Effects of foam rolling on vastus intermedius and lateralis microvascular blood flow.

INTRODUCTION: Foam Rolling (FR) as a technique of self-massage has become a widely used intervention in clinical and sports practice. It is assumed that FR leads to an increased intramuscular microvascular blood flow (MBF), and therefore is commonly recommended as a warm-up or regeneration method. However, no data validate the effects of FR on MBF. This study aimed to assess whether FR increases intramuscular MBF using contrast-enhanced ultrasound (CEUS). METHODS: Ten healthy athletes performed a standardized FR intervention applied to the lateral thigh (3 sets: 45 s FR, 20 s rest). Intramuscular perfusion was determined by CEUS under resting conditions (t0), immediately (t1), and 30 min (t2) after the intervention. Peak enhancement (PE), wash-in rate (WiR), and wash-in perfusion index (WiPI) were evaluated as quantitative perfusion parameters in vastus lateralis (VL) and intermedius (VI) muscle separately via regions of interest mapping. RESULTS: Immediately after the intervention (t1), perfusion parameters showed a non-significant decrease in VL (p = 0.3; PE: -32.1%, WiPI: -29.6%, WiR: -50.4%) and VI (p = 0.4; PE: -10.3%, WiPI: -6.4%, WiR: -35.6%). A non-significant decrease was found at t2 in VL (p = 0.2; PE: -34%, WiPI -33.9%, WiR -61.2%) and VI (p = 0.2; PE -17.6%, WiPI -13.8%, WiR -43.2%). CONCLUSIONS: The common assumption of intramuscular MBF improvement due to FR could not be confirmed for up to 30 min after the intervention. If an increase in intramuscular metabolism or MBF is intended, we recommend that alternative methods (i.e., traditional warm-up) should be preferred.

Who runs the fastest? Anthropometric and physiological correlates of 20 m sprint performance in male soccer players.

The aim of the present study was to examine the relationship of 20 m sprint performance with anthropometrical and physiological parameters in male soccer players. A hundred and 81 soccer players from the region of Athens (age 23.4 ± 5.0 yrs, body mass 73.4 ± 7.7 kg, height 180.0 ± 5.9 cm, body fat (BF) 14.4 ± 3.6%), classified into quartiles according to 20 m sprint time (group A, 2.84-3.03 s; group B, 3.04-3.09 s; group C, 3.10-3.18 s; group D, 3.19-3.61 s), participated. Soccer players in group A were younger and had better performance in vertical jumps and in the Wingate anaerobic test (WAnT, p < 0.05). Sprint time correlated to age (r = 0.27), body mass (r = 0.23), body height (r = 0.20), BF (r = 0.23), vertical jumps (-0.58 ≤ r ≤ -0.50) and the WAnT (-0.45 ≤ r ≤ -0.30, p < 0.05). In summary, the magnitude of correlations of sprint time with measures of lower limbs muscle strength and power (WAnT and jumps) was larger than with anthropometric measures (body mass and BF).

Genetic diversity affects the strength of population regulation in a marine fish.

Variation is an essential feature of biological populations, yet much of ecological theory treats individuals as though they are identical. This simplifying assumption is often justified by the perception that variation among individuals does not have significant effects on the dynamics of whole populations. However, this perception may be skewed by a historic focus on studying single populations. A true evaluation of the extent to which among-individual variation affects the dynamics of populations requires the study of multiple populations. In this study, we examined variation in the dynamics of populations of a live-bearing, marine fish (black surfperch; Embiotoca jacksoni). In collaboration with an organization of citizen scientists (Reef Check California), we were able to examine the dynamics of eight populations that were distributed throughout approximately 700 km of coastline, a distance that encompasses much of this species' range. We hypothesized that genetic variation within a local population would be related to the intensity of competition and to the strength of population regulation. To test this hypothesis, we examined whether genetic diversity (measured by the diversity of mitochondrial DNA haplotypes) was related to the strength of population regulation. Low-diversity populations experienced strong density dependence in population growth rates and population sizes were regulated much more tightly than they were in high-diversity populations. Mechanisms that contributed to this pattern include links between genetic diversity, habitat use, and spatial crowding. On average, low-diversity populations used less of the available habitat and exhibited greater spatial clustering (and more intense competition) for a given level of density (measured at the scale of the reef). Although the populations we studied also varied with respect to exogenous characteristics (habitat complexity, densities of predators, and interspecific competitors), none of these characteristics was significantly related to the strength of population regulation. In contrast, an endogenous characteristic of the population (genetic diversity) explained 77% of the variation in the strength of population regulation (95% CI: 27-94%). Our results suggest that the genetic and phenotypic composition of populations can play a major role in their dynamics.

Match Running Performance and Success Across a Season in German Bundesliga Soccer Teams.

The aim of the study was to quantify the association between match running performance and success across a season in soccer teams competing within a European top league. We analyzed the match running performance data of all soccer teams from the German Bundesliga across the season 2012/13 (306 matches). The following match running performance data were used: total distance covered as well as number of running activities>18.0 km/h and > 22.7 km/h. Depending on the team's ball possession status, all match running performance data were also analyzed as those with and without ball possession. The success across the season was defined as the final competition points accumulated. The match running performance alone was not significantly correlated with the final points accumulated (best r=0.24; p=0.34). In contrast, positive-significant correlations were observed for the match running performance with ball possession (best r=0.77; p<0.01). However, of these latter correlations, only the total distance covered with ball possession was a significant predictor (p<0.01) and accounted for 60% of the variance (R(2)=0.60) in the final points accumulated. It is concluded that it is not the match running performance alone that is important for achieving success in German Bundesliga soccer teams, but rather its relation to technical/tactical skills with respect to ball possession.

[Reliability of Selected Parameters of Cycling Ergospirometry from the PowerCube-Ergo Respiratory Gas Analyser]. / Reliabilität ausgewählter Parameter der Fahrradergospirometrie anhand des PowerCube-Ergo-Atemgasanalysators.

This study aimed to investigate the reliability of 1) the key parameters of cycling ergospirometry (maximum power output [Pmax] and oxygen uptake [V̇O2peak], ventilatory thresholds 1 [VT 1] and 2 [VT 2], and cycling efficiency [CE] and gross efficiency [GE]), 2) the commonly used parameters to quantify exhaustion (maximum heart rate [HFmax], respiratory quotient [RQmax], blood lactate concentration [BLAmax], and ratings of perceived exhaustion [RPEmax]), and 3) the kinetics of exercise induced gas exchange measurements (oxygen uptake [V̇O2], carbon dioxide output [V̇CO2], and minute ventilation [V̇E]) using the PowerCube-Ergo metabolic system in consideration of international statistical recommendations. 12 women and 12 men (28 ±â€Š4 years; 23.2 ±â€Š2.4 kg/m(2)) performed two cycling tests (20 watt/min) separated by one week. The reliability was calculated based on differences in means (t test and effect sizes), retest correlation (intraclass correlation coefficient [ICC]), and within-subject variation (standard error of measurement [SEM]). Of the key parameters of cycling ergospirometry, an excellent reliability (ICC ≥ 0.969; p = 0.000) and high accuracy (%SEM ≤ 4.6) were found for Pmax, V̇O2peak, and VT 1. Of the most commonly used parameters to quantify exhaustion, an excellent reliability (ICC = 0.922; p = 0.000) and high accuracy (%SEM = 1.0) existed only for HFmax. The gas exchange measurements (V̇O2, V̇CO2 und V̇E) of the PowerCube-Ergo were all excellently reliable (ICC ≥ 0,991; p = 0.000) and the accuracy of V̇O2 (SEM = 0.10 l/min) and V̇E (SEM = 3.13 l/min) fulfilled the quality guidance of exercise physiology laboratories. For future studies and practical purposes, the results are vital for the decision as to whether a difference between two tests represents a true intervention effect or just a measurement error and for the estimation of required sample sizes.

Relationship between core strength and key variables of performance in elite rink hockey players.

AIM: The aim of this study was to test the hypothesis that a significant relationship exists between the level of core strength-endurance and key variables of endurance, strength, power, speed, and agility performance in male elite rink hockey players. METHODS: Ten male elite rink hockey players of the German national team were tested for 1) time to exhaustion, maximum oxygen uptake, and running economy, 2) one repetition maximum bench press and half squat, 3) counter movement jump height, 4) 5 m, 10 m, and 20 m speed, and 5) 22 m agility. The rink hockey players were also tested for 6) ventral, lateral-left, lateral-right, and dorsal core strength-endurance using concentric-eccentric muscle tests. RESULTS: The level of total and ventral core strength-endurance was very largely correlated with maximum oxygen uptake (r=0.74 and r=0.71, both P<0.05). Additionally, there was a large correlation between the level of ventral core strength-endurance and time to exhaustion (r=0.66, P<0.05). No further significant relationships were observed (best r=0.60, P>0.05). CONCLUSION: The findings from this study suggest that the level of core strength-endurance is largely to very largely correlated with key variables of endurance performance, but not significantly with strength, power, speed, or agility indicators in male elite rink hockey players. These findings should be noted by coaches and scientists when testing physical fitness or planning strength and conditioning programs for male elite rink hockey players.

Different endurance characteristics of female and male german soccer players.

The aims of the present study were to assess gender differences regarding lactate threshold and intermittent shuttle run performance in female and male soccer players as well as to investigate the relationships between both endurance characteristics in both genders. Fourteen female (1(st) division) and thirteen male (4(th) division) soccer players completed an incremental test (IT) to determine running velocities at 2 and 4 mmol · l(-1) blood lactate (v2 and v4) and maximum velocity (vmax) as well as an interval shuttle run test (ISRT) to determine running distance. Based on v2 and v4 and their percentages in relation to vmax, three intensity zones were calculated: a low lactate zone (v4). Female soccer players have a lower v4 (8.2%), vmax (11.3%) and ISRT distance (31.6%). No gender difference was found in v2. In contrast to males, ISRT distance correlates with vmax as well as with v2 and v4 in female soccer players. The intensity zones v4 differ between genders. The present study revealed that gender differences increase when the running performance is intermittent including change of directions. In both genders, different relationships between lactate threshold and intermittent shuttle run performance exist. During incremental testing, the running performances of female and male players reflect different distributions of aerobic and anaerobic metabolic pathways. The revealed gender differences should be considered for soccer endurance training.

[Adaptive mechanisms and behavioural recommendations: playing football in heat, cold and high altitude conditions]. / Hitze, Kälte und Höhenexposition im Fußball: Adaptive Mechanismen und Verhaltensstrategien in variierenden Umweltbedingungen.

Football is played worldwide and players often have to cope with hot and cold temperatures as well as high altitude conditions. The upcoming and past world championships in Brazil, Qatar and South Africa illustrate the necessity for behavioural strategies and adaptation to extreme environmental conditions. When playing football in the heat or cold, special clothing, hydration and nutritional and acclimatisation strategies are vital for high-level performance. When playing at high altitude, the reduced oxygen partial pressure impairs endurance performance and alters the technical and tactical requirements. Special high-altitude adaptation and preparation strategies are essential for football teams based at sea-level in order to perform well and compete successfully. Therefore, the aim of the underlying review is: 1) to highlight the difficulties and needs of football teams competing in extreme environmental conditions, 2) to summarise the thermoregulatory, physiological, neuronal and psychological mechanism, and 3) to provide recommendations for coping with extreme environmental conditions in order to perform at a high level when playing football in the heat, cold and at high altitude.

[Restoration of active foot extension following peroneal nerve palsy]. / Obnova aktivní extenze nohy pri paréze peroneálních nervu.

INTRODUCTION: Common peroneal nerve palsy is the commonest lower extremity peripheral paresis. The foot drop and inability or difficulty to move the ankle and toes dorsally and inability to perform foot pronation is a debilitating condition for the patient. Tendon transfer is a treatment option often used to restore the foot function after the peroneal palsy in cases when reinervation is not clinically satisfactory. MATERIAL AND METHODS: The study group included 14 patients treated in the Trauma department of FNO either for common or deep peroneal nerve paresis, or for isolated lesion of the anterior tibial muscle. Active muscles, i.e.the posterior tibial muscle (13 patients) or long peroneal muscle (1 patient) were used for the movement restoration procedure. The tendons were anchored to the cuneiform bone. RESULTS: In all the patients, active foot extension was restored, with the average range of motion of 12.3 degrees (4-20) and with sufficient muscle strength. Based on the Stanmore score assessment, the subjects showed good results, reaching 87-100 points. CONCLUSION: The posterior tibial muscle tendon transfer, or peroneus longus muscle tendon transfer lead to restoration of active extension of the foot. The reconstruction procedure results in a minor restriction of the ankle range of motion. Considering the foot functionality, it is better to perform the transfer with a slight preload of the tendon, in order to achieve adequate postoperative ankle extension.

Differences in hamstring muscle stretching of elite field hockey players and normal subjects.

OBJECTIVES: To investigate differences in stretching behaviour of hamstring muscles in elite field hockey players and normal subjects. METHODS: 16 normal healthy subjects (group A) and 16 elite field hockey players (group B). Stretching of the hamstrings was performed with a knee extension device. Two successive single stretches (1 and 2) until the maximum stretch tolerance was achieved were applied to each subject twice. Simultaneously range of movement (ROM), passive resistance to stretch (PRS) at 36 degrees ROM, and electromyographic (EMG) activity of the biceps femoris and semitendinosus muscles were recorded. RESULTS: ROM (p=0.02 for stretch 1; p=0.04 for stretch 2) and PRS (p=0.04 and p=0.03) were significantly higher in group B, as compared to group A. The EMG activity of the biceps femoris (p=0.02 for stretch 1; p=0.3 for stretch 2) and semitendinosus (p=0.03 and p=0.11) were significantly higher in group B only for stretch 1. From stretch 1 to 2, a significant increase in ROM was observed in both group A (p=0.002) and group B (p=0.0003), as well as a significant decrease of PRS (p=0.0002; p=0.002). EMG activity only showed a significant decrease in group B (biceps p=0.03;semitendinosus p=0.01), but not in group A (p=0.6; p=0.06). The EMG activity sets in when the subjects begin to perceptive pain in the stretched muscles. CONCLUSIONS: Significant differences exist. in the stretching behaviour of elite field hockey players and non-athletes. ROM, PRS and EMG activity are higher in athletes. Implications for treatment should be considered, but recommendations cannot be made on the basis of this study yet.

[Current concepts in the diagnosis and rehabilitation of the shoulder in overhead athletes]. / Uberlegungen zur Diagnostik und Rehabilitation des Schultergelenkes bei Uberkopfsportlern.

The purpose of this paper is to present the general guidelines, including implementation of principles of motor learning in the course of the rehabilitation of the shoulder in overhead athletes. The focus is on treating the most common injury pattern of overhead athletes being rotator cuff pathology with secondary bursitis and finally microtraumatic instability. Specific criteria are discussed to determine when the athlete can return to unrestricted sport participation.

[Rehabilitation after anterior cruciate ligament reconstruction]. / Rehabilitation nach vorderer Kreuzbandplastik.

The "Frankfurt rehabilitation regimen" following anterior cruciate ligament reconstruction is presented. ACL rehabilitation is discussed in the light of knowledge on knee biomechanics and proprioception as well as clinical results of reconstruction. Special emphasis is given to exercise therapy.

[Stretching--do current explanatory models suffice?]. / Dehnung--genügen die bisherigen Erklärungsmodelle?

The opinion that mobility in the usual performance if the "straight leg raise" test for the evaluation of stretching techniques is subject to solety muscular limitations is critically appraised. With integration of recent results from molecular biological research and our own measurements, we can show that not only mechanical but also neurophysiological factors must be considered in the limitation of mobility. In the majority of the examined patients stretching of the ischiadic nerve seems to be responsible for restrictions in movement. The presented results cast doubt on the currently held assumptions and basic principles of stretching in therapy and sport.

[Stretching--possibilities and limits]. / Dehnen--Möglichkeiten und Grenzen.

The basic scientific knowledge about stretching remains incomplete in spite of its wide use in sports and physiotherapy. This article deals with the assessment of the flexibility and with the anatomical and physiological basis and limitations of stretching. The effects of stretching on delayed onset muscle soreness (DOMS), performance and regeneration are discussed. Recommendations are given for stretching as a measure of warming-up and cooling-down, for stretching before exercises, which demand explosive maximum muscle strength, and for stretching after training for strength endurance.

[The nerve supply of the knee joint]. / Die nervöse Versorgung der Kniegelenke.

The paper presents the present state of research on the most important receptors of joints and muscles with regard to occurrence, structure, and function. Proprioception relies on the nervous supply of the tissues in the knee joint, and on the surrounding muscles and tendons; it is the basis of coordination.

[Indications and surgical procedures in meniscus and capsular ligament injuries]. / Indikation und operative Verfahren bei Meniskus- und Kapselbandverletzungen.

The main aim in the treatment of meniscus injuries is the restoration of the meniscus by a primary suture. Partial resections of the meniscus should be done in a sophisticated arthroscopic technique. By the reason of relaxing of the joint's ligament should be repaired by operation. In spite of a larger "defect" bone-tendon-bone techniques are to prefer because of an improved long-term stability.

[Therapeutic physical training after knee injuries]. / Trainingstherapeutische Behandlung nach Knietraumen.

Exercise training is a therapy that accompanies and follows physiotherapy. Basic training principles are discussed on the basis of motricity research. Initially, exercise therapy mostly trains patients to recall and standardize the execution of exercise programs. With the patient's increasing power of endurance, the intensity of extent of training are increased. Exercise therapy eventually aims at particularly preparing the patient for the activities of daily living and the sportsman for the requirements specific to training and competition.

[Treatment with physical therapy after knee injuries]. / Physiotherapeutische Behandlung nach Knietraumen.

Trauma to the inner knee disturb the organism's local and central regulations. Physiotherapeutic measures stimulate self-regulatory and self-regenerative mechanisms of the organism. Depending on the specific needs of the patient, active exercise treatment, or various procedures of physical therapy are administered (hydro and thermotherapy, electromedicine, light therapy, aerosol therapy, balneology, and climatology) in order to achieve his/her full restoration to the maximal potential vocationally, socially, and physically.

Spondylolysis and spondylolisthesis: correlation with sport.

Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.

[Spondylolysis and spondylolisthesis and sports]. / Spondylolyse und Spondylolisthesis und Sport.

Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.