Pre-season Period Research Articles

Injury incidence and distribution in elite football—a prospective study of the Danish and the Swedish top divisions

The Danish and Swedish male top football divisions were studied prospectively from January to June 2001. Exposure to football and injury incidence, severity and distribution were compared between the countries. Swedish players had greater exposure to training (171 vs. 123 h per season, P<0.001), whereas exposure to matches did not differ between the countries. There was a higher risk for injury during training in Denmark than in Sweden (11.8 vs. 6.0 per 1000 h, P<0.01), whereas for match play there was no difference (28.2 vs. 26.2 per 1000 h). The risk for incurring a major injury (absence from football more than 4 weeks) was greater in Denmark (1.8 vs. 0.7 per 1000 h, P = 0.002). The distribution of injuries according to type and location was similar in both countries. Of all injuries in Denmark and Sweden, overuse injury accounted for 39% and 38% (NS), and re-injury for 30% and 24% (P = 0.032), respectively. The greater training exposure and the long pre-season period in Sweden may explain some of the reported differences.

Predictors of hamstring injury at the elite level of Australian football

Hamstring injuries are the most common injury sustained by elite Australian football players and result in substantial costs because of missed training time, unavailability for matches and lost player payments. Evidence to support proposed risk factors for hamstring injury is generally lacking, limiting the development of appropriate prevention strategies. To identify intrinsic risk factors for hamstring injury at the elite level of Australian football. A prospective cohort of 222 players underwent baseline measurement in the form of a self-report questionnaire and a musculo-skeletal screen during the pre-season period of the 2002 Australian football season. Injury surveillance and exposure data were collected for the full season. Logistic regression analyses were used to identify independent predictors of hamstring injury in this group of players. Thirty-one players sustained a hamstring injury. A past history (previous 12 months) of hamstring injury and increasing age were found to be independent predictors of hamstring injury. Older players and those with a previous history of hamstring injury are target groups for further research and implementation of injury prevention strategies. Restricted ankle dorsiflexion range of movement warrants consideration in the development of prevention programs for hamstring injury.

Physiological and Anthropometric Characteristics of Junior Rugby League Players Over a Competitive Season

This study investigated the physiological and anthropometric characteristics of junior rugby league players over a competitive season. Forty-five rugby league players were allocated into training (n = 36) and nonexercise control (n = 9) groups. The training group participated in 2 field-training sessions each week with training loads, match loads, and injury rates recorded. Subjects performed measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), muscular power (vertical jump), speed (10-, 20-, and 40-m sprint), agility ('L run'), and estimated maximal aerobic power (multi-stage fitness test) in December (off-season), March (preseason), May (midseason), and August (end-season). Training loads progressively increased in the general preparatory phase of the season (preseason period), and declined slightly during the competitive phase of the season. Match intensity and match loads decreased throughout the season. Increases in estimated maximal aerobic power and muscular power and reductions in skinfold thickness occurred during the general preparatory phase of the season, and were maintained throughout the competitive phase of the season. These findings suggest that high training loads in the general preparatory phase of the season and low match loads in the competitive phase of the season allow junior rugby league players to maintain a high level of fitness throughout an entire competitive season.

The effect of a professional cricket match schedule on selected immune parameters

Objective. The impact of a professional cricket match schedule on white blood cell (WBC) distribution and lymphocyte activation (CD69 expression) was investigated. Methods. After a 3-month pre-season training period, physical and immune parameters were determined in 14 male cricketers before (B) and after (A) an intensive 5- week match schedule. Results. Exercise test results were unchanged from B to A. Total WBC counts were similar, but total lymphocyte and lymphocyte subpopulation counts decreased significantly. The CD4:CD8 ratio did not change. After in vitro stimulation, percentage CD4+CD69+ cells increased (B: 54.4 ± 9.7%, A: 64.0 ± 8.5%, p &lt; 0.01), but absolute CD4+CD69+ cell counts did not change from B to A. In contrast, both the %CD8+CD69+ cells and absolute CD8+CD69+ cell count remained similar. Conclusion. A strenuous, interregional, professional cricket match schedule resulted in a decreased number of lymphocytes, but relatively increased in vitro reactivity of CD4+ cells, thus maintaining the absolute capacity of the CD4+ cells to become activated on stimulation. In cricketers who suffered upper respiratory tract symptoms during the match schedule (N = 7), none of the immune parameters investigated differed significantly from the others at B or A. SA Sports Medicine Vol.16(2) 2004: 22-27

The effect of a professional cricket match schedule on selected immune parameters

Objective. The impact of a professional cricket match schedule on white blood cell (WBC) distribution and lymphocyte activation (CD69 expression) was investigated. Methods. After a 3-month pre-season training period, physical and immune parameters were determined in 14 male cricketers before (B) and after (A) an intensive 5- week match schedule. Results. Exercise test results were unchanged from B to A. Total WBC counts were similar, but total lymphocyte and lymphocyte subpopulation counts decreased significantly. The CD4:CD8 ratio did not change. After in vitro stimulation, percentage CD4+CD69+ cells increased (B: 54.4 ± 9.7%, A: 64.0 ± 8.5%, p &lt; 0.01), but absolute CD4+CD69+ cell counts did not change from B to A. In contrast, both the %CD8+CD69+ cells and absolute CD8+CD69+ cell count remained similar. Conclusion. A strenuous, interregional, professional cricket match schedule resulted in a decreased number of lymphocytes, but relatively increased in vitro reactivity of CD4+ cells, thus maintaining the absolute capacity of the CD4+ cells to become activated on stimulation. In cricketers who suffered upper respiratory tract symptoms during the match schedule (N = 7), none of the immune parameters investigated differed significantly from the others at B or A. SA Sports Medicine Vol.16(2) 2004: 22-27

Reductions in pre-season training loads reduce training injury rates in rugby league players

Objectives: To investigate if reductions in pre-season training loads reduced the incidence of training injuries in rugby league players, and to determine if the reductions in training loads compromised the...

Effects of Maximal Exercise on Nonspecific Immunity in Athletes under Trained and Detrained Conditions

1755 Very few studies have examined the effect of maximal exercise on nonspecific immunity in athletes under trained and detrained conditions. PURPOSE: To investigate both the acute effects of maximal exercise and the chronic effects of training on nonspecific immunity in winter-sports athletes during different training periods. METHODS: In 15 winter-sports athletes, these acute and chronic effects were investigated during different training periods: (a) in summer, when the athletes were enhancing their aerobic capacity through extensive endurance training; (b) during the winter sports season, in early winter, when both endurance and athletic training were being undertaken; and (c) in spring, when the athletes were resting (detraining for a month). RESULTS: The mean value ± standard deviation) of the maximal oxygen uptake in each of the three training periods (a, b and c) were 65.4 ± 4.6 mL·kg−1·min−1, 63.1 ± 5.5 mL·kg−1·min−1, and 58.3 ± 5.8 mL·kg−1·min−1, respectively. Following maximal exercise, acute peripheral leukocytosis due to lymphocytosis and neutrophila was observed in all three periods. The capacity of isolated and stimulated neutrophils to produce reactive oxygen species as measured by luminol-dependent chemiluminescence (LDCL) was significantly enhanced after maximal exercise before and during the athletic season, but decreased during after-season detraining, suggesting that the conditioning state affected the exercise-induced changes in neutrophil functional status. Serum opsonic activity also showed a similar pattern. As for the chronic effects of training, a significant decline was particularly seen in the resting values of the segmented neutrophil count, the neutrophil LDCL response and the serum IgG level, in the pre-season training period. CONCLUSION: The nonspecific immune status of the subjects might have been partially compromised due to chronic overload while engaged in exhaustive endurance training under heat exposure.

Effects of Maximal Exercise on Nonspecific Immunity in Athletes under Trained and Detrained Conditions

1755 Very few studies have examined the effect of maximal exercise on nonspecific immunity in athletes under trained and detrained conditions. PURPOSE: To investigate both the acute effects of maximal exercise and the chronic effects of training on nonspecific immunity in winter-sports athletes during different training periods. METHODS: In 15 winter-sports athletes, these acute and chronic effects were investigated during different training periods: (a) in summer, when the athletes were enhancing their aerobic capacity through extensive endurance training; (b) during the winter sports season, in early winter, when both endurance and athletic training were being undertaken; and (c) in spring, when the athletes were resting (detraining for a month). RESULTS: The mean value ± standard deviation) of the maximal oxygen uptake in each of the three training periods (a, b and c) were 65.4 ± 4.6 mL·kg−1·min−1, 63.1 ± 5.5 mL·kg−1·min−1, and 58.3 ± 5.8 mL·kg−1·min−1, respectively. Following maximal exercise, acute peripheral leukocytosis due to lymphocytosis and neutrophila was observed in all three periods. The capacity of isolated and stimulated neutrophils to produce reactive oxygen species as measured by luminol-dependent chemiluminescence (LDCL) was significantly enhanced after maximal exercise before and during the athletic season, but decreased during after-season detraining, suggesting that the conditioning state affected the exercise-induced changes in neutrophil functional status. Serum opsonic activity also showed a similar pattern. As for the chronic effects of training, a significant decline was particularly seen in the resting values of the segmented neutrophil count, the neutrophil LDCL response and the serum IgG level, in the pre-season training period. CONCLUSION: The nonspecific immune status of the subjects might have been partially compromised due to chronic overload while engaged in exhaustive endurance training under heat exposure.

Predictors of lower extremity injuries at the community level of Australian football.

To identify risk factors for general lower extremity injury at the community level of Australian football. Prospective cohort study. Community-level Australian football. One hundred twenty-six adult players from 4 community-level Australian football clubs. During the 2000 preseason period, all participants underwent a baseline assessment involving a self-report questionnaire and a battery of musculoskeletal screening tests to collect information about potential risk factors for lower extremity injury. Over the course of the season, injury surveillance and exposure data collection were undertaken at each club. A lower extremity injury, resulting in missed participation and/or treatment from a health professional, as the first injury during the season. For 59 players, a lower extremity injury was the first injury sustained during the season. Only ankle dorsiflexion range of movement, measured using the weightbearing lunge test, was significantly associated with sustaining a lower extremity injury through univariate analyses. Using survival analyses, and after adjusting for exposure, age, frequency of weight training participation, and the past injury status of players were identified as independent, but not significant, predictors of time to sustaining a lower extremity injury. Despite the large number of potential risk factors studied and the high incidence of lower extremity injuries in the cohort, a definitive individual injury risk profile for all lower extremity injuries was not identified, potentially due to the heterogeneity of the outcome of interest. Further research should focus on the identification of risk factors for the most common and costly individual injuries in Australian football.

The Football Association Medical Research Programme: an audit of injuries in professional football—analysis of preseason injuries

Objectives: To conduct a detailed analysis of preseason football injuries sustained in English professional football over two competitive seasons. Methods: Club medical staff at 91 professional football clubs annotated player...

Field evaluation of the Computer Science and Application's Inc. Activity monitor during running and skating training in adolescent athletes.

This study investigated the validity of the CSA activity monitor for assessment of the total amount of physical activity in adolescent athletes. Activity data were compared to data on daily energy expenditure and its derivatives measured by the doubly labeled water method. Seven athletes (speed skaters) with a mean age of 18.2+/-1.1 y were monitored twice (off-season and pre-season) by the activity monitor for eight consecutive days. The primary training during the off-season period was running whereas the pre-season period mainly involved skate training (i.e. inline skating, slideboard training, and skating imitations). Activity counts were significantly correlated to all energy estimates during the off-season period (r=0.93-0.96; P<0.01) whereas not during the pre-season period (r=0.32-0.57). A two-way multivariate analysis of variance showed a significant period effect for activity counts (668+/-163 vs. 548+/-91; P=0.026) whereas not for total daily energy expenditure (15.7+/-2.1 MJ x d(-1) vs. 16.0+/-1.0 MJ x d(-1); P=0.71). The relationship between activity counts and total daily energy expenditure seems to be affected by different training conditions. Therefore these circumstances have to be carefully considered in the interpretation of activity monitor data.

EFFECTS OF MAXIMAL EXERCISE ON NONSPECIFIC IMMUNITY IN ATHLETES UNDER TRAINED AND DETRAINED CONDITIONS

We investigated both the acute effects of maximal exercise and the chronic effects of training on nonspecific immunity in 15 winter-sports athletes during different periods of training : (a) before the athletic season, in summer, when the athletes were undertaking extensive endurance training to enhance aerobic capacity, (b) during the winter sports season, in early winter, when endurance and athletic training were being undertaken, and (c) after the winter sports season, in spring, when the athletes were resting (detraining for a month) . The mean value of the maximal oxygen uptake in each training period was (a) 65.4 (SD 4.6) mL·kg-1·min-1, (b) 63.1 (SD 5.5) mL· kg-1·min-1, and (c) 58.3 (SD 5.8) mL·kg-1·min-1, respectively. Following maximal exercise, acute peripheral leukocytosis due to lymphocytosis and neutrophila was observed in every period. The capacity of isolated neutrophils to produce reactive oxygen species upon stimulation with opsonized zymosan measure by luminol-dependent chemiluminescence (LDCL) was significantly enhanced after maximal exercise before and during the athletic season. However, the degree of enhancement was smaller during after-season detraining, suggesting that the conditioning state affected the exercise-induced changes in neutophil functional status. Serum opsonic activity also showed a similar pattern. As for the chronic effects of training, the resting values of the neutrophil count, especially the segmented neutrophil count, the neutrophil LDCL response and the serum IgG level, declined significantly in the pre-season training period. Since the subjects were engaged in exhaustive endurance training under heat exposure at that time, the nonspecific immune status might have been partially compromised due to chronic overload.

Soccer injuries in Iceland

We investigated the frequency, cause and location of injuries in Icelandic elite soccer in 1991. The incidence of injuries for the individual player was 34.8 +/- 5.7 per 1000 game-hours and 5.9 +/- 1.1 per 1000 practice-hours. The most common types of injuries were muscle strains (29%), ligament sprains (22%), contusions (20%), and other injuries (29%). The frequency of reinjury was markedly high, where 44% of the strains and 58% of the sprains were registered as reinjuries. Strains occurred mainly during sprinting, sprains by tackling, and contusion during other contact. Significantly more injuries occurred on artificial turf than on grass or gravel in correlation to number of hours in games and practices. Teams who had the longest pre-season preparation period obtained significantly fewer injuries during the season.

A reduction in allergen-induced FcϵR2/CD23 expression on peripheral B cells correlates with successful hyposensitization in grass pollinosis

Background: The cellular basis for the mechanism of specific hyposensitization is still unclear. Objective: We prospectively studied the effect of immunotherapy on allergen-induced proliferation and FcϵR2/CD23 expression of lymphocytes. Methods: Mononuclear cells prepared from the peripheral blood of 22 patients with grass pollen (GP) allergy before, during, and after a preseasonal immunotherapy period with GP were stimulated with GP or control antigens. Tritiated thymidine uptake and percentage of CD23 +B cells were determined daily during days 6 to 8 and compared with lymphocyte responsiveness of 11 only symptomatically treated atopic patients and 14 nonatopic individuals. Results: GP-induced lymphocyte proliferative response of both hyposensitized and symptomatically treated GP-allergic patients decreased markedly before the pollen season and rose again after seasonal allergen exposure, whereas a long-lived decrease in GP-induced FcϵR2/CD23 + B cells was only observed in GP-treated patients. Alterations in FcϵR2/CD23 expression were closely related to changes in symptoms and medication requirement during the following pollen season. In contrast, immunotherapy had no effect on FcϵR2/CD23 expression of B cells without stimulation or on B cells cultured in the presence of control antigens. Conclusion: Because FcϵR2/CD23 expression on B cells is antagonistically regulated by the cytokines interleukin-4 and interferon-γ, the decrease of allergen-induced FcϵR2/CD23 + B cells indicates an altered cytokine secretion pattern of the allergen-specific T lymphocytes with a predominance of interferon-γ. (J A LLERGY C LIN I MMUNOL 1995;95:77-87.)

花粉症へのエメダスチンの予防，治療効果 多施設による二重盲検群間比較試験

To evaluate the effectiveness, safety and utility of Emedastine difumarate (ED) in the treatment of Japanese cedar pollinosis, a multicentered, double-blind comparative study was performed in 290 patients in 1994.Patients with Japanese cedar pollinosis were divided into two groups; the first group was treated with ED at a dose of 4mg/day starting two weeks before the season and continuing for the whole season. The second group was given an inactive placebo instead of ED during the pre-season and the early portion of the season and then replaced with ED during the later portion of the season.As a result, the final improvement rate was significantly higher in the first group than that in the second group.All subjective symptoms such as sneezing, nasal discharge, nasal obstruction and eye itching were suppressed due to ED treatment.In conclusion, it was better to continuously administer ED to patients with pollinosis from the preseasonal period till the end of the season.However, when the ED treatment was started in the midseason, the outcome was good, although less satisfactory than the outcome of continuous treatment given throughout the entire pollen season.

Optimum Sample Size Allocation for Wood Duck Banding Studies

Although banding programs are the most important source of information for monitoring the status of wood duck (Aix sponsa) populations, banding quotas generally have not been achieved during the preseason period. LeMaster and Trost (1994) developed a model that accommodated banding during an early period (15 Apr-30 Jun) in addition to the traditional preseason period (1 Jul-15 Sep). Their analysis of existing band recovery data showed that precision of survival and recovery rates for wood duck populations was increased by inclusion of early banded birds. My objective was to develop statistical methodology for computing optimum allocation of effort in the 2 banding periods and to apply this methodology to banding programs for wood ducks

Public health in London

<b>Objectives:</b> To conduct a detailed analysis of preseason football injuries sustained in English professional football over two competitive seasons. <b>Methods:</b> Club medical staff at 91 professional football clubs annotated player injuries. A specific injury audit questionnaire was used together with a weekly form that documented each club’s current injury status. <b>Results:</b> 17% (1025) of the total number of injuries over the two seasons were sustained during the preseason, the mean number of days absent per injury was 22.3 days. Younger age groups (17–25 yrs) were more likely to sustain a preseason injury than more experienced players (26–35+) (p&lt;0.01). There were relatively more “slight” and “minor” injuries (as defined in the methodology), overuse, and tendon related injuries sustained during preseason compared to the in season (p&lt;0.01). The thigh (23%), knee (17%), and ankle (17%) were the most common locations for injuries during the preseason, there was a relatively greater number of lower leg injuries (15%) during the preseason (p&lt;0.05). Achilles tendonitis was most prevalent in the preseason, with 33% of all Achilles related injuries sustained during this period (p&lt;0.01). Muscle strains were the most common injury during preseason (37%). Rectus femoris muscle strains were observed twice as frequently during the preseason relative to the in season (p&lt;0.01). Ligament sprains were the second most common injury during preseason (19%). Non-contact mechanisms were the cause of significantly more injuries during the preseason (p&lt;0.01), with relatively more preseason injuries sustained while running or shooting (p&lt;0.01). For 70% of the injuries reported during the preseason, the ground condition was described as dry. <b>Conclusions:</b> Players are at a greater risk of slight and minor injuries, overuse injuries, lower leg injuries (especially the Achilles tendon) and rectus femoris strains during the preseason period. Prevention of preseason injury is important to ensure availability of players for the commencement of the season and to decrease the risk of injury later in the season, we recommend the implementation of a risk management policy for this purpose. Areas requiring further investigation include methods of prevention for the common preseason injuries that have been identified, a detailed analysis of preseason and closed season training programmes, and a smaller study involving exposure data.

Lymphocyte transformation by grass pollen allergens: a study of atopic patients receiving immunotherapy. Part II. Patients during maintenance treatment.

We have previously reported on peripheral blood lymphocyte (PBL) transformation by allergen, PPD as a control antigen and PHA as a mitogen during and after a preseasonal immunotherapy period. The present report describes similar parameters during and after the ensuing maintenance treatment period. Ten patients with grass pollen rhinitis were treated with Allpyral extract and 10 with Conjuvac two-grass mixture. Lymphocyte transformation responses to grass antigen continued to be low for PBL from patients during the maintenance treatment. Postseasonal values were higher during treatment. In late autumn 1980, when treatment had been stopped, there was a spontaneous fall in lymphocyte stimulation values. Occasional high values were noticed in some patients, two of whom had treatment side effects (urticaria). Clinical data during the whole treatment period (skin prick test, provocation tests, serological parameters, total IgE, grass-specific IgE, grass-specific IgG, pollen counts, symptom scores, clinical effect and adverse reactions) have been published separately.

Injuries in elite orienteers.

A prospective study of injuries in 89 elite orienteers showed a total incidence of three injuries per 1,000 training hours, with no difference between the sexes. Mean absence from training per year due to injury was 20 days for men and 19 days for women. Most injuries (80.3%) occurred during training, while the remaining injuries occurred during competition. The lower extremities were affected in 93.6% of the male injuries and in all of the female injuries. The majority of injuries (60.6%) were moderate, while 19.7% were minor and 19.7% were major injuries. Overuse injuries accounted for 57%; 43% of the injuries were due to trauma. Overuse injuries predominated in the preseason period, while the incidence was equal between overuse and traumatic injuries over the rest of the year. Of a total number of 38 overuse injuries, 60.5% occurred during running on tracks or roads. Thirteen injuries (19.7%) were major; the majority (84.6%) of these injuries were due to overuse, affecting the knee in eight cases (61.5%). Of the major injuries, 76.5% occurred during the period December to May. Of a total number of 28 traumatic injuries, 78.6% occurred while running on uneven ground, mainly in forests. Among the traumatic injuries, ankle sprains accounted for 57.1%, equally distributed between the sexes. The majority of these sprains (81.2%) were moderate. This paper will discuss injury mechanisms and possibilities of prevention.

Biochemical components of stallion seminal plasma before and after the breeding season

Seasonal and breed differences were determined for glyceryl-phosphoryl-choline (GPC), ergothioneine (EGT), fructose and total protein in the seminal plasma of 24 stallions from three breed groups. Significant differences were found between the GPC, EGT, fructose and total protein levels before and after the breeding season. During the post-breeding period, the concentrations of EGT, fructose and total protein increased more than 100% while that for GPC decreased by about 50%. This phenomenon was found in each of the breed groups investigated. Breed differences in the GPC level during the pre- and post-seasonal periods were not significant. Differences were found only during the pre-seasonal period in EGT, fructose and total protein levels.