Influence of Substitutions and Roles on Kinematic Variables in Professional Soccer Players.

In soccer, roles and substitutions can make it unclear how different physical capacities decrease over time and impact performance. This investigation aimed to analyze kinematic parameters and their changes over game time, and provide information to effectively prescribe training programs. Data from four professional teams were analyzed, and all the teams competed in the Italian First Division (Serie A). Average metabolic power and high-intensity activities associated with critical moments in the match were considered in the comparisons. The video analysis system STATS SportVU collected the data during official matches. Players were assigned to a specific group according to their time played, categorized as follows: 0-15', 15-30', 30-45', 45-60', 60-75', 75-90', and > 90 min. Different roles, including forwards and wingers (FW), midfielders (MF), center-backs (CB), and side-backs (SB) were also considered. Significant differences (p<0.05) were found in different roles and within roles at different times played. The results highlighted how MF performance decreased over time, whereas CB was unaffected by time. SB spent more time at very high velocity than other roles, independently from the time played. These findings provide valuable information about the physical demands of official soccer matches and could be used to review training prescriptions.

Exercise to Counteract Alzheimer's Disease: What Do Fluid Biomarkers Say?

Neurodegenerative diseases (NDs) represent an unsolved problem to date with an ever-increasing population incidence. Particularly, Alzheimer's disease (AD) is the most widespread ND characterized by an accumulation of amyloid aggregates of beta-amyloid (Aß) and Tau proteins that lead to neuronal death and subsequent cognitive decline. Although neuroimaging techniques are needed to diagnose AD, the investigation of biomarkers within body fluids could provide important information on neurodegeneration. Indeed, as there is no definitive solution for AD, the monitoring of these biomarkers is of strategic importance as they are useful for both diagnosing AD and assessing the progression of the neurodegenerative state. In this context, exercise is known to be an effective non-pharmacological management strategy for AD that can counteract cognitive decline and neurodegeneration. However, investigation of the concentration of fluid biomarkers in AD patients undergoing exercise protocols has led to unclear and often conflicting results, suggesting the need to clarify the role of exercise in modulating fluid biomarkers in AD. Therefore, this critical literature review aims to gather evidence on the main fluid biomarkers of AD and the modulatory effects of exercise to clarify the efficacy and usefulness of this non-pharmacological strategy in counteracting neurodegeneration in AD.

Whole Body Vibration Improves Brain and Musculoskeletal Health by Modulating the Expression of Tissue-Specific Markers: FNDC5 as a Key Regulator of Vibration Adaptations.

Whole body vibration (WBV) is well known to exert beneficial effects on multiple tissues, improving synaptic transmission, muscle mass, bone quality, and reducing anxiety and depressive behavior. However, the underlying molecular mechanisms are not yet fully understood, and organs and tissues may respond differently to the vibratory stimulus depending on multiple factors. Therefore, we investigated the WBV effects on the brain and musculoskeletal tissue of 4-month-old young mice, evaluating synaptic plasticity by electrophysiological recordings and tissue organization by histology and histomorphometric analysis. Specifically, WBV protocols were characterized by the same vibration frequency (45 Hz), but different in vibration exposure time (five series of 3 min for the B protocol and three series of 2 min and 30 s for the C protocol) and recovery time between two vibration sessions (1 min for the B protocol and 2 min and 30 s for the C protocol). In addition, immunohistochemistry was conducted to evaluate the expression of fibronectin type III domain-containing protein 5 (FNDC5), as well as that of tissue-specific markers, such as brain-derived neurotrophic factor (BDNF) in brain, myostatin in muscle and collagen I (COL-1) in bone. Our results suggest that the WBV effects depend closely on the type of protocol used and support the hypothesis that different organs or tissues have different susceptibility to vibration. Further studies will be needed to deepen our knowledge of physiological adaptations to vibration and develop customized WBV protocols to improve and preserve cognitive and motor functions.

Relationship between aerobic fitness and metabolic power metrics in elite male soccer players.

The aim was to assess the relationship between aerobic fitness and metabolic power metrics in elite male soccer players, and the possible differences that playing positions might impose during match play over new metabolic power metrics. Sixty-two elite professional male soccer players (13 central backs, 13 side backs, 22 midfielders, and 14 forwards) took part in the study. Players were monitored during eleven months of full training (including pre-season and in-season) and over all official matches (Serie A matches, Italy Cup matches). Aerobic fitness tests were conducted one week after the start of the preseason, and 8, 24 and 36 weeks after the beginning of the Championship. Players' aerobic fitness and metabolic power metrics were considered as the mean of all seasonal testing and of pooling data of 38 championship matches and 3 or 6 Italy Cup matches for all the calculations respectively. The velocity at 4 mmol·L-1 (VL4) was significantly related to metabolic power metrics match variables with correlation ranging from trivial to very large (r = 0.32 to r = 0.89). Receiver-operating-characteristic (ROC) analysis showed that speed at VL4 was sensitive in detecting high metabolic power distance (HMPD) changes in all but central back players as revealed by area under the curve (central back .78, 95%CI .47 to .95; full back .93, 95%CI .64 to 0.99; midfielder .88, 95%CI .67 to 0.98; forward .90, 95%CI .62 to 0.99). This study's findings provide further evidence for the ecological validity of aerobic fitness in elite male soccer players. Players having a HMPD cut-off equal to or higher than > 1450 m for central backs, > 1990 m for full backs, > 2170 m for midfielders and > 1670 m for forwards may be considered as possessing superior aerobic fitness status. In light of this study's findings, the VL4 test may be considered a valid test to evaluate meaningful information for direct generic aerobic training in soccer players.

The effect of age, sex and a firm-textured surface on postural control.

In previous studies, the influence of plantar sensation has been examined using various textured surfaces with different stiffness materials to assess static balance. This study investigated the effects of a Firm Textured Surface (FTS) along with age and sex-related influences on postural control under different visual conditions. Forty subjects (20 elderly, 10 males, mean age 68.30, 10 females, mean age 68.00, and 20 young people, 10 males, mean age 25.45, 10 females, mean age 27.30) participated in this study maintained a quiet standing on FTS, foam and firm surfaces with eyes open and closed. The center of pressure displacement (CoPDISP), CoP velocity (CoPVEL), and sway velocity of the CoP in anteroposterior (AP) and mediolateral (ML) direction (VA/P and VM/L) were measured. FTS was associated with lower postural sway measures in both the groups with eyes open and closed. However, the foam surface showed the worst results in all postural parameters under all experimental conditions. Separate four-way ANOVAs were applied to each dependent variable. The main effects of surface (p < 0.0001), vision (p < 0.0001) and age (p < 0.0001 for CoPDISP, CoPVEL and VA/P; p = 0.0003 for VM/L) were significant in each of the four fitted models. Sex was never significant, either as a main effect or an interaction with other experimental factors. Eyes open were able to reduce the negative effects of the foam surfaces but without vision the proprioceptive sensory system cues of the body state become more important for maintaining balance. A good stimulation with rigid texture should be considered as relief to reduce the physiological-related decline of afferent information with age.

Electric field modulation of magnetic exchange in molecular helices.

The possibility to operate on magnetic materials through the application of electric rather than magnetic fields-promising faster, more compact and energy efficient circuits-continues to spur the investigation of magnetoelectric effects. Symmetry considerations, in particular the lack of an inversion centre, characterize the magnetoelectric effect. In addition, spin-orbit coupling is generally considered necessary to make a spin system sensitive to a charge distribution. However, a magnetoelectric effect not relying on spin-orbit coupling is appealing for spin-based quantum technologies. Here, we report the detection of a magnetoelectric effect that we attribute to an electric field modulation of the magnetic exchange interaction without atomic displacement. The effect is visible in electron paramagnetic resonance absorption of molecular helices under electric field modulation and confirmed by specific symmetry properties and spectral simulation.

A Pilot Study on the e-Kayak System: A Wireless DAQ Suited for Performance Analysis in Flatwater Sprint Kayaks.

Nowadays, in modern elite sport, the identification of the best training strategies which are useful in obtaining improvements during competitions requires an accurate measure of the physiologic and biomechanical parameters that affect performance. The goal of this pilot study was to investigate the capabilities of the e-Kayak system, a multichannel digital acquisition system specifically tailored for flatwater sprint kayaking application. e-Kayak allows the synchronous measure of all the parameters involved in kayak propulsion, both dynamic (including forces acting on the paddle and footrest) and kinematic (including stroke frequency, displacement, velocity, acceleration, roll, yaw, and pitch of the boat). After a detailed description of the system, we investigate its capability in supporting coaches to evaluate the performance of elite athletes' trough-specific measurements. This approach allows for a better understanding of the paddler's motion and the relevant effects on kayak behavior. The system allows the coach to carry out a wide study of kayak propulsion highlighting, and, at the same time, the occurrences of specific technical flaws in the paddling technique. In order to evaluate the correctness of the measurement results acquired in this pilot study, these results were compared with others which are available in the literature and which were obtained from subjects with similar characteristics.

Effectiveness of Warm-Up Routine on the Ankle Injuries Prevention in Young Female Basketball Players: A Randomized Controlled Trial.

Background and Objectives: Ankle joint is the most common site of injury for basketball athletes. An effective warm-up (WU) is a period of preparatory exercise to improve training performance and reduce sports injuries. Continuous examination of effective WU routines in basketball players is a necessity. The aim of this study was to investigate the effects of general and combined warm up on ankle injury range of motion (ROM) and balance in young female basketball players. Materials and Methods: A sample of 28 young female basketball players were randomly allocated to either global warm up control group (GWU) (n = 11) or combined warm up experimental group (CWU) (n = 17). All participants performed 7-min of run. The CWU group performed a single leg stance barefoot with eyes closed, plank forearm position and triceps sural stretching. Participants in GWU performed walking ball handling and core stability using a Swiss ball. Both WU routines were conducted 3 times per week for 10 weeks. Outcome measurements were the Stabilometric platform and dorsiflexion lunge test. Results: Twenty-eight young female basketball players completed the study. Participants in the experimental group improved significantly in the range of motion (ROM) in right and left ankle and the center of pressure displacement (CoP). The control group did not show any changes in ankle dorsiflexion and a significant reduction in all body balance parameters. Conclusions: An 8-min combined warm-up routine for 10 weeks improves the ankle dorsiflexion ROM and CoP displacement that plays a key role in ankle injuries prevention in basketball players. Further studies are strongly needed to verify our findings.

Effects of stimulating surface during static upright posture in the elderly.

This study aimed to investigate the influence of three stimulating surfaces based on center of pressure (CoP), anteroposterior sway velocity (V(A/P)), and medio-lateral sway velocity (V(M/L)) of 40 elderly subjects. CoP and V(M/L) showed a significant decrease in all visual conditions only in the stimulating surface whereas V(A/P) showed a significant decrease only on the same surface with eyes open. Results confirm the importance of multisensory stimulation in postural control in the elderly.

The efficacy of plantar stimulation on human balance control.

AIM: The aim of this study was to evaluate the body sway using firm, foam, and firm textured surfaces on 17 young adults. METHOD: Displacement of center of pressure (CoP), anteroposterior velocity (VA/P), and mediolateral velocity (VM/L) were measured. DATA: The data showed a significant decrease of CoP, VA/P, and VM/L between support surfaces and vision. RESULTS: The results showed that, differently from the firm and foam, the textured surface is able to increase the plantar feedback to maintaining postural control.

Morning meal more efficient for fat loss in a 3-month lifestyle intervention.

OBJECTIVE: To evaluate the effects of 2 low-calorie diets but with different distributions of calories throughout the day on weight loss and other major obesity-related metabolic parameters. METHODS: We randomly assigned 42 nonsmoking homemakers (age = 46.3 ± 2.3 years, body mass index [BMI] = 35.7 ± 0.8 kg/m(2), mean ± SD) in 2 groups of 21 subjects (G1 and G2). The participants underwent a 3 month individualized Mediterranean-style diet (55% carbohydrate, 30% fat, 15% protein and fiber > 30 g), calorie (600 kcal daily deficit compared to the total energy expenditure measured by a metabolic Holter). Diets consisted of the same food and complied with cardiovascular disease prevention guidelines but differed in the distribution of calories throughout the day (G1: 70% breakfast, morning snack, lunch and 30% afternoon snack and dinner; G2: 55 breakfast, morning snack, lunch and 45% afternoon snack and dinner). Dual-energy X-ray absorptiometry was used for pre- and postintervention body composition assessment. RESULTS: Thirty-six subjects completed the study (G1 = 18, G2 = 18). Both groups had significant improvements in body composition and metabolic parameters but G1 had enhanced results for weight loss (G1: -8.2 ± 3.0 kg; G2: -6.5 ± 3.4 kg; p = 0.028), waist circumference reduction (G1: -7 ± 0.6 cm; G2: -5 ± 0.3 cm; p = 0.033), and fat mass loss (G1: -6.8 ± 2.1 kg, G2: -4.5 ± 2.9 kg, p = 0.031; mean ± SD). Improvements were detected in both groups for blood pressure and blood and lipid parameters. G1 subjects showed a greater improvement in insulin sensitivity measured by homeostasis model assessment-estimated insulin resistance (G1: -1.37 ± 0.27, G2: -0.74 ± 0.12, p = 0.017). CONCLUSIONS: These data suggest that a low-calorie Mediterranean diet with a higher amount of calories in the first part of the day could establish a greater reduction in fat mass and improved insulin sensitivity than a typical daily diet.

Acute effects of whole-body vibration on running gait in marathon runners.

The aim of this study was to investigate the effects of a single bout of whole-body vibration (WBV) on running gait. The running kinematic of sixteen male marathon runners was assessed on a treadmill at iso-efficiency speed after 10 min of WBV and SHAM (i.e. no WBV) conditions. A high-speed camera (210 Hz) was used for the video analysis and heart rate (HR) was also monitored. The following parameters were investigated: step length (SL), flight time (FT), step frequency (SF), contact time (CT), HR and the internal work (WINT). Full-within one-way analysis of variance (ANOVA) of the randomised crossover design indicated that when compared to SHAM conditions, WBV decreased the SL and the FT by ~4% (P < 0.0001) and ~7.2% (P < 0.001), respectively, and increased the SF ~4% (P < 0.0001) while the CT was not changed. This effect occurred during the first minute of running: the SL decreased ~3.5% (P < 0.001) and SF increased ~3.3% (P < 0.001). During the second minute the SL decreased ~1.2% (P = 0.017) and the SF increased ~1.1% (P = 0.02). From the third minute onwards, there was a return to the pre-vibration condition. The WINT was increased by ~4% (P < 0.0001) during the WBV condition. Ten minutes of WBV produced a significant alteration of the running kinematics during the first minutes post exposure. These results provide insights on the effects of WBV on the central components controlling muscle function.

Return to training in soccer players after anterior cruciate ligament reconstruction: reflections and considerations.

This clinical and rehabilitative overview focuses on the return to unrestricted sporting activity, aiming to consolidate the scientific evidence surrounding the structural progression of athletes, particularly footballers, undergoing anterior cruciate ligament reconstruction (ACLR). A multidisciplinary approach necessitates a shared language and standardized methodologies. Unfortunately, significant disparities persist in the structural strategies guiding the decision-making process for returning to on-field activities, the latter stages of rehabilitation, and subsequent restoration of technical and tactical football abilities. Divergences in definitions, terminologies, and rehabilitation protocols can substantially influence final outcomes. Presently, scientific consensus studies regarding the decision-making process during the final stages of on-field rehabilitation are lacking. Nevertheless, this overview outlines and defines pivotal language parameters crucial for effective communication and the seamless integration of clinical and rehabilitative data among the diverse professionals involved in facilitating the athlete's return to peak performance. In conclusion, the successful resumption of competitive sporting activities for footballer's post ACLR demands a collaborative decision-making approach encompassing various professionals. Additionally, it necessitates a cohesive transition from rehabilitation to on-field work, aiming at reinstating athleticism, technical prowess, and tactical acumen.

Dose-response effects of physical exercise standardized volume on peripheral biomarkers, clinical response, and brain connectivity in Parkinson's disease: a prospective, observational, cohort study.

Background: Exercise has been proposed as the "Universal Prescription for Parkinson's Disease"; however, the specificity of exercise dose in terms of frequency, intensity, duration, and type to be prescribed remains to be elucidated. The 2018 US updated guidelines and WHO Guidelines on Physical Activity and Sedentary Behavior recommend older adults (> 65+ years) to achieve weekly minimal activity levels, indicating the intensity of aerobic exercise as the metabolic equivalent of task and duration as minutes/week (150-300 min/week at a moderate intensity of 3-5.9 MET- or 75-150 min/week of a vigorous intensity of ≥6 MET). Translating these recommendations to PD patients, the study aimed to assess the dose-response effects of standardized volume of structured exercise, measured as METs-minutes/week (weekly energy expenditure) of two different rehabilitation settings to quantify the change in neurotrophic factors. The exercise-induced benefits between the two rehabilitation settings will be evaluated based on motor and non-motor symptoms, kinematic parameters of gait, cognitive function, quality of life, and cortical activity and brain connectivity. Methods: METEX-PD is a pilot, prospective, observational, cohort study. The study will enroll consecutively thirty (N = 30) participants with mild-to-moderate Parkinson's disease diagnosis to be assigned to a non-intensive or intensive rehabilitation group. The non-intensive rehabilitation group will achieve a range of 180-270 METs-min/week (90 min/week of low-intensity aerobic exercise, 2-3 METs), while the intensive rehabilitation group will exercise at 1350-1980 METs-min/week (225 min/week of high-intensity aerobic exercise, 6-8.8 METs). The METEX-PD trial will last 12 weeks, including 4 weeks of aerobic training program and two follow-ups. Assessments will be performed at baseline (T0), at the end of the exercise program (T1-end of the program), and 4- and 8 weeks after the end of the training program (FU-1 and FU-2). The primary outcome is the change from baseline in peripheral blood BDNF levels. Secondary outcomes are differences in peripheral biomarkers, functional-motor assessments, clinical-functional evaluations, and brain imaging. Conclusion: METEX-PD trial will enable us to estimate the change in BDNF levels and other peripheral biomarkers under precise exercise-induced energy expenditure. The primary results of the METEX-PD study will allow the development of a larger multicenter randomized controlled trial to investigate the molecular pathways inducing the change in selected neurotrophic factors, such as BDNF, IGF-1, or irisin, and the downstream mechanisms of neuroplasticity in PD patients.

Footstep analysis at different slopes and speeds in elite race walking.

In order to investigate the effects of speed and slope on kinematic parameters, we studied the step parameters of 12 elite race walkers on a treadmill at different speeds (3.61, 3.89, and 4.17 m·s(-1)) and slopes (0, 2, and 7%). A high-speed digital camera (210 Hz) was used to record motion, and 2D data were analyzed with Dartfish 5.5Pro. The parameters studied were step length (SL), step frequency (SF), and contact time (CT). The results showed that the increases in SL were linearly related to increases in speed: r = 0.37 with p < 0.01, whereas decreases in SL were elicited with an increase in slope r = -0.56, p < 0.0001 ([0-2% = -3.5%, p < 0.02], [0-7% = -7.5%, p < 0.01]). The SF was positively correlated with increases in speed, r = 0.56, p = 0.0001, and slopes, r = 0.50, p < 0.0001 (0-2% = 3.6% n.s.; 0-7% = 8.5%, p < 0.01). Conversely, CT was negatively correlated with increases of both speed; r = -0.57, p < 0.0001 and slope r = -0.50, p < 0.0001 (0-2% = -3.4%, n.s.; 0-7% = -7.7%, p < 0.01). These results suggest that using slopes <7% could considerably alter the neuromechanical behavior of athletes, whereas slopes around 2% could positively influence the performance of the elite race walkers without altering the race-walking technique.

Uphill racewalking at iso-efficiency speed.

The aim of this study was to investigate the effects of gradients (0, 2, and 7%) on biomechanical parameters during racewalking (RW) at iso-efficiency speed (IES). During the experiment, 12 high-level athletes performed at IES on different slopes. The parameters studied were surface muscular activity (EMG) of 5 muscles of the leg using Muscle Lab (Boscosystem); kinematic parameters were collected using a high-speed camera (210 Hz) analyzed with Dartfish 5.5 Pro; and heart rate (HR) was monitored with a Cardio Polar. The results showed step length (SL), step frequency (SF), and internal work (WINT) decreased with increased treadmill gradient: SL = ([0-2% = 3.48%, p = 0.158], [0-7% = 12.17%, p < 0.001]); SF = ([0-2% = 2.38%, p = 0.173], [0-7% = 6.07%, p < 0.01]); WINT = ([0-2% = 8.34%, p < 0.001], [0-7% = 22.81%, p < 0.0001]). Conversely, contact time (CT) and HR increased less significantly with the increased gradients: CT = ([0-2% = 2.46%, p = 0.198], [0-7% = 6.56%, p < 0.01]); HR = ([0-2% = 0.62%, p = 0.652], [0-7% = 3.25%, p < 0.05]). The knee angle (KE) increased, whereas ankle angle (AK) and hip angle (HP) decreased with the increased gradients: AK = ([0-2% = 1.69%, p < 0.001], [0-7% = 1.13%, p < 0.01]); HP = ([0-2% = 0.22%, p < 0.03], [0-7% = 0.16%, p = 0.456]); KE = ([0-2% = 1.01%, p < 0.001], [0-7% = 1.60%, p < 0.001]). Electromyography (EMG) significantly decreased with the increased gradients in the: tibialis anterior ([0-2% = 22.49%, p < 0.0001], [0-7% = 41.18%, p < 0.0001]) and rectus femoris ([0-2% = 15.35%, p < 0.0001], [0-7% = 29.13%, p< 0.0001]). In contrast, EMG activity was significantly increased in the vastus lateralis ([0-2% = 22.95%, p < 0.0001], [0-7% = 31.15%, p < 0.0001]), gastrocnemius medialis ([0-2% = 21.40%, p < 0.001], [0-7% = 48.37%, p < 0.0001]), and biceps femoris ([0-2% = 190.78%, p < 0.0001], [0-7% = 201.37%, p < 0.0001]). The results indicate that increasing the gradient to 2% did not elicit an increased HR in racewalkers; however, at a 7% gradient, greater muscle activity was required.