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This study examines electromyographic activity of the latissimus dorsi and the posterior deltoid, which act as competitors and agonists, respectively, during the rotational movement in the forehand drive technique with an open stance, among young tennis players aged 12-16. Eleven athletes participated in the research. The average of the maximum activation of the latissimus dorsi recorded with EMG, in the movement of the forehand drive corresponds to 4,15±1,137 and for the posterior deltoid, the maximum activation was 6,70±1,90. The results of the measurements indicate differences in the sequence of activation between the two muscles. The posterior deltoid was the second muscle to contract after the latissimus dorsi. At the start of the rotating action, the latissimus dorsi was most fully activated, while the maximum activation posterior deltoid was towards the end of the movement. The t-test showed P

Context: Bridge exercises are extensively used in trunk-strengthening programs. The aim of this study was to investigate the effect of bridging duration on lateral abdominal muscle thickness and gluteus maximus activation. Design: Cross-sectional. Methods: Twenty-five young males participated in this study. Transversus abdominal (TrA), external and internal oblique ultrasound thickness, gluteus maximus electromyographic activation, and sacral tilt angle were simultaneously measured for every second during 30-second bridging exercise. The contraction thickness ratio and root mean squared signal (normalized to maximum isometric contraction signal) during 6 exercise durations (from 0 to 5, 10, 15, 20, 25, and 30 s) were also calculated and compared using analysis of variance designs. Results: TrA and internal oblique contraction thickness ratio and gluteus maximus root mean squared increased during the first 8 to 10 seconds and remained elevated until the end of the 30-second exercise (P P P Conclusions: Bridge exercises longer than 10 seconds may be better for promoting TrA recruitment than bridges of shorter duration. Clinicians and exercise specialists could adjust the duration of bridge exercise based on the aims of the exercise program.

The objectives of the study were to examine the incident rate (IR), characteristics, and mechanisms of muscle injuries of 121 men amateur soccer players that voluntarily participated in this project. Sixty-five muscle injuries with an overall IR of 3.62/1000 h, 95% CI 2.7-4.5, were reported. The most frequently injured muscle groups were the hamstrings (IR 1.78/1000 h, 95% CI 1.1-2.3), followed by the adductors (IR 1.5/1000 h, 95% CI 0.93-2.06). Most muscle injuries were characterized as mild (IR 2.3/1000 h, 95% CI 1.53-2.92) or minimal (IR 1.28/1000 h, 95% CI 1.16-2.39. Higher incidence of injury sustained during matches (IR 14.09 injuries/1000 h, 95% CI 9.49-18.7), than in training (IR 1.88 injuries/1000 h, 95% CI 1.19-2.56). The most frequent injury mechanisms were high-speed running (84.4%) and change of direction (44.4%), for hamstring and adductors-related groin injuries, respectively. Players aged over 24 years had a 7-fold increased risk to sustain a hamstring injury but a lower risk to sustain an adductor-related groin injury. Injury prevention and rehabilitation management strategies may reduce muscle injury rates in amateur soccer.

The present study aimed to examine the differences in ankle and knee joint kinematics between the flat, slice, and topspin tennis serves. Twelve young tennis players (six boys, and six girls) aged 12-16 years old, performed flat, slice and topspin serve whilst three-dimensional body kinematics were recorded using an optoelectronic camera system. Ankle plantarflexion/dorsiflexion and knee extension/flexion angular positions were recorded at two-time instants: first, at the time of maximum knee flexion and, second, at time of ball to racket contact. Analysis of variance designs showed that the knee flexion angle of the back leg differed significantly between the three service types (P < 0.001). Further, the rear leg ankle angle at maximum flexion also significantly differed between the three serves (P < 0.004). It was observed that tennis players perform topspin and slice serves with smaller joint angles than flat serves, probably, because the former is being used as a second serve in the game. Τhe ankle, which is the closest point of the kinetic chain at the start of power generation, plays an important and different role in the performance of the three serve types. Therefore, the synergy of the ankle joint is very important in the initial phase of serve for the transfer of forces. Coaches should review the technical issues of serve movement based on the flexibility of the ankle joint because the limited ankle range of motion does not help to transfer forces from the ground.

The purpose of the study was to assess the influence of short, intermediate, and long muscle lengths on dorsiflexor force steadiness and the discharge characteristics of motor units in tibialis anterior during submaximal isometric contractions. Steady contractions were performed at 5 target forces (5, 10, 20, 40, and 60% maximal voluntary contraction, MVC) for 3 ankle angles (75°, 90°, and 105°). MVC force was less (p = 0.043) at the smallest joint angle compared with the other two angles. The absolute (standard deviation) and normalised amplitudes (coefficient of variation) of the force fluctuations were similar for all 3 ankle angles at each target force. The coefficient of variation for force decreased progressively from 5% to 20% MVC force and then it plateaued at 40% and 60% MVC force. At all target forces, the mean discharge rate (MDR) of the motor units at 75° was greater than at 90° (p = 0.006) and 105° (p = 0.034). Moreover, the MDR was similar for 5% and 10% MVC forces and then increased gradually until 60% MVC force (p

A number of reviews have collated information on the impact of warming-up, physical exertion and recovery strategies on physical, subjective and physiological markers in soccer players yet none have solely analyzed their potential effects on components of kicking performance. To systematically analyse the influence of warm-up, exercise and/or recovery-related strategies on kicking performance in male soccer players and provide a critical appraisal on research paradigm related to kicking testing constraints and data acquisition methods. A systematic literature search was performed (until July 2020) in PubMed, Web of Science, SPORTDiscus, Scopus and ProQuest. Studies in male soccer populations, which included the effects of warm-up routines, physical exercise and/or recovery-related interventions, reported on comparisons pre–post or between experimental conditions and that computed at least one measure of kicking kinematics and/or performance were considered. Methodological quality and risk of bias were determined for the included studies. Constraints related to kicking testing and data acquisition methods were also summarized and discussed. Altogether, 52 studies were included. Of these, 10 examined the respective effects of a warm-up, 34 physical exercise, and 21 recovery-related strategies. The results of eight studies showed that lower limb kinematics, kicking accuracy or ball velocity were improved following warm-ups involving dynamic but not static stretching. Declines in ball velocity occurred notably following intermittent endurance or graded until exhaustion exercise (three studies in both cases) without inclusion of any ball skills. In contrast, conflicting evidence in five studies was observed regarding ball velocity following intermittent endurance exercise interspersed with execution of ball skills. Kicking accuracy was less frequently affected by physical exercise (remained stable across 14 of 19 studies). One investigation indicated that consumption of a carbohydrate beverage pre- and mid-exercise demonstrated benefits in counteracting the potentially deleterious consequences of exercise on ball velocity, while four studies reported conflicting results regarding kicking accuracy. Most evidence synthesized for the interventions demonstrated moderate level (77%) and unclear-to-high risk of bias in at least one item evaluated (98%). The main limitations identified across studies were kicks generally performed over short distances (50%), in the absence of opposition (96%), and following experimental instructions which did not concomitantly consider velocity and accuracy (62%). Also, notational-based metrics were predominantly used to obtain accuracy outcomes (54%). The results from this review can help inform future research and practical interventions in an attempt to measure and optimise soccer kicking performance. However, given the risk of bias and a relative lack of strong evidence, caution is required when applying some of the current findings in practice. PROSPERO ID: CRD42018096942.

The aim of this study was to examine the intra- and inter-muscular differences of the hamstring muscles using textural analysis of ultrasound (US) images, and the relationship between textural indicators with hamstring torque. Transverse US scans were obtained from 10 young males from four different measurement sites along the thigh of each individual hamstring muscle at rest. Maximum-knee-flexion isometric torque measurements were also obtained. Texture analysis was applied to US images, and five gray-level co-occurrence matrix (GLCM) features were quantified: entropy (ENT), angular second moment (ASM), inverse difference moment (IDM), contrast (CON) and correlation (COR). The intraclass correlation coefficients ranged from 0.77 to 0.99, and the standard error of measurement ranged from 0.06 to 10.05%, indicating high test-retest reliability. Analysis of the variance indicated significant differences between measurement sites and individual muscles, with the proximal measurement sites having greater values for ASM, IDM and COR and lower values for ENT and CON compared with the distal sites. Additionally, only the COR at the proximal measurement site exhibited a significant relationship (r = -0.66) with strength. The present study indicated significant differences among hamstrings and measurement locations with respect to the textural analysis and may provide a novel indicator of hamstring functional properties.

The aim of our study was to compare maximal force, force steadiness, and discharge characteristics of motor units in tibialis anterior during contractions with the dorsiflexors of the dominant and nondominant legs at low-to-moderate target forces and three ankle angles.Twenty young adults performed maximal and submaximal isometric contractions (5%, 10%, 20%, 40%, and 60% of maximal voluntary contraction (MVC)) with the dorsiflexors of the dominant and nondominant legs at three ankle angles (75°, short length; 90°, intermediate length; 105°, long length). High-density EMG signals from the tibialis anterior muscle of each leg were recorded.Maximal force (average dominant, 182.9 ± 64.5 N; nondominant, 179.0 ± 58.8 N) and the fluctuations in force, quantified as absolute (SD) and normalized amplitudes (coefficient of variation (CoV)), were similar between the two legs across the three ankle angles (average CoV for dominant, 1.5% ± 1.0%; nondominant, 1.7% ± 1.3%). The CoV for force for both legs decreased from 5% to 20% MVC force, and then it plateaued at 40% and 60% MVC force. EMG amplitude, mean discharge rate of motor units, discharge variability (interspike interval), and the variability in neural drive (filtered cumulative spike train) were similar between the two legs across the submaximal contractions.MVC force and force steadiness were similar across ankle angles and target forces between the dominant and nondominant legs. The attributes that underlie the self-reported identification of a dominant leg were not associated with the force capacity or the control of force for the dorsiflexor muscles, at least during isometric contractions.

Repeated high-intensity running (RHIR) exercise is known to affect central and peripheral functioning. Declines in RHIR performance are exacerbated by environmental heat stress. Accordingly, the use of post-exercise cooling strategies (COOL) is recommended as it may assist recovery. The present study aimed to investigate, in a hot environment (> 30ºC), the effects of local COOL following RHIR on indices of soccer kicking movement and performance in youth soccer. Fifteen academy under-17 players (16.27 ± 0.86 years-old; all post-PHV), acting as their own controls, participated. In #Experiment 1, players completed an all-out RHIR protocol (10 × 30 m bouts interspersed with 30 s intervals). In #Experiment 2, the same players performed the same running protocol under two conditions, 1) 5 minutes of COOL where ice packs were applied to the quadriceps and hamstrings regions and, 2) a control condition involving only passive resting. In both experiments, perceptual measures [ratings of perceived exertion (RPE), pain and recovery], thigh temperature and kick-derived video kinematics (hip, knee, ankle and foot) and performance (ball speed and placement) were collected at baseline and post exercise and intervention. In the first experiment, RHIR led to moderate-to-large increases (p < 0.03) in RPE (d = 4.08), ankle eversion/inversion angle (d = 0.78) and mean radial error (d = 1.50) and small-to-large decreases (p < 0.04) in recovery (d = -1.83) and average/peak ball speeds (d = -0.42–-0.36). In the second experiment RPE (p < 0.01; Kendall’s W = 0.30) and mean radial error (p = 0.057; η2 = 0.234) increased only post-control. Significant small declines in ball speed were also observed only post-control (p < 0.05; d = 0.35). Post-intervention CMfoot velocity was moderately faster in COOL as compared to control (p = 0.04; d = 0.60). RHIR acutely impaired kicking movement, ball speed and placement in youth soccer players. However, a short period of local cryotherapy may be beneficial in counteracting declines in indices of kicking performance in hot environment.Trial registration number#RBR-8prx2m - ReBEC Brazilian Clinical Trials Registry

Made available in DSpace on 2020-12-12T02:47:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Aim: The main purpose of the study was to investigate kicking kinematics and performance in young-trained soccer players according to age, playing status, and biological maturity.Methods: Youth male soccer players (N = 105) from five age groups (under-11, under-13, under-15, under-17, and under-20) were evaluated. Four digital video cameras (300 Hz) captured the participants’ lower extremity and ball kinematics during penalty kick trials using dominant limb.Results: It was possible to identify non-linear differences in angular joint kinematics (displacement and velocity) of hip, knee and ankle across age-groups. Kicked ball speed and lower extremity mechanical factors discriminated among under-15 players with distinct status (e.g., ball speed and foot-to-ball speed ratio: starters > non-starters and non-participating substitutes; effect size = 1.05 to 1.49 [large]). Estimated maturity offset was not correlated with performance outputs in any age-group (r = −0.28 to 0.39; P > 0.05).Conclusion: We conclude that from ages ~10 to 19 years, differences in kicking kinematics and performance vary across time in youth players. Transition phase between under-13 to under-15 appears the most sensible period for powerful instep kick performance development. Kicking speed in youth soccer is discriminated according to player status, but not estimated biological maturity. LaBioCoM Biomechanics and Motor Control Laboratory School of Physical Education and Sport Campus Ribeirão Preto University of São Paulo FMRP Faculty of Medicine at Ribeirão Preto University of São Paulo MOVI-LAB Human Movement Research Laboratory School of Sciences Physical Education Department UNESP São Paulo State University Laboratory of Neuromechanics Department of Physical Education and Sports Sciences of Serres Aristotle University of Thessaloniki Department of Sports Center of Physical Education and Sports (CEFD) Federal University of Espírito Santo LIB Laboratory of Instrumentation for Biomechanics FEF Faculty of Physical Education UNICAMP MOVI-LAB Human Movement Research Laboratory School of Sciences Physical Education Department UNESP São Paulo State University

Bridging exercises with abdominal hollowing are often used as a regimen for improving spinal stability. Lately, this type of training has become very popular among elite athletes, creating a need for more demanding exercises. The purpose of this study was to investigate whether the use of additional external resistance is beneficial for abdominal muscle recruitment during bridge exercise. Tissue movement of the transversus abdominis (TrA) and the rectus abdominis (RA) was recorded with the use of two synchronized ultrasonic devices, in 20 healthy college students. From the hook-lying position participants were examined in eight different exercise conditions: a) rest, b) abdominal drawing-in maneuver (ADIM), c) bridge, d) bridge- ADIM, e) bridge with 10KG, f) bridge- ADIM with 10KG, g) bridge with 20KG and h) bridge-ADIM with 20KG. Analysis of variance (ANOVA) showed a statistically significant increase in TrA thickness when performing the bridge exercise combined with ADIM compared to rest mode (p < .05). RA thickness decreased when the ADIM was performed, compared to rest (p < 0.05). No significant difference in TrA and RA thickness when exercising with and without external resistance was observed (p > 0.05). The main outcome of this study was that external loading provided some extra level of difficulty, yet it was not beneficial for abdominal muscle recruitment, when performing a supine bridge exercise.

Core stability exercises are regular part of exercise programs for asymptomatic individuals across ages. The purpose of this study was to examine deep abdominal and multifidus muscle thickness in children and adults and to determine reliability of the rehabilitative ultrasound (RUSI) imaging. Transversus abdominis and lumbar multifidus thickness at rest and during core stability exercise were examined in pre-pubertal children (N = 23), adolescents (N = 20), young adults (N = 21) and middle-aged adults (N = 22). Thirty-nine participants were re-tested one week after to establish reliability. Muscle thickness at rest was lower in children and adolescents compared with young and middle-aged adults (p < 0.008). Young adults displayed the highest relative transversus abdominis thickness upon contraction (p < 0.008). Lumbar multfidus contraction thickness was greater in young-adults than middle-aged adults and pre-pubertal children (p < 0.008), but it was similar between young-adults and adolescents (p > 0.008). Reliability was high for both muscles (ICC3,3 = 0.76 - 0.99). The age-related differences in muscle thickness indicate that core stability exercises may be beneficial for children and middle-aged adults.

The purpose of this study was to prospectively monitor and analyze injuries in Greek amateur male soccer players over one competitive season. One hundred and thirty male soccer players in a regional amateur league participated in this study. Injury data and exposure were collected from six teams during training and competition match over one season (2018/19). Injuries were collected weekly and were classified by setting, mechanism, severity, type, calendar distribution, period of injury occurrence, and anatomical location. A total of 103 injuries were recorded during the season, with an incident rate (IR) of 5.5 injuries/1000 h with 95% confidence intervals (CI) values of 4.45 (lower limit) and 6.09 (upper limit). Furthermore, IR was greater for the posterior thigh (IR 1.83/1000 h, 95% CI 1.21–2.44) and hip/groin complex (IR 1.45/1000 h, 95% CI 0.90–1.99) compared to other anatomical locations. Similarly, muscle injuries had greater IR (IR 3.61/1000 h, 95% CI 2.74–4.47) than other tissues. Amateur soccer players had a seven-fold greater chance of getting injured during games (IR 20.76/1000 h, 95% CI 15.28–26.24) rather than during training (IR 3.077/1000 h, 95% CI 2.16–3.80), while injury rates were higher towards the end of a session and peaked in October and February of the season. Based on these results, amateur soccer may benefit from injury prevention strategies incorporated into their regular training practice and focus on muscle injuries, especially in the posterior thigh and the hip/groin complex.

Hamstring strains are a frequent injury in sports and are characterized by a high recurrence rate. The aim of this review was to examine the muscle and tendon architecture in individuals with hamstring injury. A systematic literature search in four databases yielded eleven studies on architecture following injury. Differences in the fascicle length (FL), pennation angle (PA) and muscle size measures (volume, thickness and physiological cross-sectional area) at rest were not significantly different between the previously injured limb and the contralateral limb (p > 0.05). There was moderate evidence that biceps femoris long head (BFlh) FL shortening was greater during contraction in the injured compared to the contralateral limb. The BFlh FL was smaller in athletes with a previous injury compared to uninjured individuals (p = 0.0015) but no differences in the FL and PA of other muscles as well as in the aponeurosis/tendon size were observed (p > 0.05). An examination of the FL of both leg muscles in individuals with a previous hamstring strain may be necessary before and after return to sport. Exercises that promote fascicle lengthening of both injured and uninjured leg muscles may be beneficial for athletes who recover from a hamstring injury.

The tensor of vastus intermedius is a newly discovered muscle that is located at the anterior compartment of the thigh. The aim of the present study is to report, assess and synthetize the existing evidence on the anatomy, variation and morphological characteristics of the TVI as well as to examine its clinical importance. A systematic review was performed evaluating both anatomical and medical imaging studies which provided information about TVI anatomy, prevalence, variations and morphological characteristics. The search strategy was conducted in major electronic databases. Two reviewers worked independently to screen all possible references via a title/abstract examination. Methodological quality was examined with the Anatomical Quality Assurance checklist. A total of 295 cadaveric knees were included in the nine studies where in 244 (82.7%) cases the TVI was identified. Based on this evidence, it appears that the TVI is located between the vastus lateralis and vastus intermedius. The muscle belly is located proximally, and it is combined with a broad and flat aponeurosis before forming a tendinous structure that is attached at the medial aspect of the patella. The TVI presented some morphological variations and complex muscle architecture that varied along its length. There is insufficient good quality evidence as more than half of the included studies were ranked as having a “High” risk of bias with various methodological issues. Higher quality studies are recommended to evaluate the TVI morphology to better understand its functional and clinical importance.

Soccer teams integrate specific exercises into their typical workout programs for injury prevention. The purpose of this study was to investigate whether the incorporation of a brief and supplementary training program that involves eccentric, balance, and core exercises into the weekly soccer schedule can cause positive neuromuscular adaptations. Twenty-one soccer players were randomly allocated to either a training (n = 11) or a control group (n = 10). All players followed their teams’ typical program, consisting of 4–5 soccer-specific sessions plus 1 match, weekly. Training group players additionally performed biweekly, hamstring eccentric, balance, and core stability exercises for 8 weeks. Isokinetic concentric and eccentric peak torque (PT) of the hamstrings and quadriceps, changes in the center of pressure (COP) during a 30 s single-leg stance, and a supine bridge (trunk stability) test were assessed before and after the intervention. After the intervention, a 27% increase in hamstring concentric PT and a 33% reduction in COP sway in the stance test, were observed for the training group only (p &lt, 0.05). These improvements were significant only for the non-dominant leg. Furthermore, the control group displayed an increase in COP sway during the bridge test compared to baseline values (p &lt, 0.05), which reflects a deterioration in postural balance over time. Consequently, incorporating small doses of hamstring eccentric, proprioception, and core stability exercises into a typical training program of youth soccer players improves strength and postural balance in the non-dominant leg, as well as core muscle performance.

Exercises for lumbar multifidus (LM) muscle are important for injury and low back pain prevention and treatment. This study examined the differences in LM contraction thickness between variations of the superman and bird dog exercises. Twenty-one recreational athletes performed the superman exercise from the prone position with the following grading: rest, right upper extremity lift (RU), right lower extremity (RL) and upper and lower extremities lift (UL). They also performed the following bird dog variations from the quadruped position: rest, RU, RL and left upper - right lower extremity lift (LURL). LM muscle thickness of both sides was recorded using two ultrasonography (US) devices. LM thickness during superman-UL, was significantly greater compared with the other exercises and significantly lower during upper extremity exercises compared with lower extremity exercises (p < 0.05). No significant differences in LM thickness between sides was found (p > 0.05). The US measurements of LM thickness displayed good to excellent intrarrater reliability for both muscle sides. It appears that superman-UL is the most effective exercise for a greater contraction thickness of LM. Further, in order to progressively increase LM muscle thickness, upper extremity tasks should be performed prior to lower extremity tasks and combined upper and lower lifting tasks.

The purpose of the study was to evaluate the influence of changes in ankle- and knee-joint angles on force steadiness and the discharge characteristics of motor units (MU) in soleus when the plantar flexors performed steady isometric contractions. Submaximal contractions (5, 10, 20, and 40% of maximum) were performed at two ankle angles (75° and 105°) and two knee angles (120° and 180°) by 14 young adults. The coefficient of variation of force decreased as the target force increased from 5 to 20% of maximal force, then remained unaltered at 40%. Independently of knee angle, the coefficient of variation for force at the ankle angle of 75° (long length) was always less (p

The objective of this study was to investigate the reliability of distal hamstring tendon morphology using freehand 3-D ultrasound (US). Freehand 3-D US scans were acquired for 16 young males and females, in two sessions, spaced a week apart. The length, volume, cross-sectional area (CSA) and echo intensity (EI) of the semitendinosus (ST), biceps femoris long and short head and semimembranosus (SM) tendons were acquired. Measurements of the CSA and EI were obtained from three sites along each tendon. The intra-class correlation coefficients ranged from 0.88-0.99 of the examined variables, indicating high test-retest reliability. In addition, the minimal detectable change (MDC) ranged from 0.255-3.766 mm (MDC% of the mean: 0.406%-12.558%) for hamstring tendon length, from 0.036-0.077 mL (MDC%: 1.548%-3.178%) for tendon volume, from 0.512-1.948 mm2 (MDC%: 0.702%-3.586%) for CSA and from 0.898-2.586 au (MDC%: 1.145%-3.325%) for EI. Of the four hamstring tendons, ST had the greatest length (141.587 ± 10.701 mm) and EI (94.637 ± 5.536 au), while SM had the greatest volume (3.056 ± 0.421 mL) and CSA (115.277 ± 16.442 mm2) relative to other tendons. Freehand 3-D US appears to be a reliable tool for the evaluation of hamstring distal tendon morphology; hence, its use for in vivo evaluation of tendon properties is promising.

This study examined whether the association between hamstring (H) and quadriceps (Q) strength with size depends on the region and the muscle used to examined cross-sectional area (CSA). Maximum isometric contraction knee extension and flexion torque was obtained from 20 young participants while Q and H CSA was recorded using extended field of view ultrasonography at four sections along the thigh. Stepwise linear regression models using the maximum CSA of individual muscles showed a significant association of quadriceps (R

Exercise responses and injury rates differ between individual hamstrings and this may be linked with their morphology. The aim of this study was to compare muscle length and tendon dimensions between the individual hamstrings at two knee joint angles using free hand three-dimensional ultrasound (3D US). Muscle-tendon length and distal tendon cross-sectional area (CSA), volume, length and echogenicity of biceps femoris long (BFlh) and short (BFsh) head, semimembranosus (SM) and semitendinosus (ST) of 16 individuals were measured using free-hand 3D US at 0° (full extension) and 45° of knee flexion. ST showed the greatest length than all muscles and BFsh the lowest (p 0.05). No difference was observed between SM and BFlh length (p 0.05). Of the four muscles, ST tendon was longer, with less volume and CSA but greater echogenicity than the other tendons. In contrast, SM and BFlh showed shorter tendons and lower echogenicity but a greater volume and CSA than ST (p 0.05). Muscle and tendon lengthened from 45° to 0° knee flexion angle (p 0.05) but this change was not statistically different between individual hamstrings (p 0.05). Freehand 3D US indicated that hamstring muscle length and distal tendon dimensions differ between individual hamstrings. All muscles and tendons lengthened as the knee was extended but this change was similar for all individual hamstrings.

BACKGROUND Following ankle sprain, residual symptoms are often apparent, and proprioceptive training is a treatment approach. Evidence, however, is limited and the optimal program has to be identified. OBJECTIVE To investigate the effects of two post-acute supervised proprioceptive training programs in individuals with ankle sprain. METHODS Participants were recruited from a physiotherapy center for ankle sprain rehabilitation. In a pre-post treatment, blinded-assessor design, 22 individuals were randomly allocated to a balance or a proprioceptive neuromuscular facilitation (PNF) group. Both groups received 10 rehabilitation sessions, within a six-week period. Dorsiflexion range of motion (ROM), pain, functional and balance performance were assessed at baseline, at the end of training and eight weeks after training. RESULTS Follow-up data were provided for 20 individuals. Eight weeks after training, statistically significant (p< 0.017) improvements were found in dorsiflexion ROM and most functional performance measures for both balance and PNF groups. Eight weeks after training, significant (p< 0.017) improvements in the frontal plane balance test and pain were observed for the balance group. CONCLUSIONS Balance and PNF programs are recommended in clinical practice for improving ankle ROM and functional performance in individuals with sprain. Balance programs are also recommended for pain relief.

Analysis of plantar pressure during sport movement performance can provide significant information to athletes and coaches regarding sport performance and plantar loads. In tennis, the serve is one of the most difficult and most important strokes. The purpose of this study was to examine the plantar pressure differences between the flat, slice and topspin serves with the “foot back” serving technique on greenest tennis surfaces of junior athletes aged 10 to 16. The results showed that the loads were higher on the rear (right) back foot of all the three serves. The Fmax was higher in foot toes for all types of serve and the peak pressure was higher in slice serve in the metatarsal forefoot region of the back right foot. The results showed that the technique applied, mainly to the footwork, varies between types of serves. So, each type of the three serves has different loads.

Bridging exercises with abdominal hollowing are often used as a regimen for improving spinal stability. Lately, this type of training has become very popular among elite athletes, creating a need for more demanding exercises. The purpose of this study was to investigate whether the use of additional external resistance is beneficial for abdominal muscle recruitment during bridge exercise. Tissue movement of the transversus abdominis (TrA) and the rectus abdominis (RA) was recorded with the use of two synchronized ultrasonic devices, in 20 healthy college students. From the hook-lying position participants were examined in eight different exercise conditions: a) rest, b) abdominal drawing-in maneuver (ADIM), c) bridge, d) bridge- ADIM, e) bridge with 10KG, f) bridge- ADIM with 10KG, g) bridge with 20KG and h) bridge-ADIM with 20KG. Analysis of variance (ANOVA) showed a statistically significant increase in TrA thickness when performing the bridge exercise combined with ADIM compared to rest mode (p < .05). RA thickness decreased when the ADIM was performed, compared to rest (p < 0.05). No significant difference in TrA and RA thickness when exercising with and without external resistance was observed (p > 0.05). The main outcome of this study was that external loading provided some extra level of difficulty, yet it was not beneficial for abdominal muscle recruitment, when performing a supine bridge exercise.

The aim of this study was to investigate whether the application of the integrated neuromuscular inhibition technique (INIT) combined with therapeutic exercise (TE) can provide faster and greater improvement in maximum isometric strength and isometric endurance of the neck muscles in patients with chronic mechanical neck pain (CMNP).In this 10-week, single-blind clinical trial, 40 participants (men and women) with CMNP were divided into two groups. The intervention group (IG) followed a TE program in combination with the INIT, while the control group (CG) followed the same TE program without the INIT technique. Changes in maximum isometric strength and isometric endurance of the neck muscles were evaluated before, during, and after the intervention, with follow-up measurements taken at 1, 3, and 6 months after the intervention. Analysis of variance with repeated measures was applied.Both groups showed a significant improvement in all dependent measures after the intervention (p .05). These changes were maintained for both groups 6 months after the intervention. However, the IG showed a greater improvement in the maximum isometric strength of neck flexion and an improved craniocervical flexion test score compared with the CG.The combination of TE and INIT had a positive effect on neck muscle strength and endurance in individuals suffering from CMNP as compared with TE alone.

The purpose of this study was to examine parental perceptions about Health Related Quality of Life (HRQoL) of typical education and special education students in Greece. The Pediatric Quality of Life Inventory (PedsQL) was administered to the parents of 251 children from typical schools, 46 students attending integration classes (IC) within a typical school and 97 students attending special education (segregated) schools. A two-way analysis of covariance indicated that, compared to their typically developing peers, children attending special education schools and IC were reported by their parents to have lower PedsQL scores. Compared to children attending special education schools, children attending IC showed no differences in all PedsQL domains but the emotional domain score (p

This study examined the use of ultrasound to monitor changes in the long head of the biceps femoris (BF) architecture of aprofessional soccer player with acute first-time hamstring strain. The player followed a 14 session physiotherapy treatment until return to sport. The pennation angle and aponeurosis strain of the long head of the biceps femoris (BF) were monitored at 6 occasions (up until 1 year) after injury. The size of the scar / hematoma was reduced by 63.56% (length) and 67.9% (width) after the intervention and it was almost non-traceable one year after injury. The pennation angle of the fascicles underneath the scar showed a decline of 51.4% at the end of the intervention while an increase of 109.2% of the fascicles which were closer to deep aponeurosis was observed. In contrast, pennation angle of fascicles located away from the injury site were relatively unaffected. The treatment intervention resulted in a 57.9% to 77.3% decline of maximum strain per unit of MVC moment and remained similar one year after the intervention. This study provided an example of the potential use of ultrasound-based parameters to link the mechanical adaptations of the injured muscle to specific therapeutic intervention.

Aim: The purpose of the present study was to establish which type of exercise is optimal for Rectus Abdominis (RA) muscle, by measuring thickness and length changes using the extended field of view ultrasonography (EFOV US) during different conditions. The second purpose was to estimate the reliability of EFOV US as a muscle morphology assessment tool.Material and methods: Segmental muscle thickness and length of 11 young healthy adults was assessed during 1) rest and isometric 2) trunk lifting, 3) leg lifting and 4) combined trunk and leg lifting exercises with the use of EFOV US.Results: RA muscle thickness was significantly greater during exercises compared to rest (p0.05). Further, EFOV US displayed excellent reliability as the ICC values ranged from 0.82 to 0.97.Conclusions: According to our observations it seems that exercises that induce lifting of the legs might be more effective for the distal parts of RA muscle. EFOV appears to be a reliable diagnostic tool for measuring RA muscle thickness during rest and contracting states.

Aim: Τo examine the inter- and intra-muscular differences in the anatomical cross-sectional area (CSA) of the quadricep muscles, using extended - field of view (EFOV) ultrasonography (US).Material and methods: Panoramic transverse US images of the thigh were acquired from 10 young participants at five different locations across the thigh, in two sessions, spaced a week apart. The CSA of the vastus medialis (VM), rectus femoris (RF), vastus intermedius (VI), vastus lateralis (VL) and tensor vastus intermedius (TVI) was quantified.Results: The intraclass correlation coefficients ranged from 0.75 to 0.97 and the standard error of measurement ranged from 0.78% to 6.61%, indicating high test-retest reliability. Analysis of the variance indicated that among the 5 quadriceps muscles the VL and the RF displayed the greater CSA proximally, the VI medially and the VM distally across the thigh (p 0.05).Conclusions: The EFOV US technique provides transverse scans of the quadriceps muscle in vivo and allowed a reliable and non-invasive determination of CSA at a low cost. Evaluation of CSA along the thigh largely depends on the measurement site. Future studies that examine the quadriceps CSA using EFOV after any form of intervention should consider changes of at least 6.5% as meaningful.

Understanding the architecture, anatomy, and biomechanics of the hamstrings may assist in explaining the mechanisms that affect and improve their function. The aim of this review is to specifically examine intra- and inter-muscular variations in architecture and mechanical properties of the hamstrings. Of the hamstrings, the long head of the biceps femoris shows the shortest and more pennated fibers. The semimembranosus has a similar muscle architecture with a long head of the biceps femoris but it has a different proximal attachment as well as a different moment arm compared with the long head of the biceps femoris. For the same joint motion, the semitendinosus displays less relative strain than the other hamstrings probably owing to a greater length, longer fascicles and, possibly, a longer tendon. Intra-muscular variations in architecture are documented but their implications are currently unclear. Proximally, the long head of the biceps femoris has shorter and more pennated fibers coupled with a narrower aponeurosis than distally, while the semitendinosus is the only muscle that entails a tendinous inscription. In conclusion, some of the identified intra- and inter-muscular variations in architecture may help explain why some muscles sustain injuries more than others. In the same line, exercises designed for the hamstrings may not provide the same stimulus for all components of this muscle group. Future research could examine whether intervention strategies that target specific muscles or specific areas of the hamstrings may offer additional benefits for injury prevention or rehabilitation of their function.