The Effects of Heavy Resisted Sled Pulling on Sprint Mechanics and Spatiotemporal Parameters.

ABSTRACT: Stavridis, I, Ekizos, A, Zisi, M, Agilara, G-O, Tsolakis, C, Terzis, G, and Paradisis, G. The effects of heavy resisted sled pulling on sprint mechanics and spatiotemporal parameters. J Strength Cond Res 37(12): 2346-2353, 2023-This study examines the effects of 2 resisted sled sprinting (RSS) training programs: with a load corresponding to the running velocity associated with the apex of the individual velocity-power relationship (50%vdec), with a load equal to 10% of body mass (10% BM), and of an unresisted sprint training (URS). We measured the 30-m sprint performance in intervals of 5 m examining sprint acceleration, mechanical properties (theoretical maximal horizontal power [Pmax], force [F0], velocity [v0], slope of the force-velocity relationship [SFv], maximal ratio of horizontal-to-resultant force [RFmax], rate of decrease in RF [Drf]), and spatiotemporal parameters (step frequency [SF], step length [SL], flight time [FT], and contact time [CT]). Twenty-seven sprinters were randomly assigned into the 50%vdec, 10% BM, and URS groups, performing 12 sessions over 6 consecutive weeks (2 sets of 5 sprints per session). The 50%vdec group significantly improved (p < 0.05) their performance in all 30-m intervals. Posttraining, the 50%vdec group showed significantly increased Pmax, F0, and RFmax (mean differences: 1.46 ± 1.70 W·kg-1, 0.51 ± 0.68 N·kg-1, and 0.17 ± 0.18%, respectively), compared with pretraining. The 50%vdec group achieved higher SF, whereas FT decreased postintervention. No significant changes (p > 0.05) were found in the performance and mechanical and spatiotemporal variables in the other groups. In conclusion, RSS training with a load of 50%vdec provides an effective loading stimulus to induce adaptations that improve sprint acceleration performance. The improvements are explained by greater amounts of force and power, efficient force application, and higher step frequencies.

Exploring the predictors and prognostic significance of exercise-induced cardiac troponin release in master athletes following a 28 km mountain race. The Vamvakou research project.

BACKGROUND/OBJECTIVE: Aetiology and significance of exercise-induced troponin release remains a contentious issue. We investigated the effect of a 28 km mountain run on cardiac troponin I (cTnI), in relation to training, performance, nutritional, biochemical and echocardiography variables, in a group of 25 recreational male master athletes. MATERIAL AND METHODS: A comprehensive list of variables related with nutrition, training, performance and echocardiography, was collected pre- and post-race. Twenty-four months later, outcomes regarding cardiovascular events were obtained. RESULTS: Serum cTnI values were increased after the race, with mean values rising from 7.2 ± 2.2 (before) to 80.0 ± 33.2 ng/L (post race), (p < 0.001) and 23/25(92%) exceeding Upper Reference limit (50 ng/L). Echocardiography did not reveal significant alterations, or correlations with cTnI values. The percentage difference in hs-cTnI concentrations pre- and post-race correlated positively with age, race-induced changes of selected muscle damage indices, resistance training volume and negatively with endurance capacity and training volume (r: -0.727 to 0.725, p < 0.05). All athletes reported no cardiovascular event during the 24-month period post-race. CONCLUSION: cTnI elevation induced by a 28 km mountain running race was not correlated with echocardiographic, nutritional parameters and was less pronounced in athletes with larger endurance training history, in contrast with resistance training and age.

Mirror Cross-Exercise on a Kinetic Chain Approach Improves Throwing Performance in Professional Volleyball Athletes With Scapular Dyskinesis.

CONTEXT: Volleyball players have shown to be at an increased risk of developing scapular dyskinesis. The kinetic chain exercise approach has gained a lot of attention because of its claims to provide an improved motor control and scapular kinematics. A form of cross exercise, known as mirror therapy, may enhance the effects of a kinetic chain exercise approach in throwing performance. OBJECTIVE: To examine the effects of mirror cross exercise (MCE), based on a kinetic chain exercise approach in the throwing performance of volleyball athletes with scapular dyskinesis. DESIGN: Randomized controlled trial. SETTING: Biomechanics laboratory. METHODS: 39 volleyball players with scapular dyskinesis were randomly allocated into 3 groups. The first group completed a 6-week kinetic chain approach (KCA group), the second group completed a kinetic chain exercise approach program in addition to MCE group, and the control group followed only their regular training program. Before and after delivering both interventions, throwing accuracy, speed, and force were determined while measuring the ground reaction forces of the drive leg during throwing. Two-way mixed analysis of variance investigated the effects of intervention and time and their interaction. RESULTS: The results showed intervention × time statistically significant interactions for throwing accuracy, speed, and force for the MCE and the KCA groups. Over the 6-week training period, the MCE and the KCA groups showed significant improvements in throwing accuracy (P < .01) and speed (P < .01), while the ground reaction forces did not change (P > .05). Throwing force increased significantly in the MCE group (P = .01). Between-group comparison showed statistically significant improvements in the throwing accuracy for the MCE and KCA groups against the control group (P < .01) at posttesting. The MCE demonstrated superior results over the KCA in the aforementioned measures. CONCLUSIONS: This study suggests that the addition of MCE in a KCA program enhances energy transfer throughout the distal and proximal segments, thus improving kinetic chain recruitment and potentially preventing shoulder pathology.

Effect of a Supplementary Periodized Complex Strength Training and Tapering Period on Postactivation Potentiation of Sport-Specific Explosive Performance in Adolescent National-Level Fencers.

ABSTRACT: Kontochristopoulos, N, Bogdanis, GC, Paradisis, G, and Tsolakis, C. Effect of a supplementary periodized complex strength training and tapering period on postactivation potentiation of sport-specific explosive performance in adolescent national-level fencers. J Strength Cond Res 35(6): 1662-1670, 2021-This study examined the effects of strength training and tapering on countermovement jump (CMJ), change of direction (COD), and step-lunge (SL) after a conditioning activity in adolescent fencers. Twenty fencers (age: 15.8 ± 1.2 years) were randomly assigned to experimental (EXP, n = 10) group and control (CON, n = 10) group. EXP and CON groups performed 8 weeks of fencing training (4 times per week), while EXP group performed a supplementary strength training program twice per week, including a hypertrophy (first 2 weeks) and a complex strength training period (6 weeks). A 14-day tapering period with reduced training volume was then applied in both groups. Conditioning activity consisted of 3 × 3 seconds of maximal voluntary isometric contraction (MVIC; half-squat; knee angle = 90°), followed by either CMJ or COD or SL performance measurements in 3 different testing sessions 24 hours apart. There was no performance enhancement in all tests for both EXP and CON groups, after the conditioning MVIC before training (p > 0.05). After training, half-squat dynamic strength (1 repetition maximum [1RM]) was significantly increased only in the EXP group (from 74.8 ± 20.0 to 127.0 ± 28.9 kg, p = 0.001) and maintained after tapering. After tapering, baseline CMJ height was significantly increased only in the EXP group (from 27.2 ± 4.6 to 30.9 ± 3.8 cm, p = 0.003). Contrary to our hypothesis, the increase in 1RM and CMJ was not followed by a postactivation potentiation enhancement in all tests (p > 0.05), possibly because of the relatively low strength and jumping performance of fencers. Thus, adolescent high-level fencers do not exhibit a performance increase after MVIC, and this was not modified by the supplementary strength training protocol used.

Intermittent but Not Continuous Static Stretching Improves Subsequent Vertical Jump Performance in Flexibility-Trained Athletes.

Bogdanis, GC, Donti, O, Tsolakis, C, Smilios, I, and Bishop, DJ. Intermittent but not continuous static stretching improves subsequent vertical jump performance in flexibility-trained athletes. J Strength Cond Res 33(1): 203-210, 2019-This study examined changes in countermovement jump (CMJ) height after an intermittent or a continuous static stretching protocol of equal total duration. Sixteen male, elite-level gymnasts performed 90 seconds of intermittent (3 × 30 seconds with 30 seconds rest) or continuous stretching (90 seconds) of the quadriceps muscle. A single-leg stretching and jumping design was used, with the contralateral limb serving as a control. The same individuals performed both conditions with alternate legs in a randomized, counterbalanced order. One-leg CMJ height was measured for the stretched and the control leg after warm-up, immediately after stretching, and at regular intervals for 10 minutes after stretching. Range of motion (ROM) of the hip and knee joints was measured before, after, and 10 minutes poststretching. Compared with the control leg, intermittent stretching increased CMJ height by 8.1 ± 2.0%, 4 minutes into recovery (2.2 ± 2.0 cm, 95% confidence interval [CI]: 1.0-3.4 cm, p = 0.001), whereas continuous stretching decreased CMJ height by 17.5 ± 3.3% immediately after (-2.9 ± 1.7 cm, 95% CI: -2.0 to -3.7 cm, p = 0.001) and by 12.0 ± 2.7% 1 minute after stretching (-2.2 ± 2.1 cm, 95% CI: -1.2 to -3.2 cm, p = 0.001). The increases in hip (2.9 and 3.6°, p = 0.001. d = 2.4) and knee joint ROM (5.1 and 6.1°, p = 0.001. d = 0.85) after the intermittent and continuous stretching protocols were not different. The opposite effects of intermittent vs. continuous stretching on subsequent CMJ performance suggests that stretching mode is an important variable when examining the acute effects of static stretching on performance in flexibility-trained athletes.

Obesity and physical fitness indices of children aged 5-12 years living on remote and isolated islands.

INTRODUCTION: Obesity has become one of the major health risks in childhood, significantly affecting children's health and physical fitness. Although the marked increase of obesity in urban areas is well established, evidence is limited in remote and isolated areas with adverse socioeconomic features. The aim of this study was to examine the prevalence of obesity and its association with physical performance indices in young school-aged children living in 18 remote and isolated Greek islands. METHODS: Four hundred and sixty-three children (244 boys, 219 girls), aged 5-12 years underwent a series of physical fitness tests including 20 m sprint, standing long jump, 1 kg medicine ball throw, agility T-test and sit-and-reach test. Age and gender BMI cut-off points were determined according to World Health Organisation (WHO) norms. RESULTS: The prevalence of obesity was 23.8% and 13.2% for boys and girls, respectively. A negative body mass index (BMI) main effect was observed for weight-bearing activities, such as 20 m sprint (F=6.21, p=0.000, η2=0.041) and standing long jump (F=11.369, p=0.000, η2=0.074), while medicine ball throw was positively correlated with BMI in children aged 9-12 years. CONCLUSION: The results of this study confirmed previous findings on obesity prevalence in Greece. A negative association was also found between BMI and physical fitness indices and, in particular, in weight-bearing activities. It is critical to establish physical education interventions and physical fitness programs at schools, aiming to increase motivation for physical activity participation.

Acute Effects of Stretching on Leg and Vertical Stiffness During Treadmill Running.

Pappas, PT, Paradisis, GP, Exell, TA, Smirniotou, AS, Tsolakis, CK, and Arampatzis, A. Acute effects of stretching on leg and vertical stiffness during treadmill running. J Strength Cond Res 31(12): 3417-3424, 2017-The implementation of static (SS) and dynamic (DS) stretching during warm-up routines produces significant changes in biological and functional properties of the human musculoskeletal system. These properties could affect the leg and vertical stiffness characteristics that are considered important factors for the success of athletic activities. The aim of this study was to investigate the influence of SS and DS on selected kinematic variables, and leg and vertical stiffness during treadmill running. Fourteen men (age: 22.58 ± 1.05 years, height: 1.77 ± 0.05 m, body mass: 72.74 ± 10.04 kg) performed 30-second running bouts at 4.44 m·s, under 3 different stretching conditions (SS, DS, and no stretching). The total duration in each stretching condition was 6 minutes, and each of the 4 muscle groups was stretched for 40 seconds. Leg and vertical stiffness values were calculated using the "sine wave" method, with no significant differences in stiffness found between stretching conditions. After DS, vertical ground reaction force increased by 1.7% (p < 0.05), which resulted in significant (p < 0.05) increases in flight time (5.8%), step length (2.2%), and vertical displacement of the center of mass (4.5%) and a decrease in step rate (2.2%). Practical durations of SS and DS stretching did not influence leg or vertical stiffness during treadmill running. However, DS seems to result in a small increase in lower-limb force production which may influence running mechanics.

Variability of performance during a 60-min running race.

The aim of the present study was to examine the variability of 1-h running performance outside the laboratory, under conditions simulating those of a real competitive event. Twenty-three male recreational runners performed on 3 occasions a 60-min simulated running race attempting to cover as long distance as possible. The races took place in an indoor track, in order to ensure stable environmental conditions. There was no difference in the distance covered between races (12,546.3 ± 217 m, 12,576 ± 219.1 m, 12,638.7 ± 225.3 m for the 1st, 2nd and 3rd races, respectively (mean ± S(X), F(2, 44) = 1.168, P = 0.32). The coefficient of variation for all participants was 1.5 ± 0.2 (range: 0.2-3.00). Multiple regression analysis indicated that 83% of the variability in best performance was predicted by determining the speed at the peak volume of oxygen uptake and body mass. In conclusion, performance during 1-h simulated running race in an indoor track was highly reproducible. The present study can be used as low-cost, time-efficient and ecologically valid tool, which could test simultaneously numerous runners' performance under conditions similar to real competitive events.

Effects of muscle action type with equal impulse of conditioning activity on postactivation potentiation.

This study investigated the effects of muscle action type during conditioning activity (half-squat) on subsequent vertical jump performance. Fourteen track and field athletes (relative half-squat of 2.3 ± 0.3 times their body weight) completed 4 main trials in a randomized and counterbalanced order 5-7 days apart: (a) concentric (CON) half-squats: 7.5 ± 1.2 repetitions against 90% of 1 repetition maximum (1RM), (b) eccentric (ECC) half-squats: 9.3 ± 1.5 repetitions against 70% of 1RM, and (c) 3 sets of 3-second maximal isometric (ISO) half-squats, (d) a control (CTRL) trial, where subjects rested for 10 minutes. The number of repetitions in CON and ECC was adjusted so that the impulse of the vertical ground reaction force was similar to ISO. Countermovement vertical jump (CMJ) performance was evaluated for 21 minutes after each main trial. Countermovement vertical jump performance in ISO was higher than CTRL from the second to the 10th minute of recovery, whereas CMJ performance in ECC was higher than CTRL from the sixth and 10th minute of recovery. Analysis of the peak individual responses revealed an increase in CMJ performance compared with baseline only in ISO (3.0 ± 1.2%; p = 0.045), whereas no significant increases were observed in ECC and CON. Peak CMJ performance for all subjects in ISO and ECC was achieved within 2-10 minutes after the conditioning muscle actions. Isometric were more effective than CON and ECC muscle actions in increasing explosive leg performance when the impulse of the ground reaction force of the conditioning exercise was equated.

Reliabilities of leg and vertical stiffness during treadmill running.

The aim of this study was to determine the intra-participant variabilities (i.e. intra-day and inter-day reliabilities) in leg and vertical stiffness, as well as related kinematic parameters, during treadmill running using the sine-wave method. Twenty-two healthy men ran on a treadmill at 4.44 m/s, and the flight and contact times were measured with a high-speed video camera. Three 30-s running bouts with 2-min inter-bout rests were performed to examine the intra-day reliability, and single 30-s running bouts on three separate days with 24- to 48-h inter-bout intervals were performed to examine the inter-day reliability. The reliability statistics included repeated-measure analyses of variance, average inter-trial correlations, intra-class correlation coefficients (ICCs), Cronbach's α reliability coefficient, and the coefficient of variation. Both leg and vertical stiffness produced high ICCs within 0.972 and 0.982, respectively, and between 0.922 and 0.873 days, respectively. High values were also observed for all of the reliability coefficients. Similar results were found regarding contact time, flight time, step length, and step rate. It was concluded that the measurements of leg and vertical stiffness, as well as related kinematic parameters, obtained using the sine-wave method during treadmill running at 4.44 m/s, were highly reliable, both within and across days.

Effects of baseline levels of flexibility and vertical jump ability on performance following different volumes of static stretching and potentiating exercises in elite gymnasts.

This study examined the effects of baseline flexibility and vertical jump ability on straight leg raise range of motion (ROM) and counter-movement jump performance (CMJ) following different volumes of stretching and potentiating exercises. ROM and CMJ were measured after two different warm-up protocols involving static stretching and potentiating exercises. Three groups of elite athletes (10 male, 14 female artistic gymnasts and 10 female rhythmic gymnasts) varying greatly in ROM and CMJ, performed two warm-up routines. One warm-up included short (15 s) static stretching followed by 5 tuck jumps, while the other included long static stretching (30 s) followed by 3x5 tuck jumps. ROM and CMJ were measured before, during and for 12 min after the two warm-up routines. Three-way ANOVA showed large differences between the three groups in baseline ROM and CMJ performance. A type of warm-up x time interaction was found for both ROM (p = 0.031) and CMJ (p = 0.016). However, all athletes, irrespective of group, responded in a similar fashion to the different warm-up protocols for both ROM and CMJ, as indicated from the lack of significant interactions for group (condition x group, time x group or condition x time x group). In the short warm-up protocol, ROM was not affected by stretching, while in the long warm-up protocol ROM increased by 5.9% ± 0.7% (p = 0.001) after stretching. Similarly, CMJ remained unchanged after the short warm-up protocol, but increased by 4.6 ± 0.9% (p = 0.012) 4 min after the long warm- up protocol, despite the increased ROM. It is concluded that the initial levels of flexibility and CMJ performance do not alter the responses of elite gymnasts to warm-up protocols differing in stretching and potentiating exercise volumes. Furthermore, 3 sets of 5 tuck jumps result in a relatively large increase in CMJ performance despite an increase in flexibility in these highly-trained athletes. Key PointsThe initial levels of flexibility and vertical jump ability have no effect on straight leg raise range of motion (ROM) and counter-movement jump performance (CMJ) of elite gymnasts following warm-up protocols differing in stretching and potentiating exercise volumesStretching of the main leg muscle groups for only 15 s has no effect on ROM of elite gymnastsIn these highly-trained athletes, one set of 5 tuck jumps during warm-up is not adequate to increase CMJ performance, while 3 sets of 5 tuck jumps result in a relatively large increase in CMJ performance (by 4.6% above baseline), despite a 5.9% increase in flexibility due to the 30 s stretching exercises.

Excessive Knee Internal Rotation during Grand Plié in Classical Ballet Female Dancers.

Classical ballet dancers are exposed daily to physically demanding movements. Among these, the Grand Plié stands out for its biomechanical complexity, particularly the stress applied to the knee joint. This study investigates the knee kinematics of healthy professional classical ballet dancers performing the Grand Plié. Twenty dancers were evaluated with a motion analysis system using a marker-based protocol. Before measurements, the self-reported Global Knee Functional Assessment Scale was delivered for the knees' functional ability, and the passive range of knee motion was also assessed. The average score on the Global Knee Functional Assessment Scale was 94.65 ± 5.92. During a complete circle of the Grand Plié movement, executed from the upright position, the average maximum internal rotation of the knee joint was 30.28° ± 6.16°, with a simultaneous knee flexion of 134.98° ± 4.62°. This internal rotation observed during knee flexion exceeds the typical range of motion for the joint, suggesting a potential risk for knee injuries, such as meniscal tears. The findings provide an opportunity for future kinematic analysis research, focusing on the movement of the Grand Plié and other common ballet maneuvers. These data have the potential to yield valuable information about the knee kinematics concerning meniscus damage.

The effect of gender, age and sports specialisation on isometric trunk strength in Greek high level young athletes.

Aim of the study was to compare the isometric strength of flexors and extensors trunk muscles between male and female elite adolescent athletes of different age and training experience. Absolute and relative trunk muscle isometric peak extension (PTE) and flexion (PTF) torque, as well as flexion/extension (F/E) ratio were evaluated in 388 elite adolescent athletes 188 males (Age: 15.4±1.8 years, Body height: 175.5±11.2 cm, Body mass: 68.8±14.5 kg, BMI: 22.1±0.3 kg/m2) and 207 females (Age: 15.1±1.6 years, Body height: 166.8±7.8 cm, Body mass: 60.8±8.4 kg and BMI: 21.8±0.4 kg/m2). Participants were assigned into seven different groups according to their sport specialisation (oars-paddle, swimming, contact-combat, team, racket, winter and mixed other sports). Significant effect of age (η2: 0.077-0.112, p < 0.05), gender (η2: 0.020-0.077; p < 0.05) and sport category factors (η2: 0.057-0.154. p < 0.005) for absolute/relative PTE, PTF and F/E ratio was found. The highest values were observed in contact-combat and the lowest in mixed other sports groups. F/E ratio significantly differs between the age groups, especially in female athletes. The present data suggest that TMSs and F/E ratio are highly affected by age, gender and sports specialisation in high level trained adolescents.

Unraveling the "golden ratio": a pilot study investigating acute-to-chronic workload ratio in breast cancer patients undergoing active treatment.

Training load monitoring is a common practice in sports medicine for supporting athletes' health and performance. Despite progress in exercise oncology research for breast cancer patients, training load monitoring is underutilized. This study retrospectively investigated the relationship between maintained training load within a defined range and physical and health outcomes of ten breast cancer patients during active anticancer treatment who underwent a 12-week exercise program. Intervention consisted of endurance and resistance training, three times a week, with each session lasting 30-45 min. Assessments were conducted at baseline, 6 and 12 weeks after enrollment, evaluating physical function (6-min walk test-6MWT, and sit-to-stand), muscle strength, body composition, sleep quality (Pittsburgh Sleep Quality Index-Pittsburgh Sleep Quality Index), quality of life (EORTC-QLQ-C30), heart rate variability and physical activity levels (International Physical Activity Questionnaire-International Physical Activity Questionnaire). The Physiological Cost Index/Energy Expenditure Index (PCI/EEI) was estimated using the 6MWT and Heart rate. Training load monitoring was performed by session rating of perceived exertion (sRPE, relative intensity multiplying with session duration). Acute-to-Chronic Workload Ratio (ACWR) (7:28, rolling average) was calculated accordingly. Analyses were performed within-subjects across time points and between-subjects, comparing those who maintained from weeks 6-12 an ACWR of 0.8-1.3 with those who did not. Adherence rates were similar between groups. Physical function improved in the total sample with large effect sizes (Δ6MWT = 56.5 m [95%CI: 6-100 m], effect size [w] = 0.52, p = 0.006; ΔSit-to-Stand = 1.5 [95%CI: 1-5], effect size [w] = 0.681, p < 0.001), demonstrating greater changes in patients with higher ACWR. Sleep quality improvements were higher in the appropriate ACWR group (p = 0.016). A positive correlation was demonstrated between global health status and 6MWT change from baseline to 12 weeks (ρ = 0.689, p = 0.04). Despite a small sample size, patients maintaining sufficient relative training load presented greater physical fitness and sleep quality improvements. Thus, training load monitoring may enhance exercise program benefits in breast cancer patients under active treatment.

Effect of a home-based exercise training program on anthropometric characteristics and exercise performance during Covid-19 quarantine in young high-level kayak athletes.

Purpose: The Covid-19 restriction exposed most athletes to insufficient training stimuli leading to detraining. This study investigated whether a home-based exercise training program could preserve body composition and exercise performance in young high-level kayak athletes during Covid-19 restriction. Methods: Seventeen healthy young high-level kayak athletes (10 males and 7 females), aged 14.7 ± 1 yrs, participated in this study. A 7-week home-based training program was followed during Covid-19 restriction. Baseline measurements were assessed 4 weeks before Covid-19 pandemic and ended on 4 May 2020. Body composition, flexibility, isometric muscle trunk strength (Biodex), anaerobic power (30-s all-out trial), and aerobic capacity (4-min maximal test) were evaluated. Personal daily loads and wellness details were collected with AthleteMonitoring.com software. Results: Home-based exercise training program was effective to improve flexibility (9.20 ± 2.85%) and lean body mass (3.96 ± 0.89%), to maintain muscle strength, anaerobic power, body mass, and body fat percentage but insufficient to maintain aerobic capacity (- 8.96 ± 2.49%). Conclusion: The findings of the present study potentially highlight the importance of the implementation of such a program to minimize the detraining effect on young athletes during periods of movement restriction caused by pandemics.

Delayed Effect of Dry-Land Strength Training Sessions on Swimming Performance.

The purpose of the study was to examine the effects of dry-land strength endurance (SE) and maximum strength (MS) sessions on next-day swimming performance. Eight swimmers (age: 18.6 ± 2.9 years) performed evening training sessions (19:00-19:40), including: (i) SE (2 × 15 - 20 repetitions, 50% of 1-RM), (ii) MS (2 × 5 repetitions, 90% of 1-RM), (iii) control (CON: no dry-land training). All sessions were followed by a 90-min swimming training (20:00-21:30). Medicine ball throw and countermovement jump, free countermovement jump and squat jump were evaluated before and after the dry-land training session and 12 h later, before a 100-m front crawl sprint (next day at 8:30 a.m.). Performance time, RPE, blood lactate and biomechanical variables in 100-m sprint were no different between conditions (time, MS: 64.70 ± 7.35, SE: 63.81 ± 7.29, CON: 64.52 ± 7.71 s, p > 0.05). Jump height was not changed before and after dry-land and before the 100-m sprint in all conditions (p > 0.05). Medicine ball throw was lower in MS compared to CON before the 100-m sprint (MS: 4.44 ± 1.11, vs. CON: 4.66 ± 1.21 m, p < 0.05). Upper-body but not lower- body muscle function may be affected by MS training. However, performance in a 100-m test is not affected by dry-land training performed 12 h earlier.

Preliminary Insights into the Diagnostic Accuracy of the Modified Arm Care Screen Test for Overhead Athletes: An On-Field Tool for Injury Prevention.

BACKGROUND: The Arm Care Screen was developed to detect musculoskeletal limitations that could affect performance or even increase the risk for shoulder injuries in overhead athletes. This study aimed to assess the discriminant validity of the modified Arm Care Screen in overhead athletes. METHODS: Sixty-two overhead athletes (mean age: 24.5 ± 4.2 years) were recruited. The athletes underwent a comprehensive Arm Care Screen evaluation, including reciprocal shoulder mobility, total body rotation, lower body diagonal reach, and rotary stability assessments. Ten different musculoskeletal measurements were independently measured by two physical therapists. RESULTS: The modified Arm Care Screen showed moderate to strong associations (phi values ranged from 0.273 to 0.905) with the respective musculoskeletal range of motion and balance measurements. Sensitivity ranged from 81.25% to 88.57%, indicating a high true positive rate, and specificity ranged from 43.75% to 94.44%, indicating a moderate to strong positive rate. Positive and negative likelihood ratios ranged from 1.48 to 15.92 and 0.12 to 0.38, respectively. The positive and negative predictive value ranged from 58.14% to 92% and from 73.68% to 93.18%, respectively. The accuracy of the modified ACS ranged from 62.90% to 91.94%. CONCLUSION: The modified Arm Care Screen demonstrated promising diagnostic accuracy in identifying significant movement restrictions.

The Acute and Chronic Effects of Resistance and Aerobic Exercise in Hemostatic Balance: A Brief Review.

Hemostatic balance refers to the dynamic balance between blood clot formation (coagulation), blood clot dissolution (fibrinolysis), anticoagulation, and innate immunity. Although regular habitual exercise may lower the incidence of cardiovascular diseases (CVD) by improving an individual's hemostatic profile at rest and during exertion, vigorous exercise may increase the risk of sudden cardiac death and venous thromboembolism (VTE). This literature review aims to investigate the hemostatic system's acute and chronic adaptive responses to different types of exercise in healthy and patient populations. Compared to athletes, sedentary healthy individuals demonstrate similar post-exercise responses in platelet function and coagulatory and fibrinolytic potential. However, hemostatic adaptations of patients with chronic diseases in regular training is a promising field. Despite the increased risk of thrombotic events during an acute bout of vigorous exercise, regular exposure to high-intensity exercise might desensitize exercise-induced platelet aggregation, moderate coagulatory parameters, and up-regulate fibrinolytic potential via increasing tissue plasminogen activator (tPA) and decreasing plasminogen activator inhibitor (PAI-1) response. Future research might focus on combining different types of exercise, manipulating each training characteristic (frequency, intensity, time, and volume), or investigating the minimal exercise dosage required to maintain hemostatic balance, especially in patients with various health conditions.

Pre- and Postoperative Exercise Effectiveness in Mobility, Hemostatic Balance, and Prognostic Biomarkers in Hip Fracture Patients: A Study Protocol for a Randomized Controlled Trial.

Hip fractures are a major health concern, particularly for older adults, as they can reduce life quality, mobility loss, and even death. Current evidence reveals that early intervention is recommended for endurance in patients with hip fractures. To our knowledge, preoperative exercise intervention in patients with hip fractures remains poorly researched, and no study has yet applied aerobic exercise preoperatively. This study aims to investigate the short-term benefits of a supervised preoperative aerobic moderate-intensity interval training (MIIT) program and the added effect of an 8-week postoperative MIIT aerobic exercise program with a portable upper extremity cycle ergometer. The work-to-recovery ratio will be 1-to-1, consisting of 120 s for each bout and four and eight rounds for the pre- and postoperative programs, respectively. The preoperative program will be delivered twice a day. A parallel group, single-blinded, randomized controlled trial (RCT) was planned to be conducted with 58 patients each in the intervention and control groups. This study has two primary purposes. First, to study the effect of a preoperative aerobic exercise program with a portable upper extremity cycle ergometer on immediate postoperative mobility. Second, to investigate the additional effect of an 8-week postoperative aerobic exercise program with a portable upper extremity cycle ergometer on the walking distance at eight weeks after surgery. This study also has several secondary objectives, such as ameliorating surgical and keeping hemostatic balance throughout exercise. This study may expand our knowledge of preoperative exercise effectiveness in hip fracture patients and enhance the current literature about early intervention benefits.

Lumbar Kinematics Assessment of Patients with Chronic Low Back Pain in Three Bridge Tests Using Miniaturized Sensors.

Lumbar muscle atrophy, diminished strength, stamina, and increased fatigability have been associated with chronic nonspecific low back pain (LBP). When evaluating patients with LBP, trunk or core stability, provided by the performance and coordination of trunk muscles, appears to be essential. Several clinical tests have been developed to identify deficiencies in trunk performance, demonstrating high levels of validity and reproducibility. The most frequently prescribed tests for assessing the core body muscles are the prone plank bridge test (PBT), the side bridge test (SBT), and the supine bridge test (SUBT). However, quantitative assessments of the kinematics of the lumbar spine during their execution have not yet been conducted. The purpose of our study was to provide objective biomechanical data for the assessment of LBP patients. The lumbar spine ranges of motion of 22 healthy subjects (Group A) and 25 patients diagnosed with chronic LBP (Group B) were measured using two inertial measurement units during the execution of the PBT, SUBT, and SBT. Statistically significant differences between the two groups were found in all three tests' kinematic patterns. This quantitative assessment of lumbar spine motion transforms the three bridge tests into an objective biomechanical diagnostic tool for LPBs that may be used to assess the efficacy of applied rehabilitation programs.