Professional Male Volleyball Players Research Articles

Comparison of isometric strength in rotator cuff and scapulothoracic muscles between elite volleyball athletes versus non-athletes.

Volleyball is an exceptionally popular global sport that involves repetitive, rapid, powerful and wide overhead movements, which can seriously alter normal shoulder kinematics. A recognized hallmark of shoulder muscle balance is the ratio of shoulder external (ER) and internal (IR) rotators. By extension, objective measurement of shoulder muscles' strength could help identify at risk athletes and preempt those injuries by engaging in prescriptive strength training programs. This cross-sectional study measured the isometric strengths of 1) shoulder internal and external rotator muscles, as well as the 2) supraspinatus, 3) rhomboid, and 4) middle and inferior trapezius muscles, in addition to calculation of ER:IR ratios, in professional volleyball players as well as in non-athletes. Measurements were made for dominant- and non-dominant upper limbs, in different position of the body (supine and orthostatic) and in different position of upper limb (adducted and abducted position). Our subject population included 11 male professional volleyball players as well as 14 healthy male orthopedic interns from Orthopedics and Trauma school of University of Milano Bicocca. Strengths were assessed by a handheld dynamometer. Each subject's isometric strength was assessed in triplicate in each limb position through a "make test" procedure; the greatest of each triplicate value was the accepted measure of isometric strength. We observed a gradient in muscle strength in the scapulothoracic complex in both groups; the rhomboid, middle trapezius, and lower trapezius ranked from greatest to least strength, respectively. The data suggest also that intrarotators are stronger in rotation adducted position than in rotation abducted position; however, extrarotators seem to be weaker in rotation adducted position than in rotation abducted position. There is also some indication that force development is enhanced in the supine position compared with the orthostatic position. Our findings indicate a scapulothoracic strength gradient with a rank order of strength of the rhomboid>middle trapezius>lower trapezius. The data further suggest that volleyball players have stronger intrarotation in rotation adducted position than in the rotation abducted position, while extra rotation shows the opposite trend. Finally, our data suggest that force development is greater in the supine position compared to the orthostatic position.

Fatigue-Induced Neuromuscular Performance Changes in Professional Male Volleyball Players.

The purpose of the present study was to assess pre-post practice changes in countermovement vertical jump (CVJ) force-time metrics and to determine the relationship between internal and external load variables within a cohort of professional male volleyball players. Ten elite athletes competing in one of the top professional European leagues participated in the present study. While standing on a uni-axial force plate, each athlete performed three CVJs immediately prior to the regular training session. Each athlete wore an inertial measurement unit (VertTM) through an entire practice from which the following external load metrics were obtained: Stress (i.e., an algorithm-derived metric used to quantify the percentage of high-impact movements), Jumps (i.e., the total number of jumps performed during the practice session), and Active Minutes (i.e., the total amount of time performing dynamic movements). Immediately post-practice, each athlete completed another set of three CVJs and reported their subjective measure of internal load using a Rating of Perceived Exertion (RPE) scale (Borg CR-10). While no statistically significant differences were observed in any of the force-time metrics examined in the present study pre-post practice (e.g., eccentric and concentric peak and mean force and power, vertical jump height, contraction time, countermovement depth), our findings indicate a strong positive association between RPE and Stress (r = 0.713) and RPE and Jumps (r = 0.671). However, a weak non-statistically significant correlation was observed between RPE and Active Minutes (r = -0.038), indicating that internal load seems to be more dependent on the intensity rather than the duration of the training session for this sport.

Using inertial measurement units for quantifying the most intense jumping movements occurring in professional male volleyball players

The purpose of this study was to use an inertial measurement unit (IMU) to analyze variations in the jump outcomes concerning weekly training days, and the dependencies between the number of jumps per minute and the jump height. An experimental research design was adopted across three weeks of the final play-off of a volleyball championship. Through an IMU, the external load of seven male elite volleyball athletes of a top rating team from Portuguese 1st Division (age: 30.5 ± 3.5 years; height: 200.2 ± 6.3 cm; body mass: 93.0 ± 8.1 kg; BMI: 23.1 ± 2.3 kg/m2) was monitored. Repeated measures ANOVA was executed to compare the outcomes between training days. It was observed a similar density of jumps during the week. However, when comparing MD-1 to MD-2, a more significant average number of jumps per minute was observed in MD-1 (1.3 ± 0.2 vs. 1.0 ± 0.2). Additionally, a positive, large and significant correlation was registered between the number of jumps and the height of the jump. Those results highlight the benefits of the specific training, leading to greater stimulation and improvement, in a game-like context, of the stretching-shortening cycle, observed in every jump action in volleyball.

Within-week and between-week variability of external and internal load demands of professional male volleyball players

Purpose.The aim of the present study was to analyse the within-week variations according to the internal (rate of perceived exertion [RPE], and session-RPE) and external (jump height average, minimum jump, maximal jump, range of jump, number of jumps and density) intensity.Methods.Twelve male elite/international volleyball athletes from the Portuguese 1st division (age: 21.7 ± 4.19 years of age; experience: 6.2 ± 3.8 years; body mass: 85.7 ± 8.69 kg; height: 192.4 ± 6.25 cm; body mass index: 23.1 ± 1.40 kg/m<sup>2</sup>) participated in this study. The players were monitored over 26 microcycles, 101 training sessions, and 20 matches. To assess the workload, the CR10 Borg scale and an inertial measurement unit (IMU) were used.Results.According to the internal workload, RPE revealed significant differences between MD-4 and MD-2, MD-4 and MD1, MD-3 and MD-1, and MD-2 and MD-1 (<i>p</i> < 0.05). In the same line, session RPE showed significant differences between MD-4 and MD-2, MD-4 and MD-1, MD-3 and MD-2, MD-3 and MD-1, and MD-2 and MD-1 (<i>p</i> < 0.05). On the other hand, the external load demands revealed statistical differences regarding the number of jumps (MD-4 and MD-2, MD-4 and MD-1, MD-3 and MD-1, and MD-2 and MD-1) and the density of the training sessions (MD-4 and MD-1, and MD-2 and MD-1).Conclusions.The primary findings of this study suggest that higher-intensity training sessions tend to occur during the middle of the week, with a tapering effect observed as the competition date approaches.

Positional Differences in External Load in Professional Male Volleyball Players

Positional Differences in External Load in Professional Male Volleyball Players

Effects of Static, Slow and Fast Dynamic Stretching on Shoulder Ioint Proprioception in Male Volleyball Players with Shoulder Impingement Syndrome

Background and Aims Shoulder impingement syndrome (SIS) can affect the proprioception and disturb the normal neuromuscular reactions that the protect the shoulder joint. There are various therapeutic strategies including stretching exercises to prevent the negative effects of SIS. This study aims to investigate the effects of static, slow and fast dynamic stretching on shoulder joint proprioception in male volleyball players with SIS. Methods Participants were 18 professional male volleyball players (Age: 26.52±1.5 years, weight: 89.72±7.02 kg, height: 196.78±6.32 cm) in Kerman, Iran suffering from SIS who were selected using purposeful and convenience sampling methods. All subjects were randomly performed one type of stretching exercises for three consecutive days at the same hour and their proprioception were measured by the Leighton flexometer and target angle reconstruction with external and internal shoulder rotations before and after stretching. The data were analyzed using repeated measures ANOVA. Results The static stretching signifcantly reduced the shoulder joint proprioception (P=0.001), while the dynamic stretching at different speeds had a significant positive effect on shoulder joint proprioception (P=0.001). There was no significant difference between the two types of slow and fast dynamic stretching (P=0.8). Conclusion It seems that dynamic stretching at different speeds has a better effect on shoulder joint proprioception than static stretching in male volleyball players with SIS.

Cardiac structure and function of elite volleyball players across different playing positions.

Volleyball is a popular Olympic sport but has been little studied. Volleyball players have very distinct roles based on their playing positions. The present study aimed to investigate and compare cardiac functions and structure in elite volleyball players across different playing positions. Left ventricular structure and function were measured using echocardiography in 60 male professional volleyball players (30.6±3.6 years) across five playing positions including libero, opposite players, outside hitters, middle blockers, and setters. Significant differences in most echocardiographic variables were observed among different playing positions, including left ventricular (LV) internal dimension, posterior wall thickness, intact ventricular septum, stroke volume, cardiac output, end-diastolic volume, ejection fraction, and fractional shortening (all P<0.01). End-systolic volume was not different among positions (P=0.167). The opposite players demonstrated greater LV dimension and thickness as well as systolic function than players in other positions (P<0.05). Stroke volume in the setters was significantly lower than those of the opposite players and outside hitters (P<0.05). Regression analysis showed that the playing position independently predicted most of the echocardiographic variables (P<0.05). LV adaptations in volleyball players vary widely according to their playing positions. The opposite players had the most pronounced LV adaptations compared with player in other positions.

Consequences of Patellar Tendinopathy on Isokinetic Knee Strength and Jumps in Professional Volleyball Players.

Patellar tendinopathy (PT) in professional volleyball players can have an impact on their careers. We evaluated the impact of this pathology in this specific population in terms of isokinetic strength and jumping performances. Thirty-six professional male volleyball players (mean age: 24.8 ± 5.2) performed isokinetic knee assessments, single-leg countermovement jumps and one leg hop test. They filled out the Victorian Institute of Sport Assessment-Patella (VISA-P) score. Two groups were assessed: “PT group” (n = 15) and “control group” (n = 21). The VISA-P score was lower in the PT group (p < 0.0001). No difference was found between the isokinetic strength limb symmetry index and the jump performance limb symmetry index. The healthy legs of the control group were compared with the affected (PT+) and the unaffected legs (PT−) of the PT group. Compared with the healthy legs, both PT+ and PT− legs showed decreased values of quadriceps and hamstring strengths. Only PT+ legs scored lower than healthy legs in countermovement jumps and hop tests. No differences were found between PT+ and PT− legs for muscle strengths and jumps. A low correlation existed between quadriceps strength and jumping performances (r > 0.3; p < 0.001). Volleyball players with PT showed a decrease in the isokinetic knee strength. This strength deficit was found both on the symptomatic legs and the asymptomatic ones. Jumps were only significantly altered on the pathological legs. Highlighting that the unaffected limbs were also impaired in addition to the affected limbs may help provide a better adaptation of the rehabilitation management.

Current Implementation of Oslo Sports Trauma Research Center Volleyball Injury Prevention Exercises among Male Professional Volleyball Players in the Gulf Cooperation Council Countries: A Cross-Sectional Survey

Current Implementation of Oslo Sports Trauma Research Center Volleyball Injury Prevention Exercises among Male Professional Volleyball Players in the Gulf Cooperation Council Countries: A Cross-Sectional Survey

Effects of Postactivation Performance Enhancement on The Vertical Jump in High-Level Volleyball Athletes.

The objective of this study was to evaluate the effects of a training session with and without an intervention of postactivation performance enhancement (PAPE) on countermovement jump (CMJ) height, perceived recovery status (PRS), and ratings of perceived exertion (RPEs), followed by a specific volleyball training session. The sample consisted of sixteen professional male volleyball players, with an average age of 26.8±6.1 years and average height of 195.9±6.7 cm, randomly divided into a group with PAPE intervention (GPAPE) (n=8), and a control group (CTRL) without PAPE intervention (n=8). The control group carried out the training session with plyometric exercises, and the GPAPE added conditioning protocols for PAPE to plyometric training, followed by a technical tactical volleyball session. At the end of the training session, there was an increase of 16.3% in the height of the CMJ in the GPAPE, while the CTRL showed a decrease of 5% in the height of the CMJ. PRS and RPE variables did not differ between the groups. It was concluded that PAPE had a positive effect on the height of the vertical jump after plyometric training, which was maintained until the end of the technical and tactical volleyball session.

Using an overhead target increases volleyball-specific vertical jump performance

In volleyball, spikes, and block jumps are among the most important movements when earning points and impacting performance. Many studies have found a greater jump height after acutely augmented feedback and extrinsic focus of attention on vertical jump height. However, there are limited studies on the long-term effects of using an overhead target on volleyball-specific vertical jumps (block and spike jumps). Therefore, the aim of the current study was to investigate the effects of using an overhead target on the vertical jump heights of volleyball players. Twenty-five professional male volleyball players (age: 24.44 ± 3.78 years; height: 1.82 ± 8.79 cm; body mass: 80.96 ± 9.37 kg) were randomly assigned either to the experimental group with an overhead target (OHT) ( n = 9), group without an overhead target (WOHT) ( n = 10), or the control group ( n = 8). The OHT group performed vertical jumps with an overhead target before their regular training program, while the WOHT group completed vertical jumps without an overhead target before their regular training program. Meanwhile, the control group performed only their regular training program, which was a 5 week (3 days per week) program. All participants’ spike jump (SPJ) and block jump (BJ) results were assessed before and after the intervention. A repeated-measures analysis of variance (3 × 2) did not reveal any significant between-group interactions for SPJ and BJ ( F = 7.32, p &lt; 0.11 and F = 1.59, p &lt; 0.22 respectively), but significant results were found for the time effect ( F = 96.33, p &lt; 0.01 and F = 132.25, p &lt; 0.01 respectively) and group × time interaction ( F = 42.59, p &lt; 0.01 and F = 61.52, p &lt; 0.01, respectively). While the pre- and post-tests for BJ and SPJ values did not change in the control group ( p &gt; 0.05), both of these values increased in the OHT group (60.00 ± 5.95–67.44 ± 5.98 cm, p &lt; 0.01 for d = 1.24 and 49.00 ± 6.74–56.22 ± 5.29 cm p &lt; 0.01 for d = 1.19, respectively) and WOHT group (57.50 ± 4.86–60.50 ± 4.99 cm, p &lt; 0.01 for d = 0.60 and 47.75 ± 4.65–50.25 ± 3.69 cm, p &lt; 0.01 for d = 0.59). It has been suggested that trainers and professionals can use an overhead target to increase the BJ and SPJ heights of professional volleyball players.

Relationship between vertical jumping ability and endurance capacity with internal training loads in professional volleyball players during preseason.

This study aimed to quantify internal training load and changes in vertical jumping ability and endurance capacity of professional volleyball players during the preseason, and to explore relationships between players' physical qualities at the beginning of the preseason with internal training load accumulated during the first two weeks of training. Sixteen male professional volleyball players from a team participating in the Brazilian National Super League took part in the study. Before and after a 10-week preseason, their vertical jumping ability and endurance capacity were assessed by squat jump, countermovement jump without and with arm swing, and YoYo endurance test, level 1. The internal training load was quantified by the session rating of perceived exertion method. Results were analyzed using analysis of variance, magnitude-based inference and Pearson's correlation. The internal training load varied between 1388±111 arbitrary units (a.u.) and 3852±149 a.u., and performance in all the tests was positively changed (small to moderate effect sizes) at end of preseason training. Significant (P<0.05) very large and large correlations were observed between squat jump (r=-0.81) and YoYo endurance test (r=-0.64) performances and internal training load accumulated during the first two training weeks, respectively. The internal training load and training strategies undertaken by the investigated team were effective to improve players' vertical jumping ability and endurance capacity. Coaches need to improve these physical qualities of volleyball players in order to improve their tolerance to training.

Kümeleme Set Direnç Antrenmanı Profesyonel Voleybol Sporcularında Sprint, Çabukluk, Kuvvet ve Dikey Sıçramada Daha İyi Gelişimler Sağlayabilir

Objective: The purpose of this study is to compare the effects of six-week traditional and cluster resistance training (CRT) on sprint, agility, maximal strength and vertical jump parameters in Professional volleyball players. Material and Methods: Twenty-eight Professional male volleyball players participated in the present study. Athletes were randomly assigned into two training groups: traditional resistance training (TRT) (n=14) and CRT (n=14) groups. Both training groups performed the resistance trainings during six-week on three nonconsecutive days (Monday, Wednesday and Friday). Subjects underwent countermovement vertical jump, agility t, 10-m, 20-m sprint, one repetition maximal (1RM) back squat (BS), bench press (BP), pull over (PO), military press (MP) and dead lift (DL) tests prior to and after sixweek resistance training program. Results: Both training groups demonstrated statistically significant improvements in 1RM, sprint times, vertical jump displacement and agility t-test (p<0.05). As compared with the TRT group, the CRT group demonstrated large significant gains in 1RM BS (CRT: 4.76%±2.34% vs. TRT: 2.21%±1.57%; p=0.002, effect size (ES)=0.51), 1RM PO (CRT: 7.59%±4.57% vs. TRT: 3.96%±3.65%; p=0.004, ES=0.91), 1RM DL (CRT: 4.19%±2.76% vs. TRT: 1.79%±2.92%; p=0.024, ES=0.875) and 1RM BP (CRT: 5.82%±4.58 vs. TRT: 2.66%±3.51; p=0.033, ES=0.31). As compared with the TRT group, the CRT group demonstrated significantly higher gains in 20-m sprint (CRT: 6.48%±4.70% vs. TRT: 1.81%±1.04%; p=0.001, ES=1.93), agility t-test performances (CRT: 11.35%±3.89% vs. TRT: 2.28%±1.85%; p=0.000, ES=0.81) and vertical jump displacement (CRT: 6.21%±0.90% vs. TRT: 2.13%±0.61%; p=0.000, ES=5.45). Conclusion: This study suggests that CRT provides more advantages than TRT for professional volleyball players.

Knee extensor/flexor muscle torque and jump performance in male volleyball players: effect of experience and torque-angle-velocity relationships

Background and objective: There are many studies that have examined the differences in isokinetic strength performance differences in athletes; however, observing these angular velocity-dependent differences on surface maps is a very practical and useful application. The aim of this study was to determine the angular velocity-dependent isokinetic knee extensor/flexor muscle strength and jump performance and to compare the test results and 3D torque-angle-velocity surface maps of amateur and professional volleyball players. Materials and methods: We included 25 well-trained male volleyball players (14 professionals and 11 amateurs) with a mean age of 21.8 ± 2.6 years (range 18--27 years) in this cross-sectional study. The dominant knee concentric muscle contractions were analyzed at 300, 120, and 60◦/s angular velocities to determine peak torque (PT), total work (TW), mean power (MP), angle of peak torque (APT), and hamstring-to-quadriceps torque ratio (H:Q). Vertical jump performance was assessed using countermovement jump (CMJ) test. These data were processed using a MATLAB algorithm for constructing the 3D torque-angle-velocity surface maps. Results and conclusions: Significant differences were identified for extensor--flexor PT between PRO and AT at 300 and 120◦/s (p &lt; 0.05). Moreover, there were significant differences between groups for MP and APT at 300 and 120◦/s for TW at all velocities. CMJ test results were significantly different between the groups (p &lt; 0.05). Amateur and professional male volleyball players showed different concentric knee strengths across isokinetic velocities and different eccentric strengths on CMJ test. 3D surface maps can play an important role in the comparative analysis of athletes with different sports backgrounds or in performance analyses when tracking individual development and provide a detailed and understandable perspective in revealing differences. It can also be of help in detection of possible deficits in muscle strength and load range before and after potential injuries.

Dorsiflexion and dynamic postural control asymmetry in elite male volleyball players

Objective: Movement assymetry is considered a potential risk factor for musculoskeletal injury in sport. Sports such as volleyball are thought to cause movement assymetries due to specific sporting demands. Further, between limb comparisons are often used for return to sport decisions. Despite this, little information is available regarding the presence of assymetry in volleyball athletes. Therefore the purpose of this investigation was to determine the presence of assymetry in dorsiflexion range of motion (DFROM) and dynamic postural control variables, factors important in return to sport decisions, both the group and individual level in professional male volleyball players. Secondarly, we aimed to better understand the role of DFROM on the Star excursion balance test (SEBT), a measure of dynamic postural control. Method: Thirty-two Professional male volleyball players (age: 24.7±5.53 years, height: 190.6±7.63 cm., weight: 84.5±9.28 kg., BMI: 23.22±1.62 kg/m2) participated in this investigation. All participants reported for a single test session during which DFROM and the SEBT were assessed on both limbs. Results: There was a significant group difference (p <0.05) between limbs for the normalized anterior (landing leg: 73.3 ± 6.2%; non-landing leg: 71.4 ± 6.8% ) posteromedial (landing leg: 112.6±9.3%; non-landing leg: 107.6±10.8%) and posterolateral (landing leg: 114.5±8.1%; non-landing leg: 111.4±9.4%) SEBT reach direction. The anterior and posteriomedial but not the posteriolateral reach differences exceeded the minimal detectable change score for the SEBT. At the individual level, the vast majority of participants demonstrated minimal assymetry. Significant correlations were found between DFROM and the anterior SEBT reach (r = 0.36 to 0.39, p<0.04) as well as the posteriolateral SEBT reach (r= 0.47 to 0.50, p<0.01). Conclusions: Professional volleyball players do not have DFROM or dynamic postural control assymetries but DFROM can influence dynamic postural control.

Isokinetic Performance of Shoulder External and Internal Rotators of Professional Volleyball Athletes by Different Positions

This study aimed to exam the isokinetic shoulder rotator strength of professional volleyball athletes, by playing positions. This cross-sectional study included a total of 49 healthy male professional volleyball players. We measured the isokinetic strength of the external rotator (ER) and internal rotator (IR) muscles and compared the dominant and non-dominant shoulders at angular speeds of 60°/s and 180°/s. In ER, all positions of players had similar strength between the dominant shoulder and non-dominant shoulders. Conversely, all playing positions except libero had stronger strength in dominant shoulder than that in the non-dominant shoulder. The ER/IR ratio in the dominant shoulder was significantly lower only for the attacker (outside hitter and opposite) at 60°/s and 180°/s (P < 0.0001; P = 0.0028 respectively) and blocker at 60°/s (P = 0.0273) when compared with non-dominant shoulder. Furthermore, the attacker had a lower ER/IR ratio in the dominant shoulder than setter and libero at 60°/s and 180°/s. For elite volleyball players without injury, the dominant shoulder had a higher strength of internal rotation, causing the relative muscle imbalance than the non-dominant shoulder, especially for the attacker and blocker positions. Training program should be individualized for each playing position to improve the imbalanced shoulder.

Differential Nasal Expression of Heat Shock Proteins 27 and 70 by Aerobic Exercise: A Preliminary Study.

Purpose: Exercise modifies airway immune responses and susceptibility to infection. We investigated the effects of exercise on two HSPs (heat shock proteins), quantifying expression levels in nasal mucosa of both professional competitive athletes and non-athletes for comparison.Method: We used western blot technique to determine expression levels of HSPs in primary human nasal epithelial cells (HNECs). Nasal lavage (NAL) fluids were collected from 12 male professional volley ball players and 6 healthy males pre-submaximal exercise (running for 30 min at 70-80% of maximal heart rate) and post-submaximal exercise. Expression levels of HSP27, HSP70, Interleukin (IL)-8, and Tumor necrosis factor (TNF)-α in NAL fluids were quantified by enzyme-linked immunosorbent assay (ELISA), and difference of the level between pre-submaximal exercise and post-submaximal exercise was statistically analyzed. Antibacterial assay using Staphylococcus aureus was performed to assess the immunological role of HSPs in NAL fluids.Results:. In non-athlete controls, HSP27, HSP70, and IL-8 were unchanged after exercise. In the professional athletes, HSP70 expression was declined significantly (p<0.05), but HSP27 was not significantly changed. IL-8 and TNF-α did not show significant difference, either. By antibacterial assay, it was found that the number of active bacterial populations were influenced by the presence or absence of HSP27 and HSP70 in NAL fluids.Conclusion: HSP27 and HSP70 were present in NAL fluids of enrolled subjects, and the effect of exercise on the level HSPs was different between professional athletic competitors and non-athletes. As the number of active bacterial population was influenced by the presence or absence of nasal HSP27 and HSP70, we suggest that HSP27 and HSP70 may play immunological function in NAL fluids.

Short-term branched-chain amino acid supplementation does not enhance vertical jump in professional volleyball players. A double-blind, controlled, randomized study.

To the best of the authors' knowledge, no previous studies have described the effect of branched-chain amino acids (BCAA) on vertical performance during a week in professional volleyball players. This study assessed BCAA supplementation for a week, aiming to improve vertical jump performance in male professional volleyball players. Twelve male volleyballers were randomly assigned to a BCAA group (n = 6) or a control group (n = 6). The BCAA group ingested 21 g over a week, 7 g per day on Monday, Wednesday, and Friday, before a volleyball training session, while the control group drank a placebo drink. Participants performed 8 maximal countermovement jumps (CMJ); the 3 CMJs on Monday and Wednesday were evaluated after warm-up, after plyometric training, and at the end of the training session; and the 2 CMJs on Friday were evaluated after warm-up, and at the end of the training session. Compared with baseline, no significant differences in CMJ over the week were observed in BCAA or control group, neither between groups. The results indicated that 21 g of BCAA supplementation over a week did not improve vertical jump performance in professional volleyball players.

Morpho-textural changes of the patellar tendon in professional volleyball players: a six month longitudinal study

Abstract Introduction Tendinopathy is a term used to describe a clinical presentation of pain and dysfunction, which, at times, is accompanied by pathologic structural changes in the tendon matrix. Jumper's knee has been studied for some time, however the etiology is still unknown. The deep fibers of the proximal region are the most affected area in tendinopathies affecting the patellar tendon. Ultrasound (US) scanning may have the greatest sensitivity for confirming clinically diagnosed patellar tendinopathy compared with other imaging techniques such as magnetic resonance. Some studies have found that a minimum of six months is required to observe significant structural changes, although other studies reveal that structural changes can be visible in a shorter period of time. Thus, sonography has been used to evaluate quantitative variables such as thickness, echogenicity, texture measures and the internal tendon matrix. Objective The purpose of this study was to evaluate the sonographic behavior of morpho-textural changes of the patellar tendon in professional male volleyball players over a one year season. Material and Methods This is an observational, longitudinal and analytical study. A sample of 66 patellar tendons from 33 volleyball players of the Spanish super league was recruited, with an average of: 28 years, 86kg and 192cm. An ultrasound scan was performed using the Sonosite Titan ultrasound system, L38, 5–10 MHz, with a cross section of 5mm from the lower pole of the patella. Two depths were analyzed: a.39mm: echogenicity, echogenicity variation, circularity, width and thickness. b.24mm: entropy and contrast. Statistical analysis and analysis of variance (ANOVA) was performed for repeated measures and, in addition, the effect size was calculated with Cohen's d. The confidence interval was 95%. SPSS Statistics software was used. Results For textural variables: contrast increased significantly with an average effect size, and entropy showed no significant difference. Circularity was significantly lower. Width was shown to be significantly greater, with an average effect size, while thickness was reduced significantly. Regarding echogenicity, no significant changes were detected and variation in echogenicity did not show significant changes. Conclusions Imaging analysis could be a potential tool to detect changes in the pattern of patellar tendons. Some morpho-textural changes were found in male volleyball players: the textural contrast variable increases significantly throughout the annual season, meaning that the tendon becomes slightly flatter and loses circularity in its transverse section. The entropy and echogenic parameters obtained from the gray-scale histogram did not reveal any significant changes.

The Relationship between Vitamin D Status and Rotator Cuff Muscle Strength in Professional Volleyball Athletes.

This study aimed to examine the vitamin D status of professional volleyball athletes and to determine its correlation with shoulder muscle strength. We included 52 healthy male professional volleyball players (23.2 ± 4.5 years), who were categorized by vitamin D status (<20 ng/mL: deficiency, 20–30 ng/mL: insufficiency, and >30 ng/mL: sufficiency). We examined the strength of the internal rotator (IR) and external rotator (ER) muscles of the shoulder by using an isokinetic dynamometer. Fourteen players (26.9%) had vitamin D deficiency, 24 players (46.2%) were vitamin D-insufficient, and 14 players (26.9%) were vitamin D-sufficient. There was no significant correlation between vitamin D level and shoulder muscle strength at 60°/s (IR, r = 0.159, p = 0.26; ER, r = 0.245, p = 0.08) and at 180°/s (IR, r = −0.093, p = 0.51; ER, r = −0.037, p = 0.79). Moreover, the isokinetic shoulder strengths were not significantly different across the three groups in all settings. In conclusion, vitamin D insufficiency was common in elite volleyball players. Though not being associated with isokinetic muscle weakness, vitamin D levels should be regularly monitored, and vitamin D should be supplied to young elite athletes, considering its importance for musculoskeletal health.