The association between unilateral and bilateral performance-related measures in elite female soccer players: a multifaceted investigation.

Purpose: The present study aimed to investigate a) the associations between bilateral performance utilizing countermovement jump (CMJ), squat jump (SJ), speed and unilateral CMJ, isokinetic peak torque in knee extension and flexion with angular velocities of 60°/s and 180°/s and tensiomyography (TMG) parameters; b) whether the asymmetries derived from unilateral tests are associated with bilateral CMJ, SJ and speed in elite female soccer players. Methods: Thirty-five elite female soccer players (average age: 20 ± 5 years) completed CMJ, SJ, speed, isokinetic muscle strength and TMG tests. Results: Compared to the non-dominant leg, the dominant leg demonstrated greater peak torque output in both knee flexion (7.4%) and knee extension (5.6%) isokinetic tasks, as well as m. vastus medialis contraction time (7.6%), and soccer-specific agility test (4.1%). Conversely, the hamstring to quadriceps peak torque ratio at 180°/s (8.5%) was significantly greater in the non-dominant leg. The associations between CMJ, SJ and speed performance were positive and ranged from weak (r = 0.350) to high (r = 0.710). For speed and TMG-derived variables, correlations were negative and ranged from weak (r = -0.345, p = 0.042, for vastus medialis contraction time) to moderate (r = -0.530, p = 0.001, for biceps femoris contraction time). Furthermore, both bilateral CMJ and SJ negatively correlated with TMG-derived variables, ranging from weak (r = -0.350, p = 0.039, for vastus lateralis contraction time) to moderate (r = -0.537, p = 0.003, for rectus femoris contraction time). Conclusion: The overall significant, albeit inconsistent, correlations between the diverse performance scores obtained highlight the necessity for a multifaceted and thorough diagnostic strategy in female soccer players.

Twelve weeks of combined physical and cognitive intradialytic training preserves alertness and improves gait speed: a randomized controlled trial.

BACKGROUND: Hemodialysis (HD) patients often experience cognitive deficits and reduced mobility. While studies have shown promising results of physical and/or cognitive training in older adults, their effects in HD patients remain understudied. AIMS: This study aimed to evaluate the impact of a 12-week intradialytic training program combining cognitive training with physical exercise on attention domains and spontaneous gait speed (SGS) in HD patients. METHODS: Forty-four HD patients were randomly assigned to either intradialytic cognitive and physical exercise training (EXP group; n = 22) or a standard care control group (CON group; n = 22). The EXP group performed intradialytic cycling and tablet-based cognitive training three days per week for 12 weeks. The primary outcome of the study was performance on the computerized test battery 'Test of Attentional Performance.' Secondary study outcome was patient mobility assessed by the four-meter SGS. Outcomes were assessed pre- and post-intervention. RESULTS: Significant group x time interaction was observed in alertness (F(1,41) = 6.15, p = 0.017) and SGS (F(1,41) = 18.33, p < 0.001) in favor of the EXP group. Within-group analysis revealed a significant pre-post decline in the CON group in alertness test (-26.7 s; p = 0.04) and an improvement of SGS in EXP group (+ 0.07 s; p < 0.001). DISCUSSION: This original study demonstrated that a combined physical and cognitive intradialytic training intervention led to improvements in SGS and preservation in alertness compared to a deterioration in the CON group. CONCLUSION: Findings suggest that the intervention may serve as an effective tool to prevent the physical and cognitive decline in this patient population.

Physical exercise and cognitive training interventions to improve cognition in hemodialysis patients: A systematic review.

Introduction: Patients with chronic kidney disease treated with hemodialysis (HD) have lower cognitive abilities compared to the age-matched healthy population. Recently, physical exercise and cognitive training have been presented as possible interventions to improve cognitive abilities both in the general population and in patients with chronic diseases. To date, there is no general overview of the current knowledge on how these interventions affect cognitive abilities in HD patients and what tests are used to measure these effects. Methods: Three electronic databases were searched for randomized controlled studies of physical exercise or cognitive training interventions that examined effects on cognitive abilities/performance in HD patients. Results: Six articles were included. All included studies used physical exercise as an intervention, with one study also including tablet-based cognitive training. Four studies included an intradialytic approach and two included a home-based intervention. Intervention lasted. A significant intervention effect was observed in three studies compared with the control condition. Conclusion: The present review suggests that physical exercise might improve or at least not worsen cognitive performance in HD patients, whereas the effect of cognitive training has not yet been adequately studied. There is a need for more sensitive and specific cognitive tests to adequately measure the effects of interventions in the HD population.

Evaluation of the Limb Symmetry Index: The Side Hop Test.

The main objective of present study was to evaluate inter-rater reliability and concurrent validity of Side Hop Test stopwatch vs. force plates timing, and to determine the number of sessions and trials required to minimize the effects of learning on Side Hop Test total time and limb symmetry index. Fifteen healthy male physical education students (mean ± SD: age, 23 ± 3 years; height, 181 ± 9 cm; and weight 72 ± 6 kg) participated. Side Hop Test total time (stopwatch and force plates) of left and right leg, and limb symmetry index (force plates) were obtained over seven sessions conducted 5-7 days apart. Time recordings of two raters were similar (t = -0.56, p > 0.05) with high reliability (all ICC >0.99 and CV% <0.1) and no systematic bias when compared to force plate data (p > 0.05; for rater 1 and 2, respectively). Total time improved across the Sessions (F = 25.87, p < 0.01, ω 2 = 0.18) and Trials (F = 68.15, p < 0.01, ω 2 = 0.10), with no significant interaction between factors. No between-leg differences were detected (F = 0.52, p > 0.05, ω 2 = 0.001). Limb symmetry index ranged from 0.999 to 1.055 across all sessions and trials (all p > 0.05 and ω 2 < 0.00). Due to low coefficient of correlation, high interclass correlation coefficient, and the lack in heteroscedasticity, stopwatch measurements are valid to measure total time in the Side Hop Test. Moreover, stopwatch measurements could be reliably used to measure total time in the Side Hop Test, while the test could be administrated with only one experienced rater. Unlike total times, findings on limb symmetry index suggest it could be reliably assessed after seven familiarization sessions.

The muscle contractile properties in female soccer players: inter-limb comparison using tensiomyography.

OBJECTIVE: The present study aimed to: i) determine the contractile properties of the major lower limb muscles in female soccer players using tensiomyography; ii) investigate inter-limb differences; and iii) compare inter-limb differences between different selections and playing positions. METHODS: A total of 52 female soccer players (A team; U19 and U17) were recruited. The vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), gastrocnemius medialis (GM), lateralis (GL) and tibialis anterior (TA) of both lower limbs were evaluated. RESULTS: When the entire sample was assessed regardless of selection or playing position, there were significant inter-limb differences in all measured muscles except BF. Compared to the non-dominant limb, the dominant limb had higher delay time in VL (p=0.008), while showing lower values in VM (p=0.023), GL (p=0.043) and GM (p=0.006). Contraction time was lower in the RF of the dominant limb (p=0.005) and VM (p=0.047), while showing higher values in VL (p=0.036) and TA (p<0.001) as compared to the non-dominant limb. CONCLUSION: Given the differences found between the limbs in the whole sample studied, it is necessary to examine both limbs to gather a more in-depth understanding of underlying mechanisms related to neuromuscular functions in female soccer players. LEVEL OF EVIDENCE: Prognostic study, Level II.

Tissue Flossing Around the Thigh Does Not Provide Acute Enhancement of Neuromuscular Function.

Nowadays, various methods are used for acute performance enhancement. The most recent of these is tissue flossing, which is becoming increasingly popular for both performance enhancement and rehabilitation. However, the effects of flossing on athletic performance have not been clearly demonstrated, which could be due to differences in the methodology used. In particular, the rest periods between the end of the preconditioning activity and the performance of the criterion task or assessment tools varied considerably in the published literature. Therefore, the present study aimed to investigate the effects of applying tissue flossing to the thigh on bilateral countermovement jump performance and contractile properties of vastus lateralis (VL) muscle. Nineteen recreational athletes (11 males; aged 23.1 ± 2.7 years) were randomly assigned to days of flossing application (3 sets for 2 min of flossing with 2 min rest between sets) with preset experimental pressure (EXP = 95 ± 17.4 mmHg) or control condition (CON = 18.9 ± 3.5 mmHg). The first part of the measurements was performed before and after warm-up consisting of 5 min of cycling followed by dynamic stretching and specific jumping exercises, while the second part consisted of six measurement points after flossing application (0.5, 3, 6, 9, 12, 15 min). The warm-up improved muscle response time (VL = -5%), contraction time (VL = -3.6%) muscle stiffness (VL = 17.5%), contraction velocity (VL = 23.5%), jump height (13.9%) and average power (10.5%). On the contrary, sustain time, half-relaxation time and take-off velocity stayed unaltered. Flossing, however, showed negative effects for muscle response time (F = 18.547, p < 0.001), contraction time (F = 14.899, p < 0.001), muscle stiffness (F = 8.365, p < 0.001), contraction velocity (F = 11.180, p < 0.001), jump height (F = 14.888, p < 0.001) and average power (F = 13.488, p < 0.001), whereas sustain time, half-relaxation time and take-off velocity were unaffected until the end of the study protocol regardless of condition assigned and/or time points of the assessment. It was found that the warm-up routine potentiated neuromuscular function, whereas the flossing protocol used in the current study resulted in fatigue rather than potentiation. Therefore, future studies aimed to investigate the dose-response relationship of different configurations of preconditioning activities on neuromuscular function are warranted.

Effects of Intradialytic Cognitive and Physical Exercise Training on Cognitive and Physical Abilities in Hemodialysis Patients: Study Protocol for a Randomized Controlled Trial.

The prevalence of cognitive impairment in hemodialysis (HD) patients is extremely high. Despite the well-documented benefits of interventions on cognitive function, there is a widespread call for effective strategies that will show the long-term consequences in patients undergoing dialysis. The aim of this research protocol was to investigate the effect of cognitive training combined with physical exercise on cognitive function, physical performance, and frailty indicators in the HD population. We will conduct a randomized controlled intervention trial to examine the effects of a combined non-pharmacological intervention in the form of intradialytic physical exercise and intradialytic cognitive training on cognitive function, indicators of frailty, and physical performance measures in HD patients. The group of patients receiving the study intervention will be compared to the control group receiving standard HD care. The duration of the intervention will be 12 weeks. We will use sensitive instruments (cognitive domain tests) to assess cognitive functions. The primary outcome of the study at 12 weeks will be performance on the Alertness subtest of the computerized Test of Attentional Performance. Secondary study outcomes are: Performance in other domains of cognitive function (executive function, psychomotor speed, information processing efficiency, working memory, and attention), physical fitness (10 repetition sit-to-stand test, timed up and go test, handgrip strength test, spontaneous gait speed, and stork balance test), and assessment of frailty (Edmonton Frail Scale). Study outcomes will be assessed at baseline, immediately after the 12-week intervention, and 6 months after the end of the study without specific further intervention (retention effect assessment). This study will be among the first to test the synergistic effects of a uniquely designed physical exercise and cognitive training intervention on functional status in HD patients. We believe our results will contribute to dementia prevention research by demonstrating the long-term efficacy of our combined intervention. Clinical Trial Registration: ClinicalTrials.Gov, NCT05150444.

Effects of Resistance Training With Constant, Inertial, and Combined Loads on Muscle Power and Strength Output.

The aim of this study was to investigate the resistance-specific gains in muscle power and strength (1RM) following the training of maximum bench-press throws (BPT) against constant, inertial, and combined resistance. Forty-eight male participants (age 20.5 ± 2.0 years) were randomly assigned to the constant, inertial, combined resistance, or control group. Participants underwent 8 weeks of training of BPT against the loads that corresponded to the different effects of mass of 40 kg (∼50% of 1RM). The gains in average and maximum power, and 1RM were significant in all experimental groups (P < 0.01), but not in the control group (P > 0.1). Relative gains in the average (26.3 ± 9.8%) and maximum power (25.2 ± 9.8%) were larger than that in the 1RM (mean 7.2 ± 6.9%; both P < 0.001). The gains in the average (F 4, 66 = 6.0; P < 0.01) and maximum power (F 4, 66 = 4.7; P < 0.01) were higher when tested against the training-specific resistance than when tested against the remaining two resistance types. Differences in 1RM among experimental groups were not significant (P = 0.092). The most important and rather novel finding of the study is that the training against the weight and inertial resistance, and their combination results in resistance-specific gains in muscle power, although the overall gains muscle strength and power remain comparable across the training protocols.

Accelerometry Correlates in Body Composition, Physical Fitness, and Disease Symptom Burden: A Pilot Study in End-Stage Renal Disease.

There is strong evidence that hemodialysis (HD) patients with a sedentary lifestyle have a higher risk of death compared to peers who engage in regular physical activity. Therefore, monitoring physical activity is of utmost importance. However, there is a lack of data on objectively measured physical activity behaviors in HD patients. Therefore, this study aimed to objectively measure physical activity in HD patients throughout the week, with particular attention to dialysis and non-dialysis days. We also examined how objectively measured physical activity correlated with physical fitness, body composition, and disease burden. Daily physical activity, body composition, serum parameters, comorbidity index, sit-to-stand, and hand-grip strength tests were measured in 14 HD patients. Daily physical activity was measured using the Actigraph GT9X accelerometer. The Dialysis Symptom Index questionnaire was also used. We found significant differences in anthropometric variables (weight, body mass index, overhydration, lean tissue index, and fat tissue index, all p < 0.05) and phase angle (p < 0.01) between HD patients reaching and patients not reaching physical activity guidelines for patients with chronic diseases. HD patients showed to be less active during dialysis days compared to non-dialysis days as indicated in sedentary time (-11.7%; p = 0.001), light (-47.3%; p = 0.003), moderate (-51.5%; p = 0.001), moderate to vigorous (-49.3%; p = 0.001), and vigorous (-34.3%; p = 0.067) physical activity. No significant correlations were found among serum parameters, symptom burden, and comorbidity burden, but a very large and positive correlation was found between phase angle and total moderate to vigorous physical activity (p < 0.01). Our findings support the need to implement physical activity on dialysis days in HD units to mitigate the effects of sedentary behavior. Prospective, long-term studies evaluating the use of accelerometers in HD patients and their effects on physical activity are needed.

Quality of Life and Physical Activity of Persons with Spinal Cord Injury.

The higher quality of life of people with spinal cord injury is closely related with their reintegration into the social environment. Social reintegration is a demanding and complex process, requiring individuals to become active again and acquire age-, gender-, and culture-appropriate roles and social status. It also involves independence and productive behavior as part of multiple interpersonal relationships with family, friends, and others. In order to establish whether individuals with spinal cord injury who are physically active subjectively rate their quality of life to be higher compared to those who are not, sixty-two respondents from Slovenia with spinal cord injury were interviewed. Thirty-one of them were physically active, and 31 were not. The level of injury of the responders was from Th6-Th12. The participants gave the highest assessments to their interpersonal relationships, and the lowest to their satisfaction with material prosperity. Data comparison showed that subjective estimates in all areas of quality of life are higher in respondents who were involved in physical activity after their injury. The results may encourage persons with spinal cord injury to participate more often in sports programs, and also encourage others to do so.

Palm Temperature Differences after Static and Dynamic Load on High Bar.

Thermal imaging is used in various fields of industry and research to measure temperature and its possible differences. Since there is a lack of research and literature on palm temperatures and prevention of blisters on hands, our question was how palm temperature differs in human hands after different loads (Hang and Swing in Hang) for 30 s on a high bar. Thirty-eight students from the Faculty of Sport at the University of Ljubljana were measured with a high-quality thermal imaging camera. Palm temperatures were measured before the load was applied, immediately after and every 30 s for a period of 5 min after the load. Each hand was divided into nine different regions of interest (ROIs). Mean (XA), standard deviation (SD), maximum and minimum, and number of pixels were calculated. We found that there was no difference between the left and right hand. The temperature right after the load was applied decreased significantly for both loads and then increased above the level before the load was applied. After the static load, the temperature reached a constant higher level after 3 min. After the dynamic load, the temperatures continued to increase throughout the measurement period. Further investigation is needed to determine the time period in which the hand temperature reaches the temperature before the load is applied.

Central TSH Dysregulation in a Patient with Familial Non-Autoimmune Autosomal Dominant Hyperthyroidism Due to a Novel Thyroid-Stimulating Hormone Receptor Disease-Causing Variant.

Background and Objectives. Familial non-autoimmune autosomal dominant hyperthyroidism (FNAH) is a rare cause of childhood hyperthyroidism. It is caused by the thyroid-stimulating hormone receptor (TSHR) gene variants. So far, only around 40 families with FNAH have been reported. Patients with activating TSHR variants demonstrated the same classical signs and symptoms of hyperthyroidism as seen in patients with Graves' disease. Since 2012, ablative therapy is recommended to avoid relapses of hyperthyroidism and its consequences. Case Presentation. We presented a young adult male patient with a novel heterozygous TSHR disease-causing variant p.Arg418Lys (c.1253G>A) in the exon 10, who presented with a mild but progressive FNAH, with a follow-up since infancy. Discussion. Constantly suppressed TSH, including during the euthyreosis in childhood and hypothyreosis after iodine ablation therapy, suggested central dysregulation of the TSH secretion.

Physical Activity and Quality of Life in Hemodialysis Patients and Healthy Controls: A Cross-Sectional Study.

Hemodialysis (HD) patients have lower functional abilities compared to healthy people, and this is associated with lower physical activity in everyday life. This may affect their quality of life, but research on this topic is limited. Therefore, the present study aimed to determine the relationship between habitual physical activity and quality of life in HD patients and healthy controls. Ninety-three HD patients and 140 controls participated in the study. Quality of life was assessed using a 36-item medical outcomes study short-form health survey (SF-36). Human Activity Profile (HAP) was used to assess habitual physical activity. The adjusted activity score (AAS) from HAP, age, gender, fat tissue index (FTI), lean tissue index (LTI), and Davies comorbidity score were analyzed as possible predictors of the Physical Component Summary (PCS) of the SF-36. Three sequential linear models were used to model PCS. In Model 1, PCS was regressed by gender and age; in Model 2 the LTI, FTI, and Davies comorbidity scores were added. Model 3 also included AAS. After controlling for age and gender (ModelHD 1: p = 0.056), LTI, FTI, and Davies comorbidity score effects (ModelHD 2: p = 0.181), the AAS accounted for 32% of the variation in PCS of HD patients (ModelHD 3: p < 0.001). Consequently, the PCS of HD patients would increase by 0.431 points if the AAS increased by one point. However, in healthy controls, AAS had a lower impact than in the HD sample (B = 0.359 vs. 0.431), while the corresponding effects of age and gender (ModelH 1: p < 0.001), LTI, FTI, and Davies comorbidity score (ModelH 2: p < 0.001) were adjusted for. The proportion of variation in PCS attributed to AAS was 14.9% (ModelH 3: p < 0.001). The current study results showed that physical activity in everyday life as measured by the HAP questionnaire is associated to a higher degree with the quality of life of HD patients than in healthy subjects. Routine physical activity programs are therefore highly justified, and the nephrology community should play a leading role in this effort.

Hypercholesterolemia in Two Siblings with Resistance to Thyroid Hormones Due to Disease-Causing Variant in Thyroid Hormone Receptor (THRB) Gene.

Resistance to thyroid hormone beta (RTHß) is a syndrome characterized by a reduced response of target tissues to thyroid hormones. In 85% of cases, a pathogenic mutation in the thyroid hormone receptor beta (THRB) gene is found. The clinical picture of RTHß is very diverse; the most common findings are goiter and tachycardia, but the patients might be clinically euthyroid. The laboratory findings are almost pathognomonic with elevated free thyroxin (fT4) levels and high or normal thyrotropin (TSH) levels; free triiodothyronin (fT3) levels may also be elevated. We present three siblings with THRB mutation (heterozygous disease-variant c.727C>T, p.Arg243Trp); two of them also had hypercholesterolemia, while all three had several other clinical characteristics of RTHß. This is the first description of the known Slovenian cases with RTHß due to the pathogenic mutation in the THRB gene. Hypercholesterolemia might be etiologically related with RTHß, since the severity of hormonal resistance varies among different tissues and hypercholesterolemia in patients with THRB variants might indicate the relatively hypothyroid state of the liver. We suggest that cholesterol levels are measured in all RTHß patients.

Reducing Aggression and Improving Physical Fitness in Adolescents Through an After-School Volleyball Program.

This study aimed to determine the effects of an after-school volleyball program on aggression and physical fitness in 14-16 years old students. One hundred and seven participants were randomized to a small-sided volleyball (SSV) training group or a control group (CON). The SSV group completed 8 months of small-sided volleyball training twice a week after school in addition to the regular physical education classes. Yo-Yo Intermittent Recovery Level 1 test (YYIRT1), medicine ball throw (MED), vertical jump (VJ), and Buss and Perry's aggression questionnaire were evaluated before and after 8 months of training. Results revealed a significant interaction effect (group × time) in total sample for physical aggression [F(1, 105) = 17.688; p < 0.001], verbal aggression [F(1, 105) = 4.973; p = 0.028], anger [F(1, 105) = 7.662; p = 0.007], medicine ball throw [F(1, 105) = 36.143; p < 0.001], and YYIRT1 [F(1, 105) = 12.508; p = 0.001]. After-school small-sided volleyball for adolescents was accompanied by a significant decrease in aggression compared to physical education classes only. Additionally, adolescents from SSV group showed better results in physical fitness compared to the control group. Our findings significantly contribute to the understanding of possible mechanisms for reducing adolescents' aggression, which include enjoyment, motivation, and self-control through sport intervention.

Functional training added to intradialytic cycling lowers low-density lipoprotein cholesterol and improves dialysis adequacy: a randomized controlled trial.

BACKGROUND: Exercise has various positive effects on hemodialysis patients. However, there is no clear evidence which type of exercise yields better results. This study aimed to determine the effects of guided functional training added to the intradialytic cycling on dialysis adequacy and biochemical parameters in hemodialysis patients. Additionally, we aimed to investigate if patients could transfer functional exercise to an unsupervised home environment and retain gained improvements. METHODS: Randomization was done to a functional training intervention group (INT) (n = 20) or intradialytic cycling control group (CON) (n = 20). The INT attended a pre-dialysis functional training in the first 8 weeks. In the second 8 weeks, they performed functional exercises at unsupervised home environment on non-dialysis days. During the whole study, both groups participated in the intradialytic cycling program. RESULTS: Both groups demonstrated a significant increase in dialysis adequacy (Kt/V) in the eight (0.15, 95% CI 0.06 to 0.24; p = 0.003 for INT and 0.21, 95% CI 0.11 to 0.3; p < 0.001 for CON) and the 16th study week (0.13, 95% CI 0.03 to 0.24; p = 0.017 for INT and 0.13, 95% CI 0.03 to 0.22; p = 0.013 for CON) compared to their baseline values with no significant between-group differences. At week eight, the total cholesterol was significantly lowered in the INT (- 0.34 mmol/L, 95% CI - 0.6 to - 0.07; p = 0.016) and remained lower at week 16 (- 0.32 mmol/L, 95% CI - 0.64 to - 0.01; p = 0.049) with no significant changes in the CON. Low-density lipoprotein levels in the INT were significantly reduced after 8 weeks (- 0.35 mmol/L, 95% CI - 0.64 to - 0.06; p = 0.022) and remained reduced after 16 weeks (- 0.28 mmol/L, 95% CI - 0.52 to - 0.03; p = 0.030). There were no significant differences found for albumin, high-density lipoprotein cholesterol, triglycerides, C-reactive protein, and hemoglobin in both groups. CONCLUSIONS: We demonstrated that functional training added to intradialytic cycling improved lipid profile and dialysis adequacy. Additionally, the effects of the unsupervised, home-based program were preserved during the second study phase. This study supports the assumption that combined training is more effective compared to solely intradialytic exercise. TRIAL REGISTRATION: ClinicalTrials.Gov, NCT03334123 . Registered 07 November 2017.

Balance Tests in Pre-Adolescent Children: Retest Reliability, Construct Validity, and Relative Ability.

Balance is an essential prerequisite for the normal physical development of a child. It consists of the ability to maintain the body's centre of mass over its base of support, which is enabled by automatic postural adjustments, and maintain posture and stability in various conditions and activities. The present study aimed to determine the measurement characteristics (reliability and concurrent validity) and the relative ability of balance tests and different motor tests in healthy 11-year-olds. We also evaluated the impact of vision on balance ability. Our results showed high interrater reliability (from 0.810 to 0.910) and confirmed the construct validity of the included balance tests. Girls performed significantly better than boys in laboratory tandem stance in following balance components: total sway path with eyes open (BSEO) (t = 2.68, p = 0.01, effect size (ES) = 0.81), total body sway with eyes closed of centre of pressure (CoP) displacement in the a-p direction (BSEC) (t = 1.86, p = 0.07, ES = 0.57), mean velocity of CoP displacements (VEO) (t = 2.67, p = 0.01, ES = 0.83), mean amplitude of CoP displacements in the a-p direction (AapEO) (t = 3.38. p = 0.00, ES = 1.01) and in mean amplitude of CoP displacements in the m-l direction (AmlEO) (t = 3.68, p = 0.00, ES = 1.19). With eyes closed, girls performed significantly better (t = 2.28, p = 0.03, ES = 0.70) than boys did in the mean amplitude of COP displacements in the a-p direction (AapEO) and significantly better (t = 2.37, p = 0.03, ES = 0.71) in the mean amplitude of COP displacements in the m-l direction (AmlEC). Insignificant correlations between different balance tests, except for a correlation between the flamingo test and one-leg stance on a low beam (r = 0.558, p < 0.01), show that each test assesses different aspects of balance ability; therefore, balance cannot be assessed with a single test.

Author Correction: Kinesiologist-guided functional exercise in addition to intradialytic cycling program in end-stage kidney disease patients: a randomised controlled trial.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Validity, Reliability, and Usefulness of My Jump 2 App for Measuring Vertical Jump in Primary School Children.

There is a persistent need in sport science for developing a measuring tool that is affordable, portable, and easy to use. We aimed to examine the concurrent validity and test-retest reliability of the My Jump 2 app compared to a validated OptoJump instrument for measuring jump performance during the squat jump (SJ), countermovement jump (CMJ), and CMJ free arms (CMJAM) in primary school children. A total of 48 participants (11-14 years age), volunteered to participate in this research. The jumps were recorded with a validated OptoJump photoelectric cell system and a concurrent device (iPhone X through My Jump 2 app) at the same time. The participants repeated the testing procedure after two weeks to assess the reliability of the measurements (ICC). Systematic bias between sessions and tools was evaluated using the paired samples t-test and Bland and Altman analysis. High test-retest reliability (ICC > 0.89) was observed for all measures' in-between conditions. Very large correlations in the total sample were observed between the My Jump 2 app and OptoJump for SJ (r = 0.97, p = 0.001), CMJ (r = 0.97, p = 0.001), and CMJAM (r = 0.99, p = 0.001). Bland and Altman's plot depicting limits of agreement for the total sample between the OptoJump and My Jump 2 show that the majority of data points are within the 95% CIs. The results of this study suggest that My Jump 2 is a valid, reliable, and useful tool for measuring jump performance in primary school children.