Reduced tissue creatine levels in patients with long COVID-19: A cross-sectional study

Total creatine concentration in the skeletal muscle and brain of long COVID patients were significantly lower when compared to the reference values for the general population, as measured with proton magnetic resonance spectroscopy at 1.5-T in vastus medialis muscle, thalamus, and three bilateral cerebral locations across the white and gray matter.

Age-Related Changes in Serum Guanidinoacetic Acid in Women

Guanidinoacetic acid (GAA) is a fundamental intermediate in cellular bioenergetics, with circulating levels of GAA often reflects disturbances in its conversion due to many intrinsic and extrinsic factors, including gender or age. Here, we evaluated serum GAA in 172 healthy women aged 18 to 65 years, with age found to significantly predict serum GAA concentrations (r=0.29; P=0.03). This perhaps nominates serum GAA as a novel gender-specific proxy of impaired bioenergetics with aging.

Molecular hydrogen in sports medicine: new therapeutic perspectives

In the past 2 decades, molecular hydrogen emerged as a novel therapeutic agent, with antioxidant, anti-inflammatory and anti-apoptotic effects demonstrated in plethora of animal disease models and human studies. Beneficial effects of molecular hydrogen in clinical environment are observed especially in oxidative stress-mediated diseases, such as diabetes mellitus, brain stem infarction, rheumatoid arthritis, or neurodegenerative diseases. A number of more recent studies have reported that molecular hydrogen affects cell signal transduction and acts as an alkalizing agent, with these newly identified mechanisms of action having the potential to widen its application in clinical medicine even further. In particular, hydrogen therapy may be an effective and specific innovative treatment for exercise-induced oxidative stress and sports injury, with potential for the improvement of exercise performance. This review will summarize recent research findings regarding the clinical aspects of molecular hydrogen use, emphasizing its application in the field of sports medicine.

Prediction of adult height by Tanner-Whitehouse method in young Caucasian male athletes

BACKGROUND

Although the accuracy of final height prediction using skeletal age development has been confirmed in many studies for children treated for congenital primary hypothyroidism, short normal children, constitutionally tall children, no studies compared the predicted adult height at young age with final stature in athletic population.

AIM

In this study, the intention was to investigate to what extent the Tanner-Whitehouse (TW) method is adequate for prediction of final stature in young Caucasian male athletes.

DESIGN

Prospective observational study.

METHODS

Plain radiographs of the left hand and wrist were obtained from 477 athletic children (ranging in age from 8.0 to 17.9 years) who came to the outpatient clinic between 2000 and 2011 for adult height estimation, with no orthopedic trauma suspected. Adult height was estimated using bone age rates according to TW method. Height was measured both at baseline and follow-up (at the age of 19 years).

RESULTS

No significant difference was found between the estimated adult height (184.9 ± 9.7 cm) and final stature (185.6 ± 9.6 cm) [95% confidence interval (CI) 1.61-3.01, P = 0.55]. The relationship between estimated and final adult height was high (r = 0.96). Bland-Altman analysis confirmed that the 95% of differences between estimated adult height and final stature lie between limits of agreement (mean ± 2 SD) (-5.84 and 4.52 cm).

CONCLUSION

TW method is an accurate method of predicting adult height in male normal-growing athletic boys.

Correlation between explosive strength, aerobic power and repeated sprint ability in elite basketball players

AIM

The aim of this study was to examine the relationship between explosive strength and aerobic power with basketball-specific repeated sprint ability in elite male basketball players.

METHODS

Twenty-four elite basketball players (age 22.2±3.4 years, height 197.1±6.2 cm, weight 95.7±8.8 kg; training experience 11.0±3.1 years; mean±SD), participated in the study. Subjects performed countermovement jump (CMJ) test and incremental pseudo-ramp test protocol with measured CMJ height and VO2max, respectively. Specific repeated sprint ability (RSA) test was conducted, with total sprinting time (summation of 10 sprint times - RSAtot) and sprint decrement (fatigue index - RSAFI) calculated.

RESULTS

Significant decrements in sprint performance from the eight 30-m sprint (P<0.05) were observed. Strong inverse correlation was found between CMJ and RSAtot (r=-0.74, P<0.01). No significant correlation was found between VO2max and RSA outcomes neither between CMJ and RSAFI.

CONCLUSION

CMJ is a predictor of RSA in elite basketball players. It seems that coaches and strength and conditioning professionals should devote additional time for explosive strength development in elite basketball players during preparatory period to enhance RSA performance.

Systolic right ventricular adaptive changes in athletes as predictors of the maximal functional capacity: a pulsed tissue Doppler study

AIM

The aim of this study was to extend the analysis of the systolic right ventricular (RV) adaptation to combined endurance and strength training, to assess the utility of tissue Doppler imaging in detecting the degree of these changes and to find independent RV predictors of the maximal functional capacity.

METHODS

Standard Doppler and TDI were used to assess cardiac parameters at rest in 37 elite male athletes (16 wrestlers, 21 water polo players) and 20 sedentary subjects of similar age. Progressive maximal test on treadmill was used to assess VO2max. The obtained parameters were adjusted for HR, FFM, and BSA.

RESULTS

Wrestlers showed higher VO2max than controls, but lesser than water polo players. RV diameter was larger in athletes. Right atrial pressure (RVE/e) was higher in water polo players than in other groups. Systolic function assessed by tricuspid annular plane systolic excursion (TAPSE) and RVs' was the highest in wrestlers. Global RV systolic parameters myocardial performance index (MPI) and preejection time/ejection time index (PET/ET) were similar. On multivariate analysis systolic parameters were independent predictors of VO2max only in wrestlers: RVs' (beta=3.18, P=0.001) and RV ET (beta=2.32, P=0.001). RVE/e` correlated with RVs' (r=-0.57, P=0.000). TAPSE correlated with RV ET (r=0.32, P=0.015) and RVs` (beta=0.28, P=0.033).

CONCLUSION

Systolic function assessed by TAPSE and RVs` has more improved in less endurance athletes. RVs`and TDI ejection time predict VO2max in wrestlers, and possibly in other athletes with lesser right atrial pressure. TDI enables quantifying RV adaptation degree in athletes, but complementary to M-mode technique.

Daily timing of salivary cortisol responses and aerobic performance in lean and obese active females

The main aim of the present study was to study the effects of morning and afternoon physical activities on cortisol responses in obese and lean women. Twenty women volunteered to participate in this study. Subjects were divided into an obese group (BMI =29.1 kg/m2) and a lean group (BMI =19 kg/m2). All subjects participated in an exercise program consisting of treadmill running at 65+/-2 % VO2max until exhaustion. In order to study effects of circadian rhythm, exercise was performed at a similar intensity and in similar environmental conditions at both 8:00 AM and 4:00 PM. Saliva specimens were collected at rest 20 minutes before activity and then immediately after the exercise in both morning and afternoon sessions. Morning and afternoon exercise resulted in a significant increase in salivary cortisol concentrations compared to basal levels in both lean and obese women (p<0.05), though the change in cortisol concentrations were higher in lean. The aerobic function of lean and obese women in the morning and afternoon showed a significant increase of 13.8 % and 5.9 %; respectively, with lean being consistently higher than obese. In conclusion, the stress response to exercise is related to circadian rhythm and individual's body weight. Based on the results of this study, it is suggested that overweight women perform exercises in the afternoon to minimize the stress response for the exercise volume performed (Tab. 1, Fig. 3, Ref. 39). Full Text in free PDF www.bmj.sk.

Cardiorespiratory fitness and adiposity in overweight and nonoverweight 8-year-old school children

AIM

The objective of the present study was to determine relationship between cardiorespiratory fitness and body fatness in both nonoverweight and overweight 8-year-old school children.

METHODS

The study participants were a 245 healthy second-grade elementary school children aged 8.9 ± 0.4 yrs (125 boys, 120 girls). Anthropometric data (height, body mass, waist circumference, five skinfold thickness) were collected and body fat percentage was calculated. Body Mass Index (BMI) sex- and age-specific cutoff points were used for overweight and obesity definition and children were placed in two groups: overweight/obese and nonoverweight. Aerobic fitness was assessed with the multistage shuttle-run fitness test. Subjects were grouped into high (upper two quintiles) and low (lower two quintiles) aerobic fitness based on age and sex distributions.

RESULTS

BMI, waist circumference, five skinfold thicknesses and total body fat were lower in overweight and obese children with high aerobic fitness in comparison with youths at the same BMI category with low fitness level (P < 0.01). The beneficial effect of high aerobic fitness was also presented in nonoverweight children (P < 0.01). Finally, aerobic fitness was moderately correlated with total body fat in the whole group of subjects (r = -0.48, P < 0.01).

CONCLUSION

Indicators of local and total adiposity were lower in overweight and obese children with high aerobic fitness. Being fit may reduce the hazards of obesity in population of 8-year-old school children.

High aerobic fitness is associated with lower total and regional adiposity in 12-year-old overweight boys

AIM

The objective of the present study was to determine relationship between aerobic (cardiovascular) fitness and body composition in both non-overweight and overweight 12-year-old school boys.

METHODS

A cross-sectional study was conducted in a random sample of 10 elementary schools. The study participants were a 170 healthy fifth-grade elementary school boys aged 11.9±0.4 years. Anthropometric data (height, body mass, waist circumference, abdominal skinfold thickness) were collected according to standard procedure. Total body fat and muscle mass percentage were assessed by bioimpedance analysis. Body Mass Index (BMI) age-specific cutoff points were used for overweight definition and boys were placed in two groups overweight and non-overweight. Aerobic fitness (VO2max) was assessed with the multistage shuttle-run fitness test. Boys were grouped into high (upper two quintiles) and low (lower two quintiles) aerobic fitness based on age distribution.

RESULTS

Waist circumference, abdominal skinfold thickness and total body fat were lower while muscle mass percentage was higher in overweight boys with high aerobic fitness in comparison with boys at the same BMI category with low fitness level (P<0.05). Aerobic fitness was inversely correlated with body fat in the whole group of subjects (r=-0,57, P<0.05), with particularly high correlation between VO2max and muscle mass in overweight boys (r=0.68, P<0.05).

CONCLUSION

Indicators of local and total adiposity were lower in boys with high aerobic fitness. It seems that high aerobic fitness has is positively associated with body composition in overweight boys.

Weekly training volume and hematological status in female top-level athletes of different sports

AIM

The objectives of the present study were: a) to investigate the prevalence of iron depletion and anemia among female top-level athletes from different sports; b) to determine a relationship between serum ferritin levels and training status of female athletes.

METHODS

This study was conducted on 84 female professional athletes who were recruited during preparticipation physical examination. Upon entering the laboratory 10 mL of venous blood was drawn from an antecubital vein into a lavender-top tube for a complete blood count (CBC), serum iron, and transferrin and ferritin levels.

RESULTS

No significant differences between any of the hematological variables were found between groups of different sports. The lowest hemoglobin (Hb), mean corpuscular volume (MCV), serum iron, ferritin and transferrin encountered in the study were Hb of 9.1 g/dL, MCV of 64.5 fL, serum iron of 15 microg/dL, ferritin of 5.4 microg/L, transferrin of 210 microg/dL in a 20-year old female distance runner with functional impairment and iron deficiency anemia. No significant differences were found between female athletes from different sports regarding the prevalence of iron depletion, iron deficiency or iron deficiency anemia (IDA). Serum ferritin level poorly correlate with training duration (r = 0.24) and seems to be inadequate indicator of training tolerance.

CONCLUSION

This study has shown a high prevalence of iron depletion and anemia among female athletes from different sports, with similar incidence in individuals independent of their weekly training volume.

Indicators of iron status in elite soccer players during the sports season

The main aim of the study was to investigate the changes of hematologic status in elite soccer players throughout a competitive season. Study was conducted with 35 male professional soccer players and the measurements were collected at the start of the conditioning period, at the start of the season, in the mid-season and at the end of the season. Blood was drawn from an antecubital vein for a complete blood count, serum iron, and transferrin and ferritin levels. We found significantly higher hematocrit at preseason assessment as compared with other sampling periods (P < 0.05). No other differences were found between any of the hematologic variables during the study. The lowest hemoglobin level, mean corpuscular volume (MCV), serum iron, ferritin and transferrin encountered in the study were Hb of 11.2 g/dl, MCV of 77.9 fl, serum iron of 34 microg/dl, ferritin of 15.1 microg/l, transferrin of 224 microg/dl in a 20-year-old soccer player at the start of the season. The variability of the iron status indicators in elite soccer players seems to be stable and poorly related to training phase during sports season.

Glucosamine administration in athletes: effects on recovery of acute knee injury

The main aim of this study was to examine the effects of 4 weeks of glucosamine administration on the functional ability and the degree of pain intensity in competitive male athletes after acute knee injury. This study was a randomized, double-blind parallel trial of glucosamine (1500 mg per day) or a placebo for 28 days, utilising 106 patients with an acute knee injury. Pain and functional ability were evaluated at the beginning of the study and at 7, 14, 21, and 28 days after starting treatment. Pain intensity at rest and while walking was assessed using a visual analog scale. Passive knee flexibility (flexion and extension) of the injured limb was measured using a modified goniometer, and the degree of knee swelling was measured and compared with the noninjured limb. No significant difference was found between the glucosamine, and placebo group in mean pain intensity scores for resting and walking, and degree of knee swelling at the 7-day, 14-day, 21-day, and 28-day assessment. There was no significant difference between passive knee flexibility at the 7-day, 14-day, and 21-day assessment. After 28 days of treatment the patients from the glucosamine group demonstrated significant improvement in knee flexion and extension as compared with the placebo group.

Estimation of body fat in athletes: skinfolds vs bioelectrical impedance

AIM

The aim of the present study was to compare two different field methods (skinfolds(SKF(vs bioimpedance analysis(BIA) for estimation of body fatness in top-level athletes.

METHODS

This study was conducted with 219 male professional athletes who were recruited during pre-participation physical examination. Skinfold thicknesses at 7 sites were obtained using a Harpenden caliper while total body resistance was measured with a foot-pad bioelectrical impedance analyzer at a fixed signal frequency of 50 kHz and 500 microA.

RESULTS

The athletes showed non-significant difference in body fat percentage (%BF) between the average %BFSKF and %BFBIA (P > 0.05). Average time of assessment per subject was significantly longer during skinfold measurement (P < 0.01) as compared with BIA assessment.

CONCLUSIONS

We found that the estimates of body fat were similar between SKF and BIA with significant correlation (r = 0.96) between methods while BIA method is less time-consuming. In conclusion, the most simple, quick, and inexpensive method of BIA seems to be very useful to the dietitians' routine for assessing body fat in physically active individuals and athletes.