Browse

You are looking at 111 - 120 of 24,894 items

Restricted access

Olfa Turki, Wissem Dhahbi, Johnny Padulo, Riadh Khalifa, Sana Ridène, Khaled Alamri, Mirjana Milić, Sabri Gueid and Karim Chamari

Purpose: To explore the immediate (15-s post-warm-up) and the delayed (after 20 and 40 min of simulated volleyball play) effects of 2 different warm-up protocols—a stretching-free volleyball warm-up (NS) and a warm-up incorporating dynamic stretching (DS)—on subsequent change of direction (COD) performance in young elite volleyball players. Methods: Sixteen male players (age 16.88 [0.34] y, body mass 75.81 [5.41] kg, body height 1.91 [0.05] m, body mass index 20.84 [1.79] kg·m−2, and body fat percentage 9.48 [1.83]%) from the U-17 national volleyball team performed NS and DS on 2 different nonconsecutive days. During each testing session (NS and DS), half T-test performance measurements were performed after 5 minutes of a general warm-up (ie, baseline), immediately post-warm-up (after 15 s), and after 20 and 40 minutes of simulated volleyball play. Results: For DS, a significant improvement in COD performance (2.08%, P < .001) was observed after 20 minutes of play compared with the baseline values. In addition, COD performance recorded after 40 minutes of play was better than after 15-second post-warm-up (5.85%, P = .001). Inferential statistics showed better COD performance in the DS condition after 20 minutes of play (2.32%, likely negative, d = 0.61). Conclusions: Compared with NS, DS tended to affect the pattern of improvement of COD performance during play by intensifying and accelerating it. Consequently, to enhance COD performance for up to 40 minutes into the game, it is recommended that DS be incorporated to the warm-up preceding the match.

Restricted access

Nicki Winfield Almquist, Gertjan Ettema, James Hopker, Øyvind Sandbakk and Bent R. Rønnestad

Background: Cycling competitions are often of long duration and include repeated high-intensity efforts. Purpose: To investigate the effect of repeated maximal sprints during 4 hours of low-intensity cycling on gross efficiency (GE), electromyography patterns, and pedaling technique compared with work-matched low-intensity cycling in elite cyclists. Methods: Twelve elite, male cyclists performed 4 hours of cycling at 50% of maximal oxygen uptake either with 3 sets of 3 × 30-second maximal sprints (E&S) during the first 3 hours or a work-matched cycling without sprints (E) in a randomized order. Oxygen uptake, electromyography, and pedaling technique were recorded throughout the exercises. Results: GE was reduced from start to the end of exercise in both conditions (E&S: 19.0 [0.2] vs 18.1 [0.2], E: 19.1% [0.2%] vs 18.1% [0.2%], both P = .001), with no difference in change between conditions (condition × time interaction, P = .8). Integrated electromyography increased from start to end of exercise in m. vastus lateralis and m. vastus medialis (m. vastus medialis: 9.9 [2.4], m. vastus lateralis: 8.5 [4.0] mV, main effect of time: P < .001 and P = .03, respectively) and E&S increased less than E in m. vastus medialis (mean difference −3.3 [1.5] mV, main effect of condition: P = .03, interaction, P = .06). The mechanical effectiveness only decreased in E&S (E&S: −2.2 [0.7], effect size = 0.24 vs E: −1.3 [0.8] percentage points: P = .04 and P = .8, respectively). The mean power output during each set of 3 × 30-second sprints in E&S did not differ (P = .6). Conclusions: GE decreases as a function of time during 4 hours of low-intensity cycling. However, the inclusion of maximal repeated sprinting does not affect the GE changes, and the ability to sprint is maintained throughout the entire session.

Restricted access

Corrado Lupo, Alexandru Nicolae Ungureanu, Riccardo Frati, Matteo Panichi, Simone Grillo and Paolo Riccardo Brustio

Purpose: To monitor elite youth female basketball training to verify whether players’ and coaches’ (3 technical coaches and 1 physical trainer) session rating of perceived exertion (s-RPE) has a relationship with Edwards’ method. Methods: Heart rate of 15 elite youth female basketball players (age 16.7 [0.5] y, height 178 [9] cm, body mass 72 [9] kg, body mass index 22.9 [2.2] kg·m−2) was monitored during 19 team (268 individual) training sessions (102 [15] min). Mixed effect models were applied to evaluate whether s-RPE values were significantly (P ≤ .05) related to Edwards’ data, total session duration, maximal intensity (session duration at 90–100% HRmax), type of training (ie, strength, conditioning, and technique), and whether differences emerged between players’ and coaches’ s-RPE values. Results: The results showed that there is a relationship between s-RPE and Edwards’ methods for the players’ RPE scores (P = .019) but not for those of the trainers. In addition, as expected, both players’ (P = .014) and coaches’ (P = .002) s-RPE scores were influenced by total session duration but not by maximal intensity and type of training. In addition, players’ and coaches’ s-RPE values differed (P < .001)—post hoc differences emerged for conditioning (P = .01) and technique (P < .001) sessions. Conclusions: Elite youth female basketball players are better able to quantify the internal training load of their sessions than their coaches, strengthening the validity of s-RPE as a tool to monitor training in team sports.

Restricted access

Teun van Erp, Dajo Sanders and Jos J. de Koning

Purpose: To describe the training intensity and load characteristics of professional cyclists using a 4-year retrospective analysis. Particularly, this study aimed to describe the differences in training characteristics between men and women professional cyclists. Method: For 4 consecutive years, training data were collected from 20 male and 10 female professional cyclists. From those training sessions, heart rate, rating of perceived exertion, and power output (PO) were analyzed. Training intensity distribution as time spent in different heart rate and PO zones was quantified. Training load was calculated using different metrics such as Training Stress Score, training impulse, and session rating of perceived exertion. Standardized effect size is reported as Cohen’s d. Results: Small to large higher values were observed for distance, duration, kilojoules spent, and (relative) mean PO in men’s training (d = 0.44–1.98). Furthermore, men spent more time in low-intensity zones (ie, zones 1 and 2) compared with women. Trivial differences in training load (ie, Training Stress Score and training impulse) were observed between men’s and women’s training (d = 0.07–0.12). However, load values expressed per kilometer were moderately (d = 0.67–0.76) higher in women compared with men’s training. Conclusions: Substantial differences in training characteristics exist between male and female professional cyclists. Particularly, it seems that female professional cyclists compensate their lower training volume, with a higher training intensity, in comparison with male professional cyclists.

Restricted access

Jonathon R. Staples, Kevin A. Schafer, Matthew V. Smith, John Motley, Mark Halstead, Andrew Blackman, Amanda Haas, Karen Steger-May, Matthew J. Matava, Rick W. Wright and Robert H. Brophy

Context: Patients with anterior cruciate ligament (ACL) tears are likely to have deficient dynamic postural stability compared with healthy sex- and age-matched controls. Objectives: To test the hypothesis that patients undergoing ACL reconstruction have decreased dynamic postural stability compared with matched healthy controls. Design: Prospective case-control study. Setting: Orthopedic sports medicine and physical therapy clinics. Patients or Other Participants: Patients aged 20 years and younger with an ACL tear scheduled for reconstruction were enrolled prospectively. Controls were recruited from local high schools and colleges via flyers. Interventions: Patients underwent double-stance dynamic postural stability testing prior to surgery, recording time to failure and dynamic motion analysis (DMA) scores. Patients were then matched with healthy controls. Main Outcome Measures: Demographics, time to failure, and DMA scores were compared between groups. Results: A total of 19 females and 12 males with ACL tears were matched with controls. Individuals with ACL tears were more active (Marx activity score: 15.7 [1.0] vs 10.8 [4.9], P < .001); had shorter times until test failure (84.4 [15.8] vs 99.5 [14.5] s, P < .001); and had higher (worse) DMA scores (627 [147] vs 481 [132], P < .001), indicating less dynamic postural stability. Six patients with ACL deficiency (1 male and 5 females) demonstrated lower (better) DMA scores than their controls, and another 7 (4 males and 3 females) were within 20% of controls. Conclusions: Patients undergoing ACL reconstruction had worse global dynamic postural stability compared with well-matched controls. This may represent the effect of the ACL injury or preexisting deficits that contributed to the injury itself. These differences should be studied further to evaluate their relevance to ACL injury risk, rehabilitation, and return to play.

Restricted access

Erin Calaine Inglis, Danilo Iannetta, Louis Passfield and Juan M. Murias

Purpose: To (1) compare the power output (PO) for both the 20-minute functional threshold power (FTP20) field test and the calculated 95% (FTP95%) with PO at maximal lactate steady state (MLSS) and (2) evaluate the sensitivity of FTP95% and MLSS to training-induced changes. Methods: Eighteen participants (12 males: 37 [6] y and 6 females: 28 [6] y) performed a ramp-incremental cycling test to exhaustion, 2 to 3 constant-load MLSS trials, and an FTP20 test. A total of 10 participants returned to repeat the test series after 7 months of training. Results: The PO at FTP20 and FTP95% was greater than that at MLSS (P = .00), with the PO at MLSS representing 88.5% (4.8%) and 93.1% (5.1%) of FTP and FTP95%, respectively. MLSS was greater at POST compared with PRE training (12 [8] W) (P = .002). No increase was observed in mean PO at FTP20 and FTP95% (P = .75). Conclusions: The results indicate that the PO at FTP95% is different to MLSS, and that changes in the PO at MLSS after training were not reflected by FTP95%. Even when using an adjusted percentage (ie, 88% rather than 95% of FTP20), the large variability in the data is such that it would not be advisable to use this as a representation of MLSS.

Restricted access

Rachel Vaccaro and Ted M. Butryn

Individuals suffering from mental illness face challenges that are related to stigma and lack of education that are often reinforced by the media. Specifically, the elite athletic culture is not conducive for athletes who suffer from mental illness because there is at times a belief that mental illnesses are less prevalent in elite sport. Even though incidence of mental illness in elite athletes has gained more prominence in the popular media, there is still a lack of research in this area. Specifically, there is limited research regarding media representations of athletes who suffer from mental illness. To address this gap in the literature, an ethnographic content analysis (ECA) was done to examine Suzy Favor Hamilton’s open discussion of bipolar disorder surrounding the release of her new memoir, Fast Girl: A Life Spent Running From Madness. ECA yielded one overarching theme with three supporting sub-themes. Results indicated that even though Favor Hamilton’s book worked to spread awareness, the media attention surrounding the book release represented omission of mental illness in the environment of athletics. Overall, sports culture provides an environment that is not often willing to accept that mental illnesses exist in athletes.

Restricted access

Niranjan Chakrabhavi and Varadhan SKM

A task involving an instructed finger movement causes involuntary movements in the noninstructed fingers of the hand, also known as finger interdependence. It is associated with both mechanical and neural mechanisms. The current experiment investigated the effect of finger interdependence due to systematic changes of the wrist posture, close to neutral. Eight right-handed healthy human participants performed submaximal cyclic flexion and extension at the metacarpophalangeal joint at 0° neutral, 30° extension, and 30° flexion wrist postures, respectively. The experiment comprised of an instruction to move one of the 4 fingers—index, middle, ring, and little. Movements of the instructed and noninstructed fingers were recorded. Finger interdependence was quantified using enslavement matrix, individuation index, and stationarity index, and it was compared across wrist postures. The authors found that the finger interdependence does not change with changes in wrist posture. Further analysis showed that individuation and stationarity indices were mostly equivalent across wrist postures, and their effects were much smaller than the average differences present among the fingers. The authors conclude that at wrist postures close to neutral, the finger interdependence is not affected by wrist posture.

Restricted access

Karen S. Meaney and Sonya L. Armstrong

Bullying in any context adversely affects individuals and organizations. Although bullying is typically conceived of as an issue specific to children in schoolyards, adult bullying is widespread, and the literature on workplace bullying continues to emerge as a scholarly focus. More specifically, academic bullying in higher-education institutions has been identified as an area of particular interest. Considerable literature exists that addresses definitions, characteristics, and effects of faculty bullying; however, the literature is scant regarding effective practice and policy that explicitly aim to prevent academic bullying. Furthermore, although this is a topic often discussed informally on university campuses, it does not appear to be addressed explicitly in formalized institutional policies. In this manuscript, the authors provide the findings of the initial stages of a content analysis aimed at exploring extant policy at public doctoral-granting universities. Implications and recommendations for policy development based on the results of this policy review are provided.

Restricted access

Yvonne G. Ellis, Dylan P. Cliff, Steven J. Howard and Anthony D. Okely

Purpose: To examine the acute effects of a reduced sitting day on executive function (EF) and musculoskeletal health in preschoolers. Methods: A sample of 29 children (54% boys; 4–5 y) participated in a randomized cross-over trial. Each child completed 2 protocols, which simulate a day at childcare in random order for 2.5 hours; a typical preschool day (50% sitting) and a reduced preschool day (25% sitting) where most sitting activities were replaced with standing activities. Sitting, standing, and stepping time were objectively assessed using an activPAL accelerometer. EF was evaluated using tablet-based EF assessments (inhibition, working memory, and task shifting). Musculoskeletal health was assessed using a handheld dynamometer and goniometer. Results: Compared with the typical preschool day, the reduced sitting day showed no significant differences for EF scores. Effect sizes for inhibition (d = 0.04), working memory (d = 0.02), and shifting (d = 0.11) were all small. For musculoskeletal health, no significant differences were reported after the reduced preschool day. The effect sizes for the hip extension force, hamstring flexibility, gastrocnemius length, and balancing on 1 leg were all small (d = 0.21, d = 0.25, d = 0.28, and d = 0.28). Conclusions: This study suggests that reducing sitting time is unlikely to result in acute changes in EF and musculoskeletal health among preschoolers.