = 152) into a water bath (48 degrees C, 15 s). Pain intensity was self-reported by the Visual Analogue Scale (VAS). The motor hemispherical Lateralization Index (LI) was obtained by the Edinburgh Inventory. Gender, hand skin fold, interstimulus time and menstrual cycle data in case of female subjects were recorded. The sample, 60.7% females and 39.3% males, 20.4 +/- 0.18 (mean +/- SEM) years old, showed 92.1% right-handed subjects. Left hand VAS was significantly higher than right hand VAS for RL (7.24 +/- 1.31 vs 6.74 +/- 1.52; p < 0.01) and RND (7.24 +/- 0.82 vs 6.73 +/- 1.25; p < 0.01) both for right- and left-handed subjects. A low but significant correlation for VAS scores and LI was found (r = 0.14; p < 0.05 or r = 0.18; p < 0.05, for left or right hand, respectively). Skin fold was statistically similar in both hands (p > 0.05) being highly correlated with each other (r = 0.68; p < 0.05). Pain subjective perception was not correlated to interstimulus time (r = -0.01; p > 0.05). Females showed significantly higher values than males for both left and right hand VAS scores. Periovulatory phase VAS value was significantly higher than luteal phase VAS only for the right hand test (7.57 +/- 0.20 vs 6.47 +/- 0.33; p < 0.01). The results of the present study suggest a lateralization of pain intensity perception to the right hemisphere not correlated with the motor hemispheric lateralization.     

Work volume and strength training responses to resistive exercise improve with periodic heat extraction from the palm

Body core cooling via the palm of a hand increases work volume during resistive exercise. We asked: (a) "Is there a correlation between elevated core temperatures and fatigue onset during resistive exercise?" and (b) "Does palm cooling between sets of resistive exercise affect strength and work volume training responses?" Core temperature was manipulated by 30-45 minutes of fixed load and duration treadmill exercise in the heat with or without palm cooling. Work volume was then assessed by 4 sets of fixed load bench press exercises. Core temperatures were reduced and work volumes increased after palm cooling (Control: Tes = 39.0 ± 0.1° C, 36 ± 7 reps vs. Cooling: Tes = 38.4 ± 0.2° C, 42 ± 7 reps, mean ± SD, n = 8, p < 0.001). In separate experiments, the impact of palm cooling on work volume and strength training responses were assessed. The participants completed biweekly bench press or pull-up exercises for multiple successive weeks. Palm cooling was applied for 3 minutes between sets of exercise. Over 3 weeks of bench press training, palm cooling increased work volume by 40% (vs. 13% with no treatment; n = 8, p < 0.05). Over 6 weeks of pull-up training, palm cooling increased work volume by 144% in pull-up experienced subjects (vs. 5% over 2 weeks with no treatment; n = 7, p < 0.001) and by 80% in pull-up na?ve subjects (vs. 20% with no treatment; n = 11, p < 0.01). Strength (1 repetition maximum) increased 22% over 10 weeks of pyramid bench press training (4 weeks with no treatment followed by 6 weeks with palm cooling; n = 10, p < 0.001). These results verify previous observations about the effects of palm cooling on work volume, demonstrate a link between core temperature and fatigue onset during resistive exercise, and suggest a novel means for improving strength and work volume training responses.     

Association of Alanine Aminotransferase Levels (ALT) with the Hepatic Insulin Resistance Index (HIRI): a cross-sectional study

ABSTRACT: BACKGROUND: The association between serum alanine aminotransferase (ALT) levels and hepatic insulin resistance (IR) has been evaluated with the hyperinsulinemic-euglycemic clamp. However, there is no information about the association of ALT with the Hepatic Insulin Resistance Index (HIRI). The aim of this study was to evaluate the association between serum ALT levels and HIRI in subjects with differing degrees of impaired glucose metabolism. METHODS: This cross-sectional study included subjects that had an indication for testing for type 2 diabetes mellitus (T2DM) with an oral glucose tolerance test (OGTT). Clinical and biochemical evaluations were carried out including serum ALT level quantification. HIRI was calculated for each participant. Correlation analyses and lineal regression models were used to evaluate the association between ALT levels and HIRI. RESULTS: A total of 324 subjects (37.6 % male) were included. The mean age was 40.4 [PLUS-MINUS SIGN] 14.3 years and the mean body mass index (BMI) was 32.0 [PLUS-MINUS SIGN] 7.3 kg/m2. Individuals were divided into 1 of 5 groups: without metabolic abnormalities (n = 113, 34.8 %); with the metabolic syndrome (MetS, n = 179, 55.2 %), impaired fasting glucose (IFG, n = 85, 26.2 %); impaired glucose tolerance (IGT, n = 91, 28.0 %), and T2DM (n = 23, 7.0 %). The ALT (p < 0.001) and HOMA2-IR (p < 0.001) values progressively increased with HIRI quartiles, while ISI-Matsuda (p < 0.001) progressively decreased. After adjustment for sex, age, and BMI, we identified a significant correlation between HIRI and ALT in persons with the MetS (r = 0.22, p = 0.003), IFG (r = 0.33, p < 0.001), IGT (r = 0.37, p < 0.001), and T2DM (r = 0.72, p < 0.001). Lineal regression analysis adjusting for age, HDL-C, TG and waist circumference (WC) showed an independent association between ALT and HIRI in subjects with the MetS (beta = 0.07, p = 0.01), IFG (beta = 0.10, p = 0.02), IGT (beta = 0.09, p = 0.007), and T2DM (beta = 0.31, p = 0.003). This association was not identified in subjects without metabolic abnormalities. CONCLUSIONS: ALT levels are independently associated with HIRI in subjects with the MetS, IFG, IGT, and T2DM. The ALT value in these subjects may be an indirect parameter to evaluate hepatic IR.     

Strength and power profiles of the lower and upper extremities in master throwers at different ages

Thirty-two master athletes (shot put, discus, and hammer throw) were divided into 4 groups according to their age (T40 [40 years of age], 50 [50 years of age], 60 [60 years of age], and 75 [75 years of age]). Twenty-eight age-matched men served as controls (C40 [40 years of age], 50 [50 years of age], 60 [60 years of age], and 75 [75 years of age]). The subjects were tested for maximal isometric strength of the lower and upper extremities. Power was measured by performing jump squats and bench press in the Smith machine with the load of 60% of 1 repetition maximum. Electromyographic (EMG) activity was recorded from 6 different muscles. The muscle thickness of vastus lateralis and intermedius (VL+VI) and triceps brachii (TB) was measured by ultrasound. Maximal strength differed (p < 0.05- 0.001) in all testing actions between T40 and T60 and T40 and T75 as well as between T and C groups. Both VL+VI and TB thickness in T40 was greater (p < 0.05-0.01) than in T60 and T75 and in T was larger than in C groups. Average force during the first 500 milliseconds (ms) was higher (p < 0.05-0.001) in T40 compared to T50, T60, and T75 in bilateral leg extension, biceps curl, and especially in unilateral knee flexion. T40 produced higher power than the other groups (p < 0.05-0.001). The relative agonist EMG activation (VL) in leg extension during the first 100 ms compared to maximum activation was lower (p < 0.05) in T50, T60, and T75, but not in T40. The present data indicate that maximal strength and muscle thickness as well as explosive strength and power characteristics decline with aging also in master athletes who carry out strength training and throwing exercises actively over several decades. Nevertheless, in master athletes, maximal strength and muscle mass as well as explosive force production of the upper and lower extremities seem to be at remarkably higher levels than those recorded for age-matched control men.     

Concentrations of copper, zinc and various elements in serum of patients with bronchial asthma.

In this study, serum copper, zinc, magnesium, iron and calcium concentrations were investigated in 40 patients with bronchial asthma (BA) and in 43 healthy subjects. Copper and calcium levels were found to be increased in patients with BA compared to the control group (p < 0.001 and p < 0.001 respectively). On the other hand, the serum zinc level was significantly lower in healthy subjects (p < 0.01). No changes were found in serum magnesium and iron levels in patients with BA compared to controls. In addition to various elements, certain serum proteins such as albumin, transferrin and ferritin were also assessed to determine whether there was a relationship between the elements and proteins in patients with BA. There was only a significant decrease in albumin concentration in patients with BA (p < 0.05).     

Effects of strength training on submaximal and maximal endurance performance capacity in middle-aged and older men

Effects of a 16-week progressive strength-training program on blood lactate accumulation (LA), maximal workload (W(max)) attained during progressive cycling exercise, maximum half-squat (1RM(HS)), muscle cross-sectional area of the quadriceps femoris muscle group (CSA(QF)), and serum hormone concentrations were examined in 11 middle-aged (46 year old [M46]) and 11 older (64 year old [M64]) men. During the 16 weeks of training, significant increases were observed in 1RM(HS) in M46 and M64 (41-45%; p < 0.001). The muscle CSA(QF) increased (13-11%; p > 0.01) for both groups. The first 8 weeks of training led to significant increases in W(max) (6-11%; p < 0.001) and decreases in submaximal (LA) in both groups, but no further training-induced changes were observed during the subsequent 8 weeks of training. Statistically significant relationships were observed in M64 and in the combined group M46 + M64 between the training-induced changes observed in W(max) and serum testosterone-cortisol and free-testosterone-cortisol ratios, whereas in M46 the respective correlations values did not reach statistically significant levels. These data indicate that strength training results in a significant improvement in maximal and submaximal endurance during the first 8 weeks of strength training in both age groups, related in part to the intensity and the volume of resistance training used and to the training status of the subjects. The relationships found in this study between various indices of cycling testing and serum hormone concentrations after strength training suggest that maximal incremental cycling might be used as an additional test to detect anabolic-catabolic responses to prolonged strength training in middle-aged and older men.     

Sensory recovery in a split skin graft: pinprick or a thermal sensory analyzer?

Sensory return in a split skin graft is an important factor in the protection of this graft from injury. Hence, three tests were compared: (1) the standard pain test using a simple pin, (2) the cold pain test, and (3) the hot pain test. Both the hot and cold pain tests were performed using the thermal sensory analyzer device. Thirteen patients were investigated; all had split skin grafts applied directly onto deep fascia after malignant melanoma excision on the lower limb. The period after grafting ranged from 4 to 15 years, and the mean age was 46.5 years. The normal contralateral side of each patient was used as the control for that patient. The results were collected in simple data tables and were analyzed using paired t tables for small samples with the level of significance set at p < 0.05. The standard pain test demonstrated that the split skin grafts applied on deep fascia did not recover sensation, even 15 years after surgery (p < 0.001). The hot and cold pain tests were both in agreement with the standard pain test at p < 0.001 and p < 0.03, respectively. The standard pain test is usually performed, as described in this study, using a pin, which is cheap and readily available in any plastic surgery and burn clinic. However, the cold and hot pain tests as performed here using the thermal sensory analyzer device are accurate but are costly, cumbersome, and not available in all clinics except for highly specialized units. Hence, the author would like to dispel the myth that the standard pain test is inaccurate. This might be so in testing sensation in "normal" skin but not in testing the recovery of sensation in a skin graft.     

Evaluation of a method for bimanual testing coordination of hand grip and load forces under isometric conditions

The purpose of the study was to evaluate a method for testing bimanual prehension based on a novel experimental device. The device consists of two handles allowing for simultaneous measurement of bimanual hand grip forces (GF) and different patterns of load forces (LF) exerted during compression and tension along the longitudinal axis. In order to assess the reliability of the obtained measures, eight healthy subjects were tested over three consecutive test, while three moderately impaired neurological patients were tested once. In healthy subjects, high coordination was observed between GFs and LFs, as well as between two GFs and two LFs. The results also suggest a satisfactory task performance in regards to exerting the instructed LF profile, as well as a sufficient, but not excessive GF. The reliability of most of the assessed variables proved to be either moderate or high. When compared to healthy subjects, the data obtained from neurological patients mainly revealed irregular patterns of LFs, excessive GFs, as well as a relatively weak relationship between GFs and LFs. It was concluded that the evaluated methodological approach can be applied not only to explore uni- and bi-manual coordination of arm and hand grip forces in various prehensile activities, but also to serve as a basis for future development of specific clinical tests for neurological patients and other populations that demonstrate impaired hand function.     

Thigh-muscles strength training, dance exercise, dynamometry, and anthropometry in professional ballerinas

The purpose of the present study was to assess the effects of 12 weeks of quadriceps and hamstring strength training on torque levels after a dance exercise and on selected anthropometric parameters. The sample consisted of 22 (ages, 25 +/- 1.3 years) full-time professional ballerinas who were randomly assigned into experimental (n = 12) and control (n = 10) groups. A dance routine designed to cause fatigue within 5 minutes, isokinetic dynamometry, and anthropometric assessments were conducted before and after strength training in both groups. Before strength training, the dance routine resulted in significant reductions of hamstring (p < 0.001) and quadriceps (p < 0.001) peak torques in both subject groups. However, after strength training, only control subjects demonstrated such torque decrements (p < 0.001) after the dance routine. Furthermore, the experimental group revealed greater knee extension (119 vs. 138 N.m; p < 0.001) and flexion (60 vs. 69 N.m; p < 0.001) torques, smaller sum of skinfolds (33.6 vs. 27.8 mm; p < 0.01), more fat-free mass (37.7 vs. 39.4 kg; p < 0.05), but unchanged body mass (p > 0.05) and thigh circumferences (p > 0.05). A negative relationship (p < 0.001) was found between initial strength levels and improvements measured at the end of the 12-week program. These results suggest that supplementary strength training for hamstring and quadriceps muscles is beneficial to professional ballerinas and their dancing; weaker individuals are more likely to benefit from such regimens than their stronger counterparts, whereas increases in thigh-muscle strength do not alter selected aesthetic components.     

Evaluation of a new anaerobic power testing system

The purpose of this study was to evaluate the reliability of a new anaerobic athletic performance system. This system is proposed to assess vertical jump height, anaerobic power through repetitive jumping, and reaction to both an auditory and visual stimulus. One hundred twenty-three subjects (92 men and 31 women; mean +/- SD: age, 20.5 +/- 2.1 years; body weight, 83.1 +/- 20.4 kg; height, 176.0 +/- 9.2 cm) volunteered to participate. To assess reliability of the new testing device, subjects were tested on 3 separate occasions (T1, T2, and T3). At least 72 hours but not more than 1 week separated each laboratory visit. During each testing session subjects performed a countermovement jump (CMJ), a 30 consecutive jumps anaerobic power test (30JT), and reaction to both an auditory and visual stimulus. Results showed no differences between T1, T2, and T3 in either CMJ height or 30JT assessments. However, reaction to an audible or visual stimulus significantly improved during each testing session. Intraclass reliability of the CMJ and the 30JT was greater than 0.96 across the 3 trials. Pearson correlation coefficients of r > 0.90 were seen for the CMJ and 30JT, indicating a high test-retest reliability. The test-retest reliability for the reaction tests were lower (r ranging from 0.72 to 0.83). A Bland-Altman plot showed limited agreement between methods of vertical jump height assessment. Results indicate that this new testing device shows high reliability to assess both CMJ height and anaerobic power. In addition, anaerobic power assessment in a jump test provides a specific measure of anaerobic power for many sports incorporating similar performance patterns.     

The effect of lactate concentration on the handgrip strength during judo bouts

Judo is a combat sport in which the athletes attempt to hold and control their adversary through gripping techniques (kumi-kata) to apply opportune throwing techniques (nage-waza). Twelve male judo athletes, representing national teams, were recruited to investigate the changes in the maximal isometric strength in both hands before (pre) and after (post) 4 judo bouts and its relationship with the maximal blood lactic acid concentration. The subjects performed a maximal isometric contraction with each hand immediately before and after each bout. A blood sample was taken at 1, 3, and 14 minutes after each bout, and the lactic acid concentration was determined. An overall effect of the successive bouts on the maximal isometric handgrip strength of prebouts was observed for both hands (p < 0.05) but not in that of postbouts (p > 0.05). The dominant hand showed an overall decrease in the maximal isometric strength because of the bout, with the decrease being significant for the first, third, and fourth bouts (p < 0.05). The nondominant hand only showed a significant decrease in the first prebout and postbout (p < 0.05). We observed an inverse relationship between the maximal isometric handgrip strength of postbouts and maximum lactic acid concentration (Lacmax), and between the maximal isometric handgrip strength of postbouts and the lactic acid concentration at minute 14 of the recovery period (Lac14) (p < 0.05). These results show that successive judo bouts significantly reduce the maximal isometric strength of both hands and may suggest that fatigue of each hand depends on different factors. An enhanced understanding of the behavior of the isometric handgrip strength, and the factors that affect grip fatigue during judo bouts in the dominant and nondominant hands, can aid coaches in developing optimal training and exercise interventions that are aimed at mitigating decreases in the capacity of judo athletes to perform a grip.