Fatigue-induced alterations in foot mechanics may lead to structural overload and injury. To investigate how a high-intensity running exercise to exhaustion modifies ankle plantar-flexor and dorsiflexor strength and fatigability, as well as plantar-pressure distribution in adolescent runners. Controlled laboratory study. Academy research laboratory. Eleven male adolescent distance runners (age = 16.9 ± 2.0 years, height = 170.6 ± 10.9 cm, mass = 54.6 ± 8.6 kg) were tested. All participants performed an exhausting run on a treadmill. An isokinetic plantar-flexor and dorsiflexor maximal-strength test and a fatigue test were performed before and after the exhausting run. Plantar-pressure distribution was assessed at the beginning and end of the exhausting run. We recorded plantar-flexor and dorsiflexor peak torques and calculated the fatigue index. Plantar-pressure measurements were recorded 1 minute after the start of the run and before exhaustion. Plantar variables (ie, mean area, contact time, mean pressure, relative load) were determined for 9 selected regions. Isokinetic peak torques were similar before and after the run in both muscle groups, whereas the fatigue index increased in plantar flexion (28.1%; P = .01) but not in dorsiflexion. For the whole foot, mean pressure decreased from 1 minute to the end (−3.4%; P = .003); however, mean area (9.5%; P = .005) and relative load (7.2%; P = .009) increased under the medial midfoot, and contact time increased under the central forefoot (8.3%; P = .01) and the lesser toes (8.9%; P = .008). Fatigue resistance in the plantar flexors declined after a high-intensity running bout performed by adolescent male distance runners. This phenomenon was associated with increased loading under the medial arch in the fatigued state but without any excessive pronation.Context:
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Footwear should be designed to avoid trauma and injury to the skin of the feet that can favor bacterial and fungal infections. Procedures and substances for sanitizing the interior of shoes are uncommon but are important aspects of primary prevention against foot infections and unpleasant odor. To evaluate the efficacy of a sanitizing technique for reducing bacterial and fungal contamination of footwear. Crossover study. Mens Sana basketball team. Twenty-seven male athletes and 4 coaches (62 shoes). The experimental protocol required a first sample (swab), 1/shoe, at time 0 from inside the shoes of all athletes before the sanitizing technique began and a second sample at time 1, after about 4 weeks, April 2012 to May 2012, of daily use of the sanitizing technique. The differences before and after use of the sanitizing technique for total bacterial count at 36°C and 22°C for Staphylococcus spp, yeasts, molds, Enterococcus spp, Pseudomonas spp, Escherichia coli, and total coliform bacteria were evaluated. Before use of the sanitizing technique, the total bacterial counts at 36°C and 22°C and for Staphylococcus spp were greater by a factor of 5.8 (95% confidence interval [CI] = 3.42, 9.84), 5.84 (95% CI = 3.45, 9.78), and 4.78 (95% CI = 2.84, 8.03), respectively. All the other comparisons showed a reduction in microbial loads, whereas E coli and coliforms were no longer detected. No statistically significant decrease in yeasts (P = .0841) or molds (P = .6913) was recorded probably because of low contamination. The sanitizing technique significantly reduced the bacterial presence in athletes' shoes.Context:
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Roller massagers are used as a recovery and rehabilitative tool to initiate muscle relaxation and improve range of motion (ROM) and muscular performance. However, research demonstrating such effects is lacking. To determine the effects of applying a roller massager for 20 and 60 seconds on knee-joint ROM and dynamic muscular performance. Randomized controlled clinical trial. University laboratory. Ten recreationally active men (age = 26.6 ± 5.2 years, height = 175.3 ± 4.3 cm, mass = 84.4 ± 8.8 kg). Participants performed 3 randomized experimental conditions separated by 24 to 48 hours. In condition 1 (5 repetitions of 20 seconds) and condition 2 (5 repetitions of 60 seconds), they applied a roller massager to the quadriceps muscles. Condition 3 served as a control condition in which participants sat quietly. Visual analog pain scale, electromyography (EMG) of the vastus lateralis (VL) and biceps femoris during roller massage and lunge, and knee-joint ROM. We found no differences in pain between the 20-second and 60-second roller-massager conditions. During 60 seconds of roller massage, pain was 13.5% (5.7 ± 0.70) and 20.6% (6.2 ± 0.70) greater at 40 seconds and 60 seconds, respectively, than at 20 seconds (P < .05). During roller massage, VL and biceps femoris root mean square (RMS) EMG was 8% and 7%, respectively, of RMS EMG recorded during maximal voluntary isometric contraction. Knee-joint ROM was 10% and 16% greater in the 20-second and 60-second roller-massager conditions, respectively, than the control condition (P < .05). Finally, average lunge VL RMS EMG decreased as roller-massage time increased (P < .05). Roller massage was painful and induced muscle activity, but it increased knee-joint ROM and neuromuscular efficiency during a lunge.Context:
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Twenty-five percent of athletic trainers administer pickle juice (PJ) to treat cramping. Anecdotally, some clinicians provide multiple boluses of PJ during exercise but warn that repeated ingestion of PJ may cause hyperkalemia. To our knowledge, no researchers have examined the effect of ingesting multiple boluses of PJ on the same day or the effect of ingestion during exercise. To determine the short-term effects of ingesting a single bolus or multiple boluses of PJ on plasma variables and to characterize changes in plasma variables when individuals ingest PJ and resume exercise. Crossover study. Laboratory. Nine euhydrated men (age = 23 ± 4 years, height = 180.9 ± 5.8 cm, mass = 80.7 ± 13.8 kg, urine specific gravity = 1.009 ± 0.005). On 3 days, participants rested for 30 minutes, and then a blood sample was collected. Participants ingested 0 or 1 bolus (1 mL·kg−1 body weight) of PJ, donned sweat suits, biked vigorously for 30 minutes (approximate temperature = 37°C, relative humidity = 18%), and had a blood sample collected. They either rested for 60 seconds (0- and 1-bolus conditions) or ingested a second 1 mL·kg−1 body weight bolus of PJ (2-bolus condition). They resumed exercise for another 35 minutes. A third blood sample was collected, and they exited the environmental chamber and rested for 60 minutes (approximate temperature = 21°C, relative humidity = 18%). Blood samples were collected at 30 and 60 minutes postexercise. Plasma sodium concentration, plasma potassium concentration, plasma osmolality, and changes in plasma volume. The number of PJ boluses ingested did not affect plasma sodium concentration, plasma potassium concentration, plasma osmolality, or changes in plasma volume over time. The plasma sodium concentration, plasma potassium concentration, and plasma osmolality did not exceed 144.6 mEq·L−1 (144.6 mmol·L−1), 4.98 mEq·L−1 (4.98 mmol·L−1), and 289.5 mOsm·kg−1H2O, respectively, in any condition at any time. Ingesting up to 2 boluses of PJ and resuming exercise caused negligible changes in blood variables. Ingesting up to 2 boluses of PJ did not increase plasma sodium concentration or cause hyperkalemia.Context:
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The exact neuromechanical nature and relative contribution of the abdominal drawing-in maneuver (ADIM) to postural instability warrants further investigation in uninjured and injured populations. To determine the effects of the ADIM on static core and unipedal postural stability in nonathletes with core instability. Controlled laboratory study. University research laboratory. A total of 19 nonathletes (4 women: age = 22.3 ± 1.3 years, height = 164.0 ± 1.7 cm, mass = 56.0 ± 4.6 kg; 15 men: age = 24.6 ± 2.8 years, height = 172.6 ± 4.7 cm, mass = 66.8 ± 7.6 kg) with core instability. Participants received ADIM training with visual feedback 20 minutes each day for 7 days each week over a 2-week period. Core instability was determined using a prone formal test and measured by a pressure biofeedback unit. Unipedal postural stability was determined by measuring the center-of-pressure sway and associated changes in the abdominal muscle-thickness ratios. Electromyographic activity was measured concurrently in the external oblique, erector spinae, gluteus medius, vastus medialis oblique, tibialis anterior, and medial gastrocnemius muscles. All participants initially were unable to complete the formal test. However, after the 2-week ADIM training period, all participants were able to reduce the pressure biofeedback unit by a range of 4 to 10 mm Hg from an initial 70 mm Hg and maintain it at 60 to 66 mm Hg with minimal activation of the external oblique (t18 = 3.691, P = .002) and erector spinae (t18 = 2.823, P = .01) muscles. Monitoring of the pressure biofeedback unit and other muscle activations confirmed that the correct muscle contraction defining the ADIM was accomplished. This core stabilization was well maintained in the unipedal-stance position, as evidenced by a decrease in the center-of-pressure sway measures (t18 range, 3.953–5.775, P < .001), an increased muscle-thickness ratio for the transverse abdominis (t18 = −2.327, P = .03), and a reduction in external oblique muscle activity (t18 = 3.172, P = .005). We provide the first evidence to highlight the positive effects of ADIM training on core and postural stability in nonathletes with core instability.Context:
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Authors of the most recent study of athletic training (AT) services have suggested that only 42% of secondary schools have access to athletic trainers. However, this study was limited by a small sample size and was conducted more than 10 years ago. To determine current AT services in public secondary schools. Cross-sectional study. Public secondary schools in the United States. A total of 8509 (57%) of 14 951 secondary schools from all 50 states and Washington, DC, responded to the survey. Data on AT services were collected for individual states, National Athletic Trainers' Association districts, and the nation. Of the 8509 schools that responded, 70% (n = 5930) had AT services, including full-time (n = 3145, 37%), part-time (n = 2619, 31%), and per diem (n = 199, 2%) AT services, and 27% (n = 2299) had AT services from a hospital or physical therapy clinic. A total of 4075 of 8509 schools (48%) provided coverage at all sports practices. Eighty-six percent (2 394 284/2 787 595) of athletes had access to AT services. Since the last national survey, access to AT services increased such that 70% of respondent public secondary schools provided athletic trainers at sports games or practices. Approximately one-third of all public secondary schools had full-time athletic trainers. This number must increase further to provide appropriate medical coverage at athletic practices and games for secondary school athletes.Context:
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Researchers have examined the physical activity (PA) habits of certified athletic trainers; however, none have looked specifically at athletic training students. To assess PA participation and constraints to participation among athletic training students. Cross-sectional study. Entry-level athletic training education programs (undergraduate and graduate) across the United States. Participants were 1125 entry-level athletic training students. Self-reported PA participation, including a calculated PA index based on a typical week. Leisure constraints and demographic data were also collected. Only 22.8% (252/1105) of athletic training students were meeting the American College of Sports Medicine recommendations for PA through moderate-intensity cardiorespiratory exercise. Although 52.3% (580/1105) were meeting the recommendations through vigorous-intensity cardiorespiratory exercise, 60.5% (681/1125) were meeting the recommendations based on the combined total of moderate or vigorous cardiorespiratory exercise. In addition, 57.2% (643/1125) of respondents met the recommendations for resistance exercise. Exercise habits of athletic training students appear to be better than the national average and similar to those of practicing athletic trainers. Students reported structural constraints such as lack of time due to work or studies as the most significant barrier to exercise participation. Athletic training students experienced similar constraints to PA participation as practicing athletic trainers, and these constraints appeared to influence their exercise participation during their entry-level education. Athletic training students may benefit from a greater emphasis on work-life balance during their entry-level education to promote better health and fitness habits.Context:
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Female athletic trainers (ATs) tend to depart the profession of athletic training after the age of 30. Factors influencing departure are theoretical. Professional demands, particularly at the collegiate level, have also been at the forefront of anecdotal discussion on departure factors. To understand the career and family intentions of female ATs employed in the collegiate setting. Qualitative study. National Collegiate Athletic Association Division I. Twenty-seven female ATs (single = 14, married with no children = 6, married with children = 7) employed in the National Collegiate Athletic Association Division I setting. All female ATs responded to a series of open-ended questions via reflective journaling. Data were analyzed via a general inductive approach. Trustworthiness was established by peer review, member interpretive review, and multiple-analyst triangulation. Our participants indicated a strong desire to focus on family or to start a family as part of their personal aspirations. Professionally, many female ATs were unsure of their longevity within the Division I collegiate setting or even the profession itself, with 2 main themes emerging as factors influencing decisions to depart: family planning persistence and family planning departure. Six female ATs planned to depart the profession entirely because of conflicts with motherhood and the role of the AT. Only 3 female ATs indicated a professional goal of persisting at the Division I setting regardless of their family or marital status, citing their ability to maintain work-life balance because of support networks. The remaining 17 female ATs planned to make a setting change to balance the roles of motherhood and AT because the Division I setting was not conducive to parenting. Our results substantiate those of previous researchers, which indicate the Division I setting can be problematic for female ATs and stimulate departure from the setting and even the profession.Context:
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The average retention rate for students enrolled in undergraduate athletic training programs (ATPs) nationwide has been reported to be 81%, and slightly more than half of program directors (PDs) have indicated that retention of athletic training students (ATSs) is a problem. However, why PDs do or do not believe ATS retention is problematic is unknown. To determine why PDs do or do not believe ATS retention is problematic. Qualitative study. Undergraduate ATPs. We obtained responses from 177 of the 343 PDs (51.6%). Using data saturation as a guide, we randomly selected 16 PDs from the survey responses to participate in follow-up telephone interviews; 8 believed retention was a problem and 8 did not. During audio-recorded telephone interviews, we asked PDs why they thought retention was or was not a problem for athletic training education. Following verbatim transcription, we used grounded theory to analyze the interview data and maintained trustworthiness by using intercoder agreement, member checks, and peer review. Program directors believed that retaining ATSs was a problem because students lack information regarding athletic training and the rigor of the ATP. Program directors were consistent in their perception that ATPs do not have a retention challenge because of the use of a secondary admissions process. This finding was likely based on personal use of a secondary admissions process in the ATPs these PDs lead. Program directors who lead ATPs that struggle to retain ATSs should consider using a secondary admissions process. During the preprofessional phase of the ATP, faculty and staff should work to socialize students to the demands of the ATP and the professional lives of athletic trainers.Context:
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Physical activity may affect the concentrations of circulating endogenous hormones in female athletes. Understanding the relationship between athletic and physical activity and circulating female hormone concentrations is critical. To test the hypotheses that (1) the estradiol-progesterone profile of high school adolescent girls participating in training, conditioning, and competition would differ from that of physically inactive, age-matched adolescent girls throughout a 3-month period; and (2) athletic training and conditioning would alter body composition (muscle, bone), leading to an increasingly greater lean–body-mass to fat–body-mass ratio with accompanying hormonal changes. Cohort study. Laboratory and participants' homes. A total of 106 adolescent girls, ages 14–18 years, who had experienced at least 3 menstrual cycles in their lifetime. Participants were prospectively monitored throughout a 13-week period, with weekly physical activity assessments and 15 urine samples for estrogen, luteinizing hormone, creatinine, and progesterone concentrations. Each girl underwent body-composition measurements before and after the study period. Seventy-four of the 98 girls (76%) who completed the study classified themselves as athletes. Body mass index, body mass, and fat measures remained stable, and 17 teenagers had no complete menstrual cycle during the observation period. Mean concentrations of log(estrogen/creatinine) were slightly greater in nonathletes who had cycles of <24 or >35 days. Mean log(progesterone/creatinine) concentrations in nonathletes were less in the first half and greater in the second half of the cycle, but the differences were not statistically significant. A moderate level of athletic or physical activity did not influence urine concentrations of estrogen, progesterone, or luteinizing hormones. However, none of the participants achieved high levels of physical activity. A significant number (17%) of girls in both activity groups were amenorrheic during the 3-month study period.Context:
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Increased Ligament Thickness in Previously Sprained Ankles as Measured by Musculoskeletal Ultrasound
Lateral ankle sprains are among the most common injuries in sport, with the anterior talofibular ligament (ATFL) most susceptible to damage. Although we understand that after a sprain, scar tissue forms within the ligament, little is known about the morphologic changes in a ligament after injury. To examine whether morphologic differences exist in the thickness of the ATFL in healthy, coper, and unstable-ankle groups. Cross-sectional study. Laboratory. A total of 80 National Collegiate Athletic Association Division I collegiate athletes (43 women, 37 men, age = 18.2 ± 1.1 years, height = 175.8 ± 11.1 cm, body mass = 75.0 ± 16.9 kg) participated in this study. They were categorized into the healthy, coper, or unstable group by history of ankle sprains and score on the Cumberland Ankle Instability Tool. A musculoskeletal sonographic image of the ATFL was obtained from each ankle. Thickness of the ATFL was measured at the midpoint of the ligament between the attachments on the lateral malleolus and talus. A group-by-limb interaction was evident (P = .038). The ATFLs of the injured limb for the coper group (2.20 ± 0.47 mm) and the injured limb for the unstable group (2.28 ± 0.53 mm) were thicker than the ATFL of the “injured” limb of the healthy group (1.95 ± 0.29 mm) at P = .015 and P = .015, respectively. No differences were seen in the uninjured limbs among groups. Because ATFL thicknesses of the healthy group's uninjured ankles were similar, we contend that lasting morphologic changes occurred in those with a previous injury to the ankle. Similar differences were seen between the injured limbs of the coper and unstable groups, so there must be another explanation for the sensations of instability and the reinjuries in the unstable group.Context:
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Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Cross-sectional study. Health Science Laboratory. A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.Context:
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Injuries are a major adverse event in a soccer player's career. Reducing injury incidence requires a thorough knowledge of the epidemiology of soccer injuries. To investigate the incidence and characteristics of injuries in the Dutch premier soccer league. Cohort study. The Dutch premier soccer league. During the 2009–2010 soccer season, a total of 217 professional soccer players from 8 teams were prospectively followed. The medical staff recorded time-loss injuries, including information on injuries (ie, type, body part, duration) and exposure data for training sessions and matches. A total of 286 injuries were recorded, affecting 62.7% of the players. The overall injury incidence was 6.2 injuries per 1000 player-hours, 2.8 in training sessions and 32.8 in matches. Most of the recorded injuries were acute (68.5%). Eight percent of the injuries were classified as recurrent. Injuries were most likely to be located in the lower extremities (82.9%). Injury time loss ranged from 1 to 752 days, with a median of 8 days. Knee injuries had the greatest consequences in terms of days of absence from soccer play (on average, 45 days). The most common diagnosis was muscle/tendon injury of the lower extremities (32.9%). Injury risk in the Dutch premier soccer league is high, especially during matches. Preventive measures should focus on the most common diagnoses, namely, muscle/tendon injuries of the lower extremities.Context:
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Successful training involves structured overload but must avoid the combination of excessive overload and inadequate recovery. The aim of this study was to determine the incidence of functional overreaching (FOR), nonfunctional overreaching (NFOR), and overtraining syndrome in elite female wrestlers during their normal training and competition schedules and to explore the utility of blood markers for the early detection of overreaching. Classification of FOR, NFOR, and overtraining syndrome was based on the European Congress of Sports Medicine position statement. Case series. China Institute of Sport Science. Over an 8-year period, 114 wrestlers from the women's Asian wrestling team were monitored to help identify if and when they experienced FOR, NFOR, or overtraining syndrome. Creatine kinase, hemoglobin, testosterone, and cortisol were measured throughout the period to identify whether wrestlers were outside the reference intervals (constructed from normal recovery data) during periods of overreaching and not overreaching. Among the 114 athletes, there were 13 (3.6%) instances of FOR, 23 (6.4%) instances of NFOR, and 2 (0.6%) instances of overtraining syndrome. The diagnostic sensitivity for FOR was 38%, 15%, 45%, and 18% for creatine kinase, hemoglobin, testosterone, and cortisol, respectively. The diagnostic sensitivity for NFOR was 29%, 33%, 26%, and 35% for creatine kinase, hemoglobin, testosterone, and cortisol, respectively. Specificity was 79%, 88%, 90%, and 82% for creatine kinase, hemoglobin, testosterone, and cortisol, respectively. Post hoc analysis showed no mean differences in creatine kinase (F = 0.5, P = .47), hemoglobin (F = 3.8, P = .052), testosterone (F = 0.2, P = .62), or cortisol (F = 0.04, P = .85) between monitoring periods when wrestlers were and were not diagnosed with FOR and NFOR. Coaches and sports scientists should not use single blood variables as markers of overreaching in elite female wrestlers.Context:
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Reliability and Validity of the Functional Assessment of Neurocognition in Sport (FANS): A Paradigm Shift in Post-Concussion Return-to-Sport Decision-Making
Driving After Concussion: Clinical Measures Associated with Post-concussion
The role of shoulder posture in pitching mechanics and injury risk in high school baseball pitchers
Corticospinal Excitability during Standing and Its Association with Postural Control Following Acute Lateral Ankle Sprain.
The socio-economic cost of anterior cruciate ligament injuries and lateral ankle sprains in amateur football and basketball.
JAT eISSN: 1938-162X
JAT ISSN: 1062-6050
ATEJ ISSN: 1947-380X