Runners are sometimes advised to alter their strike pattern as a means of increasing performance or in response to injury. The purpose of this study was to compare lower extremity mechanics of rearfoot strikers (RFS), who were instructed to run with a forefoot strike pattern (CFFS) to those of a preferred forefoot striker (FFS). Three-dimensional mechanics of 9 FFS and 9 CFFS were evaluated. Peak values for most kinematic and kinetic variables and all patterns of movement were not found to be statistically different between CFFS and FFS. Only peak vertical ground reaction force and peak ankle plantarflexion moment were found to be significantly lower (p ≤ .05) in the CFFS group. This suggests that RFS are able to assume a FFS pattern with very little practice that is very similar to that of a preferred FFS. The impact of changing one's strike pattern on injury risk and running performance needs further study.
Dorsey S. Williams III, Irene S. McClay and Kurt T. Manal
Mark B. Andersen and Jean M. Williams
A theoretical model of stress and athletic injury is presented. The purpose of this paper is to propose a framework for the prediction and prevention of stress-related injuries that includes cognitive, physiological, attentional, behavioral, intrapersonal, social, and stress history variables. Development of the model grew from a synthesis of the stress-illness, stress-accident, and stress-injury literatures. The model and its resulting hypotheses offer a framework for many avenues of research into the nature of injury and reduction of injury risk. Other advantages of the model are that it addresses possible mechanisms behind the stress-injury relationship and suggests several specific interventions that may help diminish the likelihood of injury. The model also has the potential of being applied to the investigation of injury and accident occurrence in general.
Sarah K. Fields and R. Dawn Comstock
Rugby, a fast-paced, aggressive contact sport, has a high incidence of injury. This study examines why US women play rugby given the social stigma surrounding women’s participation in sports in general, particularly contact sports, and despite the high risk of injury. In a survey of their injury history and potential injury risk factors, 339 female rugby players from 14 teams of varied quality and levels of play from a wide geographic area in the United States were asked why they played the sport. Their responses indicate that women play rugby because they enjoy the game, they like the aggressive aspects of the sport, they appreciate the social aspects of the game, and they believe the sport provides them with positive benefits, such as increased fitness, confidence, and strength. The results of this study indicate that many women are willing to risk injury for the positive rewards that they associate with rugby.
Elizabeth C. J. Pike and Joseph A. Maguire
This paper provides a development from previous conceptual frameworks related to the risk/pain/injury nexus in sporting subcultures (Hughes & Coakley, 1991; Maguire & Roberts, 1998; Nixon, 1992; Young, 1991). To do this, we have developed a model of factors contributing to injury risk in sport. In outlining our framework we seek to trace the enabling and coercive social forces that combine to act upon athletes and consequently promote participation to the extent of risking injury. This paper is grounded in a two-year study of female rowers in the United Kingdom. Several dimensions of sporting activities are mapped out, including the physical and structural settings, or “stage” upon which the sport takes place; preparation and participation in the sport itself; and the athletes’ attitudes toward, and actions on, receiving an injury. The themes identified in the model are used to “make sense” of the substantive insights drawn from the rowers’ stories.
Irene S. McClay, John R. Robinson, Thomas P. Andriacchi, Edward C Frederick, Ted Gross, Philip Martin, Gordon Valiant, Keith R. Williams and Peter R. Cavanagh
Basketball is a sport that involves multiple impacts with the ground through a variety of moves such as running Jumping, and cutting. Repetitive impacts have been associated with stress-related injuries in other sports such as running. The purpose of this investigation was to gain an understanding of the typical stresses the body experiences during common basketball moves. To this end, the ground reaction forces from 24 players from five professional basketball teams were studied. In addition, a game analysis was performed to determine the frequency of selected moves. These data indicated that certain common movements, such as jump landings and shuffling, resulted in absolute and relative forces much greater than many of those reported previously in studies of other sports. These movements were also identified in a companion paper as being associated with large angular excursions and velocities. Findings are discussed with respect to injury risks, and suggestions for future study are made.
Urban Johnson, Johan Ekengren and Mark B. Andersen
This study examined the effectiveness of a prevention intervention program to lower the incidence of injury for soccer players with at-risk psychosocial profiles. The Sport Anxiety Scale, the Life Event Scale for Collegiate Athletes, and the Athletic Coping Skills Inventory-28 were used to screen for psychosocial risk factors outlined in the stress and injury model (Williams & Andersen, 1998). Thirty-two high injury-risk players were identified and randomly assigned to treatment and control groups. Injuries of participants were reported by their coaches. The intervention program consisted of training in 6 mental skills distributed in 6 to 8 sessions during 19 weeks of the competitive season. The results showed that the brief intervention prevention program significantly lowered the number of injuries in the treatment group compared with the control group.
Matthew C. Hoch, Lauren A. Welsch, Emily M. Hartley, Cameron J. Powden and Johanna M. Hoch
Context: The Y-Balance Test (YBT) is a dynamic balance assessment used as a preseason musculoskeletal screen to determine injury risk. While the YBT has demonstrated excellent test-retest reliability, it is unknown if YBT performance changes following participation in a competitive athletic season. Objective: Determine if a competitive athletic season affects YBT performance in field hockey players. Design: Pretest-posttest. Setting: Laboratory. Participants: 20 NCAA Division I women's field hockey players (age = 19.55 ± 1.30 y; height = 165.10 ± 5.277 cm; mass = 62.62 ± 4.64 kg) from a single team volunteered. Participants had to be free from injury throughout the entire study and participate in all athletic activities. Interventions: Participants completed data collection sessions prior to (preseason) and following the athletic season (postseason). Between data collections, participants competed in the fall competitive field hockey season, which was ~3 months in duration. During data collection, participants completed the YBT bilaterally. Main Outcome Measures: The independent variable was time (preseason, postseason) and the dependent variables were normalized reach distances (anterior, posteromedial, posterolateral, composite) and between-limb symmetry for each reach direction. Differences between preseason and postseason were examined using paired t tests (P ≤ .05) as well as Bland-Altman limits of agreement. Results: 4 players sustained a lower extremity injury during the season and were excluded from analysis. There were no significant differences between preseason and postseason reach distances for any reach directions on either limb (P ≥ .31) or in the between-limb symmetries (P ≥ .52). The limits of agreement analyses determined there was a low mean bias across measurements (≤1.67%); however, the 95% confidence intervals indicated there was high variability within the posterior reach directions over time (±4.75 to ± 14.83%). Conclusion: No changes in YBT performance were identified following a competitive field hockey season in Division I female athletes. However, the variability within the posterior reach directions over time may contribute to the limited use of these directions for injury risk stratification.
Abbey C. Thomas, Scott G. McLean and Riann M. Palmieri-Smith
Neuromuscular fatigue exacerbates abnormal landing strategies, which may increase noncontact anterior cruciate ligament (ACL) injury risk. The synergistic actions of quadriceps and hamstrings (QH) muscles are central to an upright landing posture, though the precise effect of simultaneous fatigue of these muscles on landing and ACL injury risk is unclear. Elucidating neuromechanical responses to QH fatigue thus appears important in developing more targeted fatigue-resistance intervention strategies. The current study thus aimed to examine the effects of QH fatigue on lower extremity neuromechanics during dynamic activity. Twenty-five healthy male and female volunteers performed three single-leg forward hops onto a force platform before and after QH fatigue. Fatigue was induced through sets of alternating QH concentric contractions, on an isokinetic dynamometer, until the first five repetitions of a set were performed at least 50% below QH peak torque. Three-dimensional hip and knee kinematics and normalized (body mass × height) kinetic variables were quantified for pre- and postfatigue landings and subsequently analyzed by way of repeated- measures mixed-model ANOVAs. QH fatigue produced significant increases in initial contact (IC) hip internal rotation and knee extension and external rotation angles (p < .05), with the increases in knee extension and external rotation being maintained at the time of peak vertical ground reaction force (vGRF) (p < .05). Larger knee extension and smaller knee fexion and external rotation moments were also evident at peak vGRF following fatigue (p < .05). Females landed with greater hip fexion and less abduction than males at both IC and peak vGRF as well as greater knee fexion at peak vGRF (p < .05). The peak vGRF was larger for females than males (p < .05). No sex × fatigue effects were found (p > .05). Fatigue of the QH muscles altered hip and knee neuromechanics, which may increase the risk of ACL injury. Prevention programs should incorporate methods aimed at countering QH fatigue.
Samantha E. Scarneo, Hayley J. Root, Jessica C. Martinez, Craig Denegar, Douglas J. Casa, Stephanie M. Mazerolle, Catie L. Dann, Giselle A. Aerni and Lindsay J. DiStefano
Neuromuscular training programs (NTPs) improve landing technique and decrease vertical ground-reaction forces (VGRFs), resulting in injury-risk reduction. NTPs in an aquatic environment may elicit the same improvements as land-based programs with reduced joint stress.
To examine the effects of an aquatic NTP on landing technique as measured by the Landing Error Scoring System (LESS) and VGRFs, immediately and 4 mo after the intervention.
Design and Setting:
Repeated measures, pool and laboratory.
Fifteen healthy, recreationally active women (age 21 ± 2 y, mass 62.02 ± 8.18 kg, height 164.74 ± 5.97 cm) who demonstrated poor landing technique (LESS-Real Time > 4).
All participants completed an aquatic NTP 3 times/wk for 6 wk.
Main Outcome Measures:
Participants’ landing technique was evaluated using a jump-landing task immediately before (PRE), immediately after (POST), and 4 mo after (RET) the intervention period. A single rater, blinded to time point, graded all videos using the LESS, which is a valid and reliable movement-screening tool. Peak VGRFs were measured during the stance phase of the jump-landing test. Repeated-measure analyses of variance with planned comparisons were performed to explore differences between time points.
LESS scores were lower at POST (4.46 ± 1.69 errors) and at RET (4.2 ± 1.72 errors) than at PRE (6.30 ± 1.78 errors) (P < .01). No significant differences were observed between POST and RET (P > .05). Participants also landed with significantly lower peak VGRFs (P < .01) from PRE (2.69 ± .72 N) to POST (2.23 ± .66 N).
The findings introduce evidence that an aquatic NTP improves landing technique and suggest that improvements are retained over time. These results show promise of using an aquatic NTP when there is a desire to reduce joint loading, such as early stages of rehabilitation, to improve biomechanics and reduce injury risk.
Giuliamarta Bottoni, Dieter Heinrich, Philipp Kofler, Michael Hasler and Werner Nachbauer
During sport activity, knee proprioception might worsen. This decrease in proprioceptive acuity negatively influences motor control and therefore may increase injury risk. Hiking is a common activity characterized by a higher-intensity-exercise phase during uphill walking and a lower-intensity-exercise phase during downhill walking. Pain and injuries are reported in hiking, especially during the downhill phase.
To examine the effect of a hiking-fatigue protocol on joint-position sense.
University research laboratory.
24 nonprofessional sportswomen without knee injuries.
Main Outcome Measures:
Joint-position sense was tested at the beginning, after 30 min uphill walking, and after 30 min downhill walking on a treadmill (continuous protocol).
After downhill walking, joint-position sense was significantly worse than in the test at the beginning (P = .035, α = .05). After uphill walking, no differences were observed in comparison with the test at the beginning (P = .172, α = .05) or the test after downhill walking (P = .165, α = .05).
Downhill walking causes impairment in knee-joint-position sense. Considering these results, injury-prevention protocols for hiking should focus on maintaining and improving knee proprioception during the descending phase.