Kinetic risk factors of running-related injuries in female recreational runners.

Our objective was to prospectively investigate the association of kinetic variables with running-related injury (RRI) risk. Seventy-four healthy female recreational runners ran on an instrumented treadmill while 3D kinetic and kinematic data were collected. Kinetic outcomes were vertical impact transient, average vertical loading rate, instantaneous vertical loading rate, active peak, vertical impulse, and peak braking force (PBF). Participants followed a 15-week half-marathon training program. Exposure time (hours of running) was calculated from start of program until onset of injury, loss to follow-up, or end of program. After converting kinetic variables from continuous to ordinal variables based on tertiles, Cox proportional hazard models with competing risks were fit for each variable independently, before analysis in a forward stepwise multivariable model. Sixty-five participants were included in the final analysis, with a 33.8% injury rate. PBF was the only kinetic variable that was a significant predictor of RRI. Runners in the highest tertile (PBF < -0.27 BW) were injured at 5.08 times the rate of those in the middle tertile and 7.98 times the rate of those in the lowest tertile. When analyzed in the multivariable model, no kinetic variables made a significant contribution to predicting injury beyond what had already been accounted for by PBF alone. Findings from this study suggest PBF is associated with a significantly higher injury hazard ratio in female recreational runners and should be considered as a target for gait retraining interventions.

Functional knee brace use by non-injured subjects while performing an anaerobic capacity task: preliminary study.

AIM: The objective of this paper was to investigate if performance was hindered in non-injured braced athletes during an anaerobic task. If performance was affected, could accommodation to wearing a knee brace occur and thus decreasing performance hindrance concern while using a functional knee brace (FKB). METHODS: A 2x3 non-braced (NBr) and braced repeated measure factorial design. Five healthy athletes completed all testing. Subjects performed the Repeated High Intensity Shuttle Test (RHIST) over six days (three days NBr and three days braced). Running times were recorded each testing day to determine performance measures and percent fatigue levels while using a FKB and if accommodation to FKB use was possible. RESULTS: Non significant (F1,4=1.42, P=0.299) faster group mean performance time, was recorded for braced subjects relative to the non-braced condition. Although relatively faster performance levels were noted during the braced testing conditions during days 1 and 3 compared to the non-braced condition, these results were also not significant (F2,8=2.82, P=0.118). Lower percent fatigue level was recorded during all three braced days compared to non-braced days. Further, a tendency for accommodation to knee brace trend use was noted as the percentage performance difference between the two conditions had decreased by the last day of testing. CONCLUSION: Use of a knee brace did not hinder performance once accommodation to using the knee brace occurred and fatigue was not a factor while using a knee brace. Additional research, using a larger sample size and longer testing duration, is required to confirm the potential accommodation trend.

Sonographically guided intratendinous injections of hyperosmolar dextrose/lidocaine: a pilot study for the treatment of chronic plantar fasciitis.

OBJECTIVE: To report on the effectiveness of sonographically guided injections of hyperosmolar dextrose at reducing the pain associated with chronic plantar fasciitis. DESIGN: Case series. SETTING: Ultrasound division of St Paul's Hospital. PATIENTS: 20 referrals (3 men, 17 women; age 51 (SD 13) years) from local sports medicine primary care practitioners who had failed previous conservative treatments. INTERVENTIONS: A 27-gauge needle administered a 25% dextrose/lidocaine solution under sonographic guidance at 6 week intervals returning for a median of three consultations. MAIN OUTCOME MEASURES: Visual analogue scale (VAS) items for pain levels at rest (VAS1), activities of daily living (VAS2), and during or after physical activity (VAS3) were recorded at baseline and at the final treatment consultation (post-test). A telephone interview conducted an average of 11.8 months after the post-test consultation provided a measure of long-term follow-up. RESULTS: 16 patients reported a good to excellent outcome, while the symptoms in 4 patients were unchanged. There was a significant decrease (p<0.001) in all mean VAS items from pre-test to post-test: VAS1 (36.8 (SD 25.6) to 10.3 (10.9)), VAS2 (74.7 (20.8) to 25.0 (27.7)) and VAS3 (91.6 (9.2) to 38.7 (35.1)) and there were no apparent changes after the follow-up interview. CONCLUSIONS: Sonographically guided dextrose injections showed a good clinical response in patients with chronic plantar fasciitis insofar as pain was reduced during rest and activity. Further studies including a control group are needed to validate these outcomes.

Injury profile of elite under-21 age female field hockey players.

AIM: The objective of this paper was to identify the rate, profile, and severity of injuries associated with participating on a provincial/state hockey (field) and compare these data, where possible, with available ice hockey data. METHODS: An injury was defined as ''any event, during team or team-related game, practice, and/or activity (on or off the playing surface), requiring any attention by the team's Therapist and/or Physician and subsequent game and/or practice time-loss''. Seventy-five players, under the age of 21 years participated in the study over a 5-year duration. All injury data were collected post-injury. Data were collected on the player position, games versus practice conditions, injury time, injury type, injury etiology, anatomical region and plane injured, injury status, and duration required to return to full activity. RESULTS: A total of 2 828 athletes exposure's and 198 injuries were recorded. The combined injury rate was 70 injuries per 1 000 player game and practice exposures with significantly higher risk of injury resulting during the second half of a game or practice. Backs experienced the highest percentage and have a higher risk of injuries. The predominant injuries sustained included muscle strains, followed by tendonitis, while the highest number of injuries resulted from no contact. The lower back and ankle/foot were the most vulnerable to injury, followed by the knee. CONCLUSION: From this study it can be concluded that hockey (field) players can experience higher injury rates than ice hockey. Also, field hockey players are at greater risk of injury depending on the playing position and are more likely to be injured during the latter duration of a game and/or practice. In identifying injury trends related to hockey, injury prevention strategies should be developed as players use limited protective equipment.

Kleine-Levin syndrome: a unique cause of fatigue in an athlete.

Kleine-Levin syndrome (KLS) is a rare disorder characterised, most notably, by periodic episodes of hypersomnolence and hyperphagia. Associated features of the disorder include a lack of concentration, mood changes, and anxiety. Laboratory tests may show slight changes in the electroencephalogram. However, clinical presentation and laboratory tests are normal during asymptomatic intervals. KLS most often presents in adolescent males, with complete recovery by the 3rd to 4th decade of life. Possible precipitating factors include excessive workload, febrile illness, and respiratory infections. Presented is a classical case of KLS in an adolescent male athlete. The patient's history, complete laboratory results, and symptoms are discussed. Possible treatments for this disorder are also mentioned, along with diagnostic criteria.

Osteitis pubis in athletes. Infection, inflammation or injury?

Medical records of 59 patients (9 females and 50 males), who presented to sports medicine clinics at the Australian Institute of Sport and the University of British Columbia between 1985 and 1990 and who were diagnosed as suffering osteitis pubis, were reviewed and comparison of data obtained was made with the literature. Women average 35.5 years of age (30 to 59 years) and men 30.3 years (13 to 61 years). Sports most frequently involved were running, soccer, ice hockey and tennis. Clinical presentations of osteitis pubis fell into 4 main groups. 'Mechanical' (sport-related) was the largest group (n = 48), followed by 'obstetric' (n = 5), 'inflammatory' (n = 4) and 'other' (n = 2). Period of follow-up averaged 10.3 months (1 to 20 months) in women and 17.5 months (2 to 96 months) in men. Full recovery, when documented, averaged 9.5 months in men and 7.0 months in women. Osteitis pubis recurred in 25% of these men and none of these women at follow-up. The most frequent symptoms were pubic pain and adductor pain. Men also presented with lower abdominal, hip and perineal or scrotal pain; women with hip pain. Most common signs were tenderness of the pubic symphysis and tenderness of adductor longus muscle origin. Men also revealed tenderness of one or both the superior pubic rami and evidence of decreased hip rotation (unilateral or bilateral). Evidence of pelvic malalignment and/or sacroiliac dysfunction was frequently seen in both men and women. There was poor correlation between radiographic and isotope bone scan findings and the site and duration of symptoms and signs. Femoral head ratios were estimated on 30 hips in the series and 2 were judged to be at the upper limit of normal, perhaps indicating a form of epiphysiolysis producing tilt deformity of the head of the femur. It is clear that osteitis pubis in athletes is not uncommon and that factors such as loss of rotation of hips and previous obstetric history are important in the aetiology and management of this condition. Pelvic infection, which was believed to be the primary factor of osteitis pubis in the literature up until the 1970s, plays a very small role in this condition in athletes.

The role of biomechanics in the epidemiology of injuries.

In this paper a review of the epidemiology of both traumatic and overuse injuries is presented with special emphasis on the role of biomechanics. Biomechanical analysis of injuries and the specific sports has increased in sophistication to such a degree we have a much better understanding of both aetiology and management. Particularly in the area of overuse injuries this biomechanical data can also be utilised in prevention. This paper discusses acute traumatic injuries with emphasis on knee injuries. A detailed examination of knee injuries during skiing is explored. In addition, cervical injuries in gridiron football and rugby are outlined. Overuse injuries occurring during running are next discussed. Aetiological factors including training errors, muscular dysfunction and inflexibility, footwear, running gait and lower extremity malalignment are considered. Overuse injuries in swimming, dance, gymnastics and throwing sports are briefly discussed. Biochemical analysis is felt to be important in developing strategies that lead to rule changes, alteration of training techniques and improvement in equipment and footwear.

Running shoes, orthotics, and injuries.

Running is the most visible expression of the continued interest in regular physical activities. Unfortunately injuries are common, primarily due to overuse, and a number of aetiological factors have been recognised. Of these, training errors can be responsible for up to 60% of injuries. The training surface, a lack of flexibility and strength, the stage of growth and development, poor footwear and abnormal biomechanical features have all been implicated in the development of running injuries. A thorough understanding of the biomechanics of running is a necessary prerequisite for individuals who treat or advise runners. Clinically, the configuration of the longitudinal arch is a valuable method of classifying feet and has direct implications on the development and management of running problems. The runner with excessively pronated feet has features which predispose him/her to injuries that most frequently occur at the medial aspect of the lower extremity: tibial stress syndrome; patellofemoral pain syndrome; and posterior tibialis tendinitis. These problems occur because of excessive motion at the subtalar joint and control of this movement can be made through the selection of appropriate footwear, plus orthotic foot control. The runner with cavus feet often has a rigid foot and concomitant problems of decreased ability to absorb the force of ground contact. These athletes have unique injuries found most commonly on the lateral aspect of the lower extremity: iliotibial band friction syndrome; peroneus tendinitis; stress fractures; trochanteric bursitis; and plantar fasciitis. Appropriate footwear advice and the use of energy-absorbing materials to help dissipate shock will benefit these individuals. Running shoes for the pronated runner should control the excessive motion. The shoes should be board-lasted, straight-lasted, have a stable heel counter, extra medial support, and a wider flare than the shoes for the cavus foot. For these athletes a slip-lasted, curve-lasted shoe with softer ethylene vinyl acetate (EVA) and a narrow flare is appropriate. Orthotic devices are useful in selected runners with demonstrated biomechanical abnormalities that contribute to the injury. Soft orthotics made of a commercial insole laminated with EVA are comfortable, easily adjusted, inexpensive, and more for-giving than the semirigid orthotics which are useful in cases where the soft orthotic does not provide adequate foot control. A review of injury data shows an alarming rise in the incidence of knee pain in runners-from 18% to 50% of injuries in 13 years.(ABSTRACT TRUNCATED AT 400 WORDS)

Factors associated with exercise adherence among older adults. An individual perspective.

This paper reviews the literature concerning factors at the individual level associated with regular exercise among older adults. Twenty-seven cross-sectional and 14 prospective/longitudinal studies met the inclusion criteria of a mean participant age of 65 years or older. The findings are summarised by demographics, exercise experience, exercise knowledge, physiological factors, psychological factors, activity preferences and perceived social influences. In general, education and exercise history correlate positively with regular exercise, while perceived physical frailty and poor health may provide the greatest barrier to exercise adoption and adherence in the elderly. Social-cognitive theories identify several constructs that correlate with the regular exercise behaviour of older adults, such as exercise attitude, perceived behavioural control/self-efficacy, perceived social support and perceived benefits/barriers to continued activity. As well, stage modelling may provide additional information about the readiness for regular exercise behaviour among older adults. However, relatively few studies among older adults exist compared with middle-aged and younger adults. Further, the majority of current research consists of cross-sectional designs or short prospective exercise trials among motivated volunteers that may lack external validity. Future research utilising longitudinal and prospective designs with representative samples of older adults will provide a better understanding of significant causal associations between individual factors and regular exercise behaviour.

Scintigraphic uptake of 99mTc at non-painful sites in athletes with stress fractures. The concept of bone strain.

Stress fractures are commonly found in athletes attending sports medicine clinics for diagnosis of lower limb pain. Plain radiographs are less reliable than the 99mTc bone scan for diagnosing stress fractures because of their low sensitivity. While the heightened sensitivity of the bone scan is advantageous as a diagnostic aid, the uptake of 99mTc at non-painful sites occurs frequently in the athlete. Although the clinical significance has not been determined, asymptomatic uptake may indicate bone remodelling as part of a continuum of adaptation to physical stress. It is not known whether athletes who have uptake of 99mTc in asymptomatic areas represent a separate population from those who do not. This study retrospectively reviewed the medical charts and bone scan reports of 320 athletes diagnosed as having stress fractures, to determine the frequency of asymptomatic focal uptake at sites other than the site of pain. This group was compared with the group who had no asymptomatic uptake on a number of demographic variables and physical findings. Asymptomatic focal uptake was found in 37.5% of athletes with the average number of sites being 1.8 per person. No significant differences between groups with focal asymptomatic uptake and groups with no asymptomatic uptake were found when compared for age, height, weight, mileage in runners, times to diagnosis and recovery, frequency of tenderness, swelling, trauma history, varus alignment, and x-ray abnormalities. It is concluded that asymptomatic uptake of 99mTc occurs frequently in athletes with stress fractures and there are no significant clinical differences between the group with asymptomatic uptake and the group without. It is suggested that symptomatic uptake of 99mTc represents the remodelling response of bone to physical stress.

Achilles tendon disorders in runners--a review.

The Achilles tendon and the classification, etiology, diagnosis, treatment, and management of Achilles tendon disorders in runners are reviewed. Due to the presence of a paratenon sheath, the classification of Achilles tendon disease should be revised. Several etiological mechanisms have been proposed in Achilles tendon disease. The authors recognize: faulty foot biomechanics; poor lower leg flexibility; poorly designed athletic footwear; training surfaces; training intensity; overuse through excessive mileage; inactivity; local steroid injections; rheumatic conditions; and indirect violence. An accurate, thorough differential diagnosis is essential when the athlete presents with an Achilles tendon disorder. Except in total rupture and in extensive partial rupture, the authors do not recommend cast immobilization in the treatment of Achilles tendon disease. When the athlete presents with total rupture of the Achilles tendon, the authors believe that surgical repair is the treatment method of choice. Rehabilitation programs to follow successful treatment of Achilles tendon disease are also presented.

Effects of menstrual cycle phase on athletic performance.

The purpose of this study was to examine the effects of menstrual cycle phase on four selected indices of athletic performance: aerobic capacity, anaerobic capacity, isokinetic strength, and high intensity endurance. Sixteen eumenorrheic women (VO2max > or = 50 ml.kg-1.min-1) were tested during the early follicular (F) and midluteal (L) phases of the menstrual cycle. Cycle phases were confirmed by serum estradiol and progesterone assays. No significant differences were observed between F and L tests in weight, percent body fat, sum of skinfolds, hemoglobin concentration, hematocrit, maximum heart rate, maximum minute ventilation, maximum respiratory exchange ratio, anaerobic performance, endurance time to fatigue (at 90% of VO2max), or isokinetic strength of knee flexion and extension. Both absolute and relative VO2max, however, were slightly lower in L than in F (F = 3.19 +/- 0.09.min-1, L = 3.13 +/- 0.08.min-1, P = 0.04; and F = 53.7 +/- 0.9 ml.kg-1.min-1, L = 52.8 +/- 0.8 ml.kg-1.min-1, P = 0.06). These results suggest that the cyclic increases in endogenous female steroid hormones of an ovulatory menstrual cycle may have a slight, deleterious influence on aerobic capacity, with potential implications for individual athletes. Nevertheless, the cycle phase did not impact significantly on the majority of the other performance tests and cardiorespiratory variables measured in this study.

The effects of prelatent/latent iron deficiency on physical work capacity.

In order to examine the effects of mild iron deficiency on physical work capacity, 40 prelatent iron-deficient female endurance runners were studied before and after 8 wk of supplementation with either oral iron (320 mg ferrous sulfate) or a matching placebo. Subjects underwent the following physical work capacity tests: the Wingate cycle ergometer test, the anaerobic speed test, the ventilatory threshold, VO2max, and maximal treadmill velocity during the VO2max test. Muscle biopsy samples pre- and post-treatment were obtained from 17 of the subjects, and these were assayed for citrate synthase and cytoplasmic alpha-glycerophosphate dehydrogenase activity. Subjects were randomly assigned to one of the treatment groups, and a double-blind method of administration of the supplements was used. The differences in improvement scores between the two groups on the work capacity and enzyme activity variables were statistically nonsignificant (P greater than 0.05). Serum ferritin values rose from a mean of 12.4 +/- 4.5 to 37.7 +/- 19.7 ng.ml-1 for the experimental group and from 12.2 +/- 4.3 to 17.2 +/- 8.9 ng.ml-1 for the controls (P = 0.0025), whereas hemoglobin levels remained fairly constant for both groups (P = 0.6). Eight weeks of iron supplementation to prelatent/latent iron-deficient, physically active females did not significantly enhance work capacity. Within the limitations of this study, the presence of a serum ferritin below 20 ng.ml-1 does not pose a significant handicap to physical work capacity.

Musculoskeletal injuries associated with physical activity in older adults.

In order to compare the clinical presentation of overuse injuries in older and younger athletes, retrospective patient chart data were obtained from cases which had been referred to an outpatient sports medicine clinic over a 5-yr period. A total of 1,407 cases were studied comprising two populations separated by significantly (P less than 0.001) different ages: 685 "old" (mean age = 56.9 +/- 6.1 yr) and 722 "young" (mean age = 30.4 +/- 8.1 yr). Although the two subpopulations demonstrated modest differences in sport activity at the time of injury, specific diagnoses, and anatomic location of injury, many similarities existed between the groups. Running, fitness classes, and field sports were more commonly associated with injury in the younger group, while racquet sports, walking, and low intensity sports were more commonly associated with injury in the older group. The frequency of tendinitis was similar in both age groups, while metatarsalgia, plantar fasciitis, and meniscal injury were more common in the older population, and patellofemoral pain syndrome (PFPS) and stress fracture/periostitis were more common in the younger population. Anatomically, injury sites in the foot were more frequent in the older group, while injury sites in the knee were more frequent in the younger group. In the older population, the prevalence of osteoarthritis was 2.5 times higher than the frequency of osteoarthritis as the source of activity-related pain. In the older group, 85% of the diagnoses were overuse injuries known to respond to conservative treatment, 14.4% of the cases required consultative referral, and only 4.1% required surgery.

Achilles tendinitis and peritendinitis: etiology and treatment.

One hundred nine runners were treated conservatively without immobilization for overuse injury to the Achilles tendon. Treatment strategies were directed toward rehabilitation of the gastrocnemius/soleus muscle-tendon unit, control of inflammation and pain, and control of biomechanical parameters. One fair, 12 good, and 73 excellent results were reported, with a mean recovery time of 5 weeks. Followup was incomplete in 23 cases. The three most prevalent etiological factors were overtraining (82 cases), functional overpronation (61 cases), and gastrocnemius/soleus insufficiency (41 cases). The authors speculate that runners are susceptible to Achilles tendinitis with peritendinitis due to microtrauma produced by the eccentric loading of fatigued muscle, excess pronation producing whipping action of the Achilles tendon, and/or vascular blanching of the Achilles tendon produced by conflicting internal and external rotatory forces imparted to the tibia by simultaneous pronation and knee extension. Virtually all cases of Achilles tendon injury appear to result from structural or dynamic disturbances in normal lower leg mechanics and require active treatment regimens which attempt to establish normal function to prevent recurrence.

Effects of hyperbaric oxygen on a human model of injury.

To determine whether intermittent exposures to hyperbaric oxygen enhance recovery from delayed-onset muscle soreness of the quadriceps, we conducted a randomized, controlled, double-blinded, prospective study using 66 untrained men between the ages of 18 and 35 years. After the induction of muscle soreness, these subjects were treated in a hyperbaric chamber over a 5-day period in two phases, with four groups (control, hyperbaric oxygen treatment, delayed treatment, and sham treatment) in the first phase; and three groups (3 days of treatment, 5 days of treatment, and sham treatment) in the second phase. The hyperbaric exposures involved 100% oxygen for 1 hour per day at 2.0 atm. The sham treatments involved 21% oxygen for 1 hour per day at 1.2 atm. We monitored recovery using a leg dynamometer to test eccentric torque of the nondominant quadriceps muscle before and immediately after exercise and at 48 and 96 hours after exercise. Pain was tested daily using visual analog pain scales. In phase 1 a significant difference in recovery of eccentric torque was noted in the treatment group compared with the other groups. In phase 2, the recovery of eccentric torque for the 5-day treatment group was significantly greater than for the sham group from immediately after exercise to 96 hours after exercise. The pain data did not differ significantly in any comparison in either phase. The results suggest that treatment with hyperbaric oxygen may enhance recovery of eccentric torque of the quadriceps muscle from delayed-onset muscle soreness.

Stress fractures in athletes. A study of 320 cases.

We analyzed cases of 320 athletes with bone scan-positive stress fractures (M = 145, F = 175) seen over 3.5 years and assessed the results of conservative management. The most common bone injured was the tibia (49.1%), followed by the tarsals (25.3%), metatarsals (8.8%), femur (7.2%), fibula (6.6%), pelvis (1.6%), sesamoids (0.9%), and spine (0.6%). Stress fractures were bilateral in 16.6% of cases. A significant age difference among the sites was found, with femoral and tarsal stress fractures occurring in the oldest, and fibular and tibial stress fractures in the youngest. Running was the most common sport at the time of injury but there was no significant difference in weekly running mileage and affected sites. A history of trauma was significantly more common in the tarsal bones. The average time to diagnosis was 13.4 weeks (range, 1 to 78) and the average time to recovery was 12.8 weeks (range, 2 to 96). Tarsal stress fractures took the longest time to diagnose and recover. Varus alignment was found frequently, but there was no significant difference among the fracture sites, and varus alignment did not affect time to diagnosis or recovery. Radiographs were taken in 43.4% of cases at the time of presentation but were abnormal in only 9.8%. A group of bone scan-positive stress fractures of the tibia, fibula, and metatarsals (N = 206) was compared to a group of clinically diagnosed stress fractures of the same bone groups (N = 180), and no significant differences were found. Patterns of stress fractures in athletes are different from those found in military recruits. Using bone scan for diagnosis indicates that tarsal stress fractures are much more common than previously realized. Time to diagnosis and recovery is site-dependent. Technetium99 bone scan is the single most useful diagnostic aid. Conservative treatment of stress fractures in athletes is satisfactory in the majority of cases.

Metabolic responses to prolonged work during treadmill and water immersion running.

The primary aim of this study was to compare the physiological responses to prolonged treadmill (TM) and water immersion to the neck (WI) running at threshold intensity. Ten endurance runners performed TM and WI running VO2max tests. Subjects completed submaximal performance tests at ventilatory threshold (Tvent) intensities under TM and WI conditions and responses at 15 and 42 minutes examined. VO2 was lower in WI (p<0.05) at maximal effort and Tvent. The Tvent VO2 intensities interpolated from the TM and WI VO2max tests were performed in both TM (i.e., TM@TM(tvent),TM@WI(tvent), corresponding to 77.6 and 71.3% respectively of TM VO2max) and WI conditions (i.e., WI@TM(tvent), WI@WI(tvent), corresponding to 85.5% and 78.2% respectively of WI VO2max). Each of the dependent variables was analyzed using a 3-way repeated measures ANOVA (2 conditions X 2 exercise intensities X 7 time points during exercise). VO2max values were significantly lower in the WI (52.4(5.1) ml.kg(-1) min(-1)) versus TM (59.7(6.5) ml.kg(-1) min(-1)) condition. VO2 during submaximal tests were similar during the TM and WI conditions. HR and [BLa] responses to exercise at and above WI(tvent) were similar during short-term exercise, but values tended to be lower during prolonged exercise in the WI condition. There were no statistical differences in VE responses in the 2 conditions, however as with HR and [BLa] an upward trend was noted with TM exercise over the 42 minute duration of the tests. RPE at WI(tvent) was similar for TM and WI exercise sessions, however, RPE at TM(tvent) was higher during WI compared to TM running. Cardiovascular drift was observed during prolonged TM but not WI running. Results suggest differences in metabolic responses to prolonged submaximal exercise in WI, however it can be used effectively for cross training.

A guide to the prevention of running injuries.

In North America, estimates of recreational runners have grown from two million in 1970 to 30 million in 1979. In Canada, increased interest in running has been sparked by participation. Habituation to running is attributed to a sense of wellbeing and increased energy levels, as well as the possibility of reducing the threat of cardiovascular disease. Musculoskeletal injury is common to runners and can be prevented by carefully planned training programmes, proper selection of training surface, regular stretching and strength drills, the use of protective footwear and balancing of vulnerable biomechanical alignments with functional orthotics in shoes.