{"title":"Acute Effect of Active and Passive Static Stretching on Elastic Modulus of the Hamstrings.","authors":"Gakuto Nakao, Keigo Taniguchi, Masaki Katayose","doi":"10.1055/a-0733-6957","DOIUrl":"https://doi.org/10.1055/a-0733-6957","url":null,"abstract":"<p><p>The purpose of this study was to investigate differences in the acute effects of passive knee extension (PKE) and active knee extension (AKE) stretching on the shear elastic modulus of the hamstrings. In 20 healthy men, maximum knee extension (maximum range of motion [ROM]) and shear elastic modulus of the hamstrings (biceps femoris long head, semitendinosus, semimembranosus) were measured before (Pre) and after (Post) AKE and PKE stretching. The maximum ROM during stretching was measured. In both stretching methods, maximum ROM increased and the shear elastic modulus decreased (p<0.01), but no difference was found between the procedures. No significant difference was observed in the maximum ROM during stretching between the procedures (p=0.06). The shear elastic modulus was significantly lower in the biceps femoris long head and semimembranosus than in the semitendinosus muscle (p<0.05). Static stretching with PKE and AKE stretching showed an increase in maximum ROM and a decrease in hamstring elasticity, but no difference was found between the methods. Both stretching protocols were effective for reducing elasticity of the biceps femoris long head and semimembranosus.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 6","pages":"E163-E170"},"PeriodicalIF":0.0,"publicationDate":"2018-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1055/a-0733-6957","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36773112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Irene González-González, David Rodríguez-Rosell, David Clavero-Martín, Ricardo Mora-Custodio, Fernando Pareja-Blanco, Juan Manuel Yáñez García, Juan José González-Badillo
{"title":"Reliability and Accuracy of Ball Speed During Different Strokes in Young Tennis Players.","authors":"Irene González-González, David Rodríguez-Rosell, David Clavero-Martín, Ricardo Mora-Custodio, Fernando Pareja-Blanco, Juan Manuel Yáñez García, Juan José González-Badillo","doi":"10.1055/a-0662-5375","DOIUrl":"10.1055/a-0662-5375","url":null,"abstract":"<p><p>This study aimed to examine the relationship between anthropometric and sport level (SL) variables and both ball speed and accuracy in young male competitive tennis players. A secondary aim of this study was to analyze the possible differences in ball speed and accuracy between players of different competitive levels. A total of 85 players (age: 14.7±2.4 years; height: 1.65±0.12 m; body weight: 56.3±13.4 kg) were divided into five groups according to their positions in the ranking list. To measure stroke performances, the goal was to hit 20 balls at the maximum possible speed inside the court, with the opportunity of hitting a maximum of 30 balls for each groundstroke and 40 for serve. Accuracy was calculated by dividing the number of balls inside the default surface by the total number of hits. The ball speed showed high reliability for all three strokes assessed. The ball speed progressively increased as SL increased for all strokes, whereas accuracy remained unchanged across SL groups. All independent variables presented significant relationships (r=0.59-0.85, p<0.05-0.001) with ball speed for all strokes. However, after applying partial correlations these relationships decreased substantially (r=0.02-0.51). The accuracy showed significant relationships with SL only in the serve (r=0.31, p<0.05) and backhand (r=0.26, p<0.05) strokes. In conclusion, the results of the present study suggest that tennis performance depends on increasing ball speed while maintaining a relatively stable level of accuracy.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 5","pages":"E133-E141"},"PeriodicalIF":0.0,"publicationDate":"2018-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/d9/c5/10-1055-a-0662-5375.PMC6259460.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36773108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Static Stretching with Superficial Cooling on Muscle Stiffness.","authors":"Masatoshi Nakamura, Ryo Hirabayashi, Shuhei Ohya, Takafumi Aoki, Daichi Suzuki, Mitsuki Shimamoto, Takanori Kikumoto, Wataru Ito, Emi Nakamura, Tomoya Takabayashi, Mtsuaki Edama","doi":"10.1055/a-0684-9375","DOIUrl":"https://doi.org/10.1055/a-0684-9375","url":null,"abstract":"<p><p>This study aimed to clarify the acute effect of static stretching (SS) with superficial cooling on dorsiflexion range of motion (DF ROM) and muscle stiffness. Sixteen healthy males participated in the cooling condition and a control condition in a random order. The DF ROM and the shear elastic modulus of medial gastrocnemius (MG) in the dominant leg were measured during passive dorsiflexion. All measurements were performed prior to (PRE) and immediately after 20 min of cooling or rested for 20 min (POST), followed by 2 min SS (POST SS). In cooling condition, DF ROM at POST and POST SS were significantly higher than that at PRE and DF ROM at POST SS was significantly higher than that at POST. In addition, the shear elastic modulus at POST was significantly higher than that at PRE and the shear elastic modulus at POST SS was significantly lower than those at PRE and POST. However, there were no significant differences in the percentage changes between PRE and POST SS between the cooling and control conditions. Our results showed that effects of SS with superficial cooling on increases in ROM and decrease in muscle stiffness were no more beneficial than those of SS alone.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 5","pages":"E142-E147"},"PeriodicalIF":0.0,"publicationDate":"2018-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1055/a-0684-9375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36773109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cyril Brechbuhl, Franck Brocherie, Gregoire P Millet, Laurent Schmitt
{"title":"Effects of Repeated-Sprint Training in Hypoxia on Tennis-Specific Performance in Well-Trained Players.","authors":"Cyril Brechbuhl, Franck Brocherie, Gregoire P Millet, Laurent Schmitt","doi":"10.1055/a-0719-4797","DOIUrl":"https://doi.org/10.1055/a-0719-4797","url":null,"abstract":"<p><p>This study examined the physiological, physical and technical responses to repeated-sprint training in normobaric hypoxia [RSH, inspired fraction of oxygen (FiO <sub>2</sub> ) 14.5%] vs. normoxia (RSN, FiO <sub>2</sub> 20.9%). Within 12 days, eighteen well-trained tennis players (RSH, n=9 vs. RSN, n=9) completed five specific repeated-sprint sessions that consisted of four sets of 5 maximal shuttle-run sprints. Testing sessions included repeated-sprint ability and Test to Exhaustion Specific to Tennis (TEST). TEST's maximal duration to exhaustion and time to attain the 'onset of blood lactate accumulation' at 4 mMol.L <sup>-1</sup> (OBLA) improvements were significantly higher in RSH compared to RSN. Change in time to attain OBLA was concomitant with observations similar in time to the second ventilatory threshold. Significant interaction (P=0.003) was found for ball accuracy with greater increase in RSH (+13.8%, P=0.013) vs. RSN (-4.6%, P=0.15). A correlation (r=0.59, P<0.001) was observed between change in ball accuracy and TEST's time to exhaustion. Greater improvement in some tennis-specific physical and technical parameters was observed after only 5 sessions of RSH vs. RSN in well-trained tennis players.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 5","pages":"E123-E132"},"PeriodicalIF":0.0,"publicationDate":"2018-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1055/a-0719-4797","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36773107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Simeon Joel Zürcher, Andrea Quadri, Andreas Huber, Lothar Thomas, Graeme Leonard Close, Saskia Brunner, Patrik Noack, Boris Gojanovic, Susi Kriemler
{"title":"Predictive Factors for Vitamin D Concentrations in Swiss Athletes: A Cross-sectional Study.","authors":"Simeon Joel Zürcher, Andrea Quadri, Andreas Huber, Lothar Thomas, Graeme Leonard Close, Saskia Brunner, Patrik Noack, Boris Gojanovic, Susi Kriemler","doi":"10.1055/a-0669-0791","DOIUrl":"https://doi.org/10.1055/a-0669-0791","url":null,"abstract":"<p><p>Vitamin D concentrations corresponding to 75 nmol/L 25(OH)D have been associated with maintained muscle function, growth and regeneration, optimal bone health and immunology in athletes. The objective of this study was to investigate the prevalence and predictors of insufficient 25(OH)D concentrations in athletes. Six hundred three Swiss athletes were assessed. 25(OH)D was analysed by high-performance liquid chromatography (HPLC). A standardized questionnaire was used to gather information about potential predictors for 25(OH)D concentrations; 50.5% showed insufficient 25(OH)D concentrations. Differences in predicted probability of insufficient 25(OH)D were found for those vitamin D supplemented (42%) versus not supplemented (52%), in those performing indoor (58%) versus outdoor sports (43%), and during the sun-deprived seasons of fall (49%), winter (70%) and spring (57%) compared with summer (17%). Higher BMI z-scores and age were associated with higher 25(OH)D concentrations. In conclusion, insufficient 25(OH)D concentrations were common among athletes especially at a younger age, among those not supplemented, in athletes who trained indoors, and during the sun-deprived seasons. Because the prevalence of insufficient 25(OH)D concentrations in this study was high, regular supplementation in athletes may be indicated, except perhaps during the summer season. Further research is needed to determine which 25(OH)D concentrations lead to optimal health and performance in athletes.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 5","pages":"E148-E156"},"PeriodicalIF":0.0,"publicationDate":"2018-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1055/a-0669-0791","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36773110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Robert Nilsson, Ann-Sofie Lindberg, Apostolos Theos, Richard A Ferguson, Christer Malm
{"title":"Aerobic Variables for Prediction of Alpine Skiing Performance - A Novel Approach.","authors":"Robert Nilsson, Ann-Sofie Lindberg, Apostolos Theos, Richard A Ferguson, Christer Malm","doi":"10.1055/a-0655-7249","DOIUrl":"https://doi.org/10.1055/a-0655-7249","url":null,"abstract":"<p><p>The aim of this study was to investigate the predictive power of aerobic test results and anthropometric variables on FIS-ranking of junior elite alpine skiers. Results from twenty-three male and female adolescent elite alpine skiers from two seasons were included in the multivariate statistical models. Physical work capacity was determined by V̇O2peak, blood lactate concentration ([HLa]b), and heart rate (HR) during ergometer cycling. Anthropometric variables were body stature, body weight and calculated BMI. No significant correlation between competitive performance and aerobic work capacity or anthropometric data was observed neither in male nor female adolescent skiers. Pre-season physical tests and anthropometric data could therefore not predict end-season FIS-ranking. The best regression (R2) and prediction (Q2) models of FIS slalom (SL) and giant slalom (GS) rank reached R2=0.51 to 0.86, Q2=-0.73 to 0.18, indicating no valid models. This study could not establish V̇O2peak and other included variables as predictors of competitive performance. When combining results from commonly used tests for alpine skiers, and applying multivariate statistical models, investigated tests seems of limited used for athletes, coaches, and ski federations. Performance-specific pre-season tests must be developed and validated for prediction of performance and guidance of exercise training.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 4","pages":"E105-E112"},"PeriodicalIF":0.0,"publicationDate":"2018-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1055/a-0655-7249","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36816634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Angus Lindsay, Carl Petersen, Hamish Ferguson, Gavin Blackwell, Stephen Rickerby
{"title":"Lack of a Dose Response from 7 Days of Ischemic Preconditioning in Moderately trained Cyclists.","authors":"Angus Lindsay, Carl Petersen, Hamish Ferguson, Gavin Blackwell, Stephen Rickerby","doi":"10.1055/a-0639-5035","DOIUrl":"https://doi.org/10.1055/a-0639-5035","url":null,"abstract":"<p><p>Ischemic preconditioning (IP) has a small benefit on exercise performance, but differences in the IP method, performance tasks and exercise modality have made providing practical coach guidelines difficult. We investigated the performance-enhancing effects of IP on cyclists by comparing the frequency of IP application over a 7-day period. Using a randomized, sham-controlled, single-blinded experiment, 24 competitive age-group track cyclists (38±12 years) were assigned to one of three twice-daily (sham: 20 and 20 mmHg; once-a-day: 20 and 220 mmHg; twice-a-day: 220 and 220 mmHg) IP leg protocols (4 × 5 min ischemia/5 min reperfusion alternating between legs) over seven consecutive days. A 4000-m cycling-ergometer time trial was completed before, immediately following and one week after the protocols. Neither mean power, nor 4000-m performance time nor VO <sub>2</sub> were significantly affected by either of the IP protocols compared to the sham at any time point following treatment. Repeated application of IP over seven days did not enhance the performance of trained cyclists in a 4000-m laboratory time trial. More research is required to understand how changes to methodological variables can improve the chances of IP successfully enhancing athlete performance.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 4","pages":"E91-E97"},"PeriodicalIF":0.0,"publicationDate":"2018-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1055/a-0639-5035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36816632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
João Paulo Brito, Nuno Garrido, Félix Romero, Adenilson Targino de Araújo Junior, Victor Machado Reis
{"title":"Effects of Backpack Load and Trekking Poles on Energy Expenditure During Field Track Walking.","authors":"João Paulo Brito, Nuno Garrido, Félix Romero, Adenilson Targino de Araújo Junior, Victor Machado Reis","doi":"10.1055/a-0637-8719","DOIUrl":"10.1055/a-0637-8719","url":null,"abstract":"<p><p>This study evaluates the effects of the use of backpack load and trekking poles on field track walking energy expenditure. Twenty male volunteer pole walkers (age: 22.70±2.89 years; body mass: 77.90±11.19 kg; height: 1.77±0.06 m; percentage of body fat: 14.6±6.0%) walked at a self-selected pace on a pedestrian field track over a period of more than six months. Each subject was examined at random based on four walking conditions: non-poles and non-load, with poles and non-load, non-poles and with load, with poles and with load. Heart rate, oxygen uptake and energy expenditure were continuously recorded by a portable telemetric system. Non-load walking speed was lower during walking with poles when compared with no poles ( <i>p</i> ≤0.05). Oxygen uptake, energy expenditure and heart rate varied significantly across different conditions. Our results suggest that the use of trekking poles does not influence energy expenditure when walking without an additional load, but it can have an effect during backpack load walking. Moreover, our results indicate that the use of trekking poles may not be helpful to lower the exertion perceived by the subjects when walking with an additional load.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 4","pages":"E117-E122"},"PeriodicalIF":0.0,"publicationDate":"2018-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/c1/67/10-1055-a-0637-8719.PMC6259461.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36773106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jesse A Goodrich, Benjamin J Ryan, William C Byrnes
{"title":"The Influence of Oxygen Saturation on the Relationship Between Hemoglobin Mass and VO <sub>2</sub> max.","authors":"Jesse A Goodrich, Benjamin J Ryan, William C Byrnes","doi":"10.1055/a-0655-7207","DOIUrl":"https://doi.org/10.1055/a-0655-7207","url":null,"abstract":"<p><p>Hemoglobin mass (tHb) is a key determinant of maximal oxygen uptake (VO <sub>2</sub> max). We examined whether oxyhemoglobin desaturation (ΔS <sub>a</sub> O <sub>2</sub> ) at VO <sub>2</sub> max modifies the relationship between tHb and VO <sub>2</sub> max at moderate altitude (1,625 m). Seventeen female and 16 male competitive, endurance-trained moderate-altitude residents performed two tHb assessments and two graded exercise tests on a cycle ergometer to determine VO <sub>2</sub> max and ΔS <sub>a</sub> O <sub>2</sub> . In males and females respectively, VO <sub>2</sub> max (ml·kg <sup>-1</sup> ·min <sup>-1</sup> ) ranged from 62.5-83.0 and 44.5-67.3; tHb (g·kg <sup>-1</sup> ) ranged from 12.1-17.5 and 9.1-13.0; and S <sub>a</sub> O <sub>2</sub> at VO <sub>2</sub> max (%) ranged from 81.7-94.0 and 85.7-95.0. tHb was related to VO <sub>2</sub> max when expressed in absolute terms and after correcting for body mass (r=0.94 and 0.86, respectively); correcting by ΔS <sub>a</sub> O <sub>2</sub> did not improve these relationships (r=0.93 and 0.83). Additionally, there was a negative relationship between tHb and S <sub>a</sub> O <sub>2</sub> at VO <sub>2</sub> max (r=-0.57). In conclusion, across a range of endurance athletes at moderate altitude, the relationship between tHb and VO <sub>2</sub> max was found to be similar to that observed at sea level. However, correcting tHb by ΔS <sub>a</sub> O <sub>2</sub> did not explain additional variability in VO <sub>2</sub> max despite significant variability in ΔS <sub>a</sub> O <sub>2</sub> ; this raises the possibility that tHb and exercise-induced ΔS <sub>a</sub> O <sub>2</sub> are not independent in endurance athletes.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 4","pages":"E98-E104"},"PeriodicalIF":0.0,"publicationDate":"2018-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1055/a-0655-7207","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36816633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tuck Jump Assessment as an Indicator for Upper Extremity Injury.","authors":"Jeff W Barfield, Gretchen D Oliver","doi":"10.1055/a-0655-7345","DOIUrl":"https://doi.org/10.1055/a-0655-7345","url":null,"abstract":"<p><p>The purpose of this study was to determine if tuck jumps can be used as a dynamic movement assessment to ascertain a previous history of upper extremity injury in an overhead throwing sport. Seventy-one youth baseball and softball athletes (28 baseball/43 softball; 12.41±2.22 yrs.; 161.98±13.65 cm; 59.17 ± 14.90 kg) were recruited to participate and were placed in either the previous injury (N=18) or no previous injury (N=53) groups. Kinematic data were collected from jumps 4 through 8 during a trial of 10 tuck jumps performed at 100 Hz using an electromagnetic tracking system (trakSTAR <sup>TM</sup> , Ascension Technologies, Inc., Burlington, VT, USA) synced with the MotionMonitor <sup>®</sup> (Innovative Sports Training, Chicago, IL, USA). A logistic regression showed no significance in trunk flexion or upper leg elevation in the ability to determine upper extremity injury ( <i>χ</i> <sup><i>2</i></sup> (1, <i>N</i> =71)=3.55, <i>p</i> =0.315). In conclusion, examining only trunk flexion and upper leg elevation during the tuck jump assessment (TJA) is not enough for clinicians to recognize previous upper extremity injury. Even though the body behaves as a kinetic chain, simplifying the dynamic movement assessment while not specifying the type of upper extremity injury is not favorable for the clinician to identify previous injury.</p>","PeriodicalId":74857,"journal":{"name":"Sports medicine international open","volume":"2 4","pages":"E113-E116"},"PeriodicalIF":0.0,"publicationDate":"2018-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1055/a-0655-7345","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36816635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}