Pre-season Period Research Articles

Intrinsic risk factors of non-contact quadriceps and hamstring strains in soccer: a prospective study of 100 professional players

ObjectivesTo identify the intrinsic risk factors of non-contact strains in the hamstrings and quadriceps muscles of professional soccer players via a cohort prospective design.MethodsA total of 100 professional soccer players...

Training Loads and Incidence of Injury During the Preseason in Professional Rugby League Players

Research into rugby league has found a significant, positive relationship between training load and injury rates. However, there has been limited research investigating this relationship in the preseason period, and the relationship between training load, and injury among professional rugby league players is yet to be examined. The primary aim of this study was to examine the relationships between training load, various psychological data, and the incidence of injury during preseason training at a professional rugby league club. Thirty-six male professional rugby league players undertook a 14-week training program. Each player's training time, intensity rating, and injury status were recorded after each training session. In addition, players rated their sleep, food, energy, mood, and stress on a scale of 1-10 (with 1 being extremely poor and 10 being excellent) biweekly. Over the entire preseason period, a total of 2,877.9 training hours were recorded for the players, with an overall incidence of injury of 6.9 per 1,000 training hours. Higher training loads during the first half of the preseason corresponded to a higher injury rate in comparison to the second half of the preseason. No significant relationship was found between the preseason weekly injury rate and the weekly load, nor was there a relationship between injury and psychological data. These findings suggest no relationship between training load, psychological data, and injury incidence during the preseason training period in professional rugby league players. However, results suggest that players may have an increased risk of injury during the early preseason period. The findings of this study may be particularly useful in professional rugby league teams to determine when a player is at increased risk of injury, using their training loads and psychological data.

EFFECT OF FRUIT BAGGING ON CHEMICAL COMPOSITIONS AND SKIN PIGMENTS OF FRESH LONGAN (DIMOCARPUS LONGAN LOUR.)

The effect of bagging on chemical composition and skin color pigments of fresh longan cv. 'Daw' produced during pre-season, on-season and off-season periods indicated that bagging caused the skin to be more yellowish-green or golden-yellow than control or non-bagged fruits. Bagging of fruits in each period led to changes in the color of fruit rind after the 7 th week of bagging. The amount of chlorophyll, beta-carotene, anthocyanin and phenolic components were found to decrease with time. However, bagging of fruits did not show any significant effect on the chemical compositions of fruit. Bagging of fruits during on-season caused fruits to be much bigger and longer than control fruits while bagging of fruits during off season caused fruits to be smaller and shorter than control fruits and bagging of fruits during pre-season did not affect fruit size. Bagging of fruits during on- and off-season caused lower total soluble solids than that of control fruits, while bagging during pre-season did not significantly affect the total soluble solid content.

Effects of 12-Week On-Field Combined Strength and Power Training on Physical Performance Among U-14 Young Soccer Players

This study examined the effects of on-field combined strength and power training (CSPT) on physical performance among U-14 young soccer players. Players were assigned to experimental (EG, n = 28) and control groups (CG, n = 23). Both groups underwent preseason soccer training for 12 weeks. EG performed CSPT twice a week, which consisted of strength and power exercises that trained the major muscles of the core, upper, and lower body. CSPT significantly (p < 0.05) improved vertical jump height, ball-shooting speed, 10 m and 30 m sprint times, Yo-Yo intermittent endurance run (YYIER), and reduced submaximal running cost (RC). CSPT had moderate effect on vertical jump, ball-shooting, 30 m sprint, and YYIER, small effect on 10 m sprint, RC, and maximal oxygen uptake. YYIER had significant (p < 0.05) correlations with 10 m (r = -0.47) and 30 m (r = -0.43) sprint times, ball-shooting speed (r = 0.51), and vertical jump (r = 0.34). The CSPT can be performed together with soccer training with no concomitant interference on aerobic capacity and with improved explosive performances. In addition, it is suggested that CSPT be performed during the preseason period rather than in-season to avoid insufficient recovery/rest or overtraining.

Pre-seasonal Specific Immunotherapy in rhino-conjunctivitis versus Placebo

RATIONALE: Evaluate the efficacy and safety of specific immunotherapy with grass pollens (SIT) in a blind controlled study with a pre-seasonal treatment during 5 years in patients with seasonal rhino-conjunctivitis. METHODS: We selected 36 patients with rhino-conjunctivitis, who were sensitised to grass pollens, 18 male and 18 female with moderate or severe grade of rhino-conjunctivitis according ARIA. The patients received during 5 years immunotherapy in pre-seasonal period of an extract of 7 grass pollens by sub cutaneous route. All patients received information about forecasts and total pollens count in their residential area. The placebo group had received physiological serum daily in sublingual drops during 7 weeks before spring. The ANOVA test and T test was used for analyse differences between groups and for analyse the correlations the Spearman method was used. RESULTS: A significant improvement was observed regarding symptoms in all patients as in throughout the treatment period in those who specific immunotherapy was performed. The severity of symptoms was smaller in SIT group that in the placebo group. Rescue medication was reduced either in anti-histamine and/or nasal steroids in SIT group with a mean of 23.5 days of medication when compared with the placebo with 61.9 days of medication during the season (p<0.01). The tolerance and safety of immunotherapy was excellent and just in 0.8%. CONCLUSIONS: The short-term and pre-seasonal immunotherapy, subcutaneous for patients sensitised to grass pollens is effective and safety. A considerable reduction of symptoms and reduction in the medication was found. The use of oral anti-histamine drugs and topical steroids was significantly reduced by immunotherapy.

Effects of eccentric exercise on optimum length of the knee flexors and extensors during the preseason in professional soccer players

Objective To assess the effects of eccentric exercise on optimum lengths of the knee flexors and extensors during the preseason in professional soccer. Design Twenty-eight athletes from a professional Spanish soccer team (Division II) were randomly assigned to an eccentric exercise intervention group (EG) or a control group (CG). Over the four-week period two athletes from the control group suffered RF injuries and two athletes were contracted by other clubs. After these exclusions, both groups (EG, n = 13; and CG, n = 11) performed regular soccer training during the four-week preseason period. Results After the four weeks, the optimum lengths of the knee flexors were significantly (P < 0.05) increased by 2.3° in the CG and by 4.0° in the EG. The change in the EG was significantly (P < 0.05) greater than that of the CG. The optimum lengths of the knee extensors were significantly increased only in the EG by 6.5°. Peak torque levels and ratios of quadriceps to hamstring (Q/H ratios) were not significantly altered throughout the study for either group. Conclusion Eccentric exercise can increase the optimum lengths of both the knee extensors and knee extensors flexors during the preseason in professional soccer.

Aerobic capacity and sprint velocity of Leagues I and IV football players

Aerobic capacity and sprint velocity of Leagues I and IV football players Study aim: To assess the aerobic capacity, sprint velocity and changes in biochemical variables in football players preparing for the spring round of matches. Material and methods: Football players from League I (n = 19) and League IV (n = 15) were subjected twice to a graded running tests at the beginning and at the end of the pre-season preparation period. The following variables were recorded: maximum running velocity (km/h), O2max (ml/kg/min), pulmonary ventilation (VE), load at the lactate threshold (LT) expressed as the threshold velocity (LTV; km/h) or %O2max, activities of enzymes in plasma - creatine kinase (CK) and lactate dehydrogenase (LDH), concentrations of lactate (La), ammonia (NH3) and of glucose (Gl) in plasma. At the end of the study the players were also subjected to a 30-m sprint test. Results: In League I players, LT significantly (p&lt;0.05) increased from 11.9 ± 0.8 (at the beginning) to 12.6 ± 0.7 km/h (at the end of the pre-season preparation period) and the maximum load - from 17.4 ± 0.9 to 18.3 ± 1.0 km/h, respectively. Also, the concentrations of NH3 and Gl significantly (p&lt;0.05) increased and enzyme activities tended to increase (p&lt;0.10) following the graded running test. Moreover, they attained significantly (p&lt;0.05) higher velocity at the first 5 m of the 30-m sprint test than their League IV mates. Conclusions: The negligible differences between football players from Leagues I and IV in their aerobic capacity and speed abilities, and the marked distance from world elite players in those indices, call for substantial changes in training strategies and schedules.

Effect of Plyometric Training on Swimming Block Start Performance in Adolescents

This study aimed to identify the effect of plyometric training (PT), when added to habitual training (HT) regimes, on swim start performance. After the completion of a baseline competitive swim start, 22 adolescent swimmers were randomly assigned to either a PT (n = 11, age: 13.1 +/- 1.4 yr, mass: 50.6 +/- 12.3 kg, stature: 162.9 +/- 11.9 cm) or an HT group (n = 11, age: 12.6 +/- 1.9 yr, mass: 43.3 +/- 11.6 kg, stature: 157.6 +/- 11.9 cm). Over an 8-week preseason period, the HT group continued with their normal training program, whereas the PT group added 2 additional 1-hour plyometric-specific sessions, incorporating prescribed exercises relating to the swimming block start (SBS). After completion of the training intervention, post-training swim start performance was reassessed. For both baseline and post-trials, swim performance was recorded using videography (50 Hz Canon MVX460) in the sagital plane of motion. Through the use of Silicon Coach Pro analysis package, data revealed significantly greater change between baseline and post-trials for PT when compared with the HT group for swim performance time to 5.5 m (-0.59 s vs. -0.21 s; p < 0.01) and velocity of take-off to contact (0.19 ms vs. -0.07 ms; p < 0.01). Considering the practical importance of a successful swim start to overall performance outcome, the current study has found that inclusion of suitable and safely implemented PT to adolescent performers, in addition to HT routines, can have a positive impact on swim start performance.

Muscular Power, Neuromuscular Activation, and Performance in Shot Put Athletes At Preseason and at Competition Period

The aim of this study was to investigate changes in shot put performance, muscular power, and neuromuscular activation of the lower extremities, between the preseason and the competition period, in skilled shot put athletes using the rotational technique. Shot put performance was assessed at the start of the pre-season period as well as after 12 weeks, at the competition period, in nine shot putters. Electromyographic (EMG) activity of the right vastus lateralis muscle was recorded during all shot put trials. Maximum squat strength (1RM) and mechanical parameters during the countermovement jump (CMJ) on a force platform were also determined at pre-season and at competition period. Shot put performance increased 4.7% (p < 0.05), while 1RM squat increased 6.5% (p < 0.025). EMG activity during the delivery phase was increased significantly (p < 0.025) after the training period. Shot put performance was significantly related with muscular power and takeoff velocity during the CMJ, at competition period (r = 0.66, p < 0.05 and 0.70, p < 0.05), but not with maximum vertical force. One RM squat was not related significantly with shot put performance. These results suggest that muscular power of the lower extremities is a better predictor of rotational shot put performance than absolute muscular strength in skilled athletes, at least during the competition period.

Physical Performance Characteristics in National Collegiate Athletic Association Division III Champion Female Lacrosse Athletes

The purpose of this study was to examine performance differences between starters and nonstarters and between different playing positions in collegiate female lacrosse athletes. Twenty-two subjects playing on a two-time defending National Champion National Collegiate Athletic Association Division III female lacrosse team volunteered to participate in this study. Subjects were examined during the preseason period and participated in a total of 5 testing sessions, separated by at least 72 hours. Subjects were tested on their 1 repetition maximum (1RM) (bench press and squat), vertical jump, Wingate anaerobic power test (WAnT), 30-second sprint using a nonmotorized treadmill, maximal aerobic capacity, 40-yd sprint, T-drill, and pro-agility test. No significant differences were observed between starters and nonstarters in any performance variable. Anthropometric analysis revealed that attackers were 15.7% (p < 0.05) heavier than midfielders. A significant difference (10.3%) between defenders and midfielders was seen in 1RM squat, while no other strength differences were noted. Attackers were more powerful in the WAnT (both peak and mean power) than both defenders (19.6 and 13.4%, respectively) and midfielders (21.2 and 13.4%, respectively). No significant differences were noted between the groups in any speed or agility measure. Although physical performance characteristics were not different between starters and nonstarters, results indicate that attackers are heavier and more powerful than the other positions and midfielders appear to be weaker in lower-body strength relative to the other positions in lacrosse.

Monitoring Growing Season Length of Deciduous Broad Leaf Forest Derived From Satellite Data in Iran

Problem statement: Leaf phenology describes the seasonal cycle of leaf functioning and is essential for understanding the interactions between the biosphere, the climate and biogeochemical cycles. This study aimed to quantify changes in plant phenology of deciduous broadleaf forests between the years 1982-1999 and investigate the relationships between the onset dates of phenology and climatic factors. Approach: We studied the climate changes effected on the growing season duration in vegetation of Iran, using the AVHRR/NDVI biweekly time-series data collected from 1982-1999 and concurrent mean temperature and precipitation data. The first estimated fastest changes of NDVI corresponded to the vegetation green-up and dormancy from the seasonal cycle of NDVI during 1982-1999. The onset dates of vegetation green-up and dormancy were determined based on the estimated rates and the NDVI seasonal cycles. Results: The results showed that over the study period, the growing season duration has lengthened by 0.94 days year-1 in study region. The green-up of vegetation has advanced in the spring by 0.63 days year-1 and the dormancy delayed in autumn by 0.32 days year-1. The onset date of green-up for all vegetation types negatively correlated with mean preseason temperature for almost all the preseason periods significant, suggesting that the warmer winters probably benefit an earlier green-up the following spring. Conclusion: Based on NOAA/AVHRR NDVI biweekly time-series data and concurrent climate information, it was estimated that the growing season duration of Iran’s vegetation was significantly lengthened, primarily through an earlier green-up and a later dormancy during the period of 1982-1999.

Drinking by professional Australian Football League (AFL) players: prevalence and correlates of risk

To examine self-reported patterns of alcohol consumption and experience of alcohol-related harms among professional Australian Football League (AFL) players. Cross-sectional survey of player alcohol consumption and self-reported alcohol-related harms among members of all 16 professional AFL clubs. Data relating to the 2006 football year were collected between 25 July and 30 August 2006 at regular football training sessions using a self-administered structured questionnaire. Risky/high-risk drinking for long- and short-term harm at different times of the year; Alcohol Use Disorders Identification Test (AUDIT) score. 582 AFL players completed the questionnaire (an 83% response rate). Alcohol consumption varied at different times of the year. During the playing season (approximately 22 weeks), the level of risky/high-risk consumption for long-term harm in AFL players (11/564 [2%]) was typically lower than in age-matched Australian men in the general population (15%). However, risky/high-risk consumption for long-term harm was higher in AFL players during the end-of-season period (approximately 2 weeks) (303/561 [54%]) and vacation period (6-8 weeks) (231/559 [41%]) than in age-matched Australian men. Risky/high-risk drinking for short-term harm on a monthly basis was frequent at all times of the year (eg, 395/560 [71%] in the pre-season period). The mean AUDIT score was 8.8 (95% CI, 8.4 to 9.1; range, 0 to 36). Reports of harmful effects of drinking and negative consequences, such as getting involved in a fight (physical or verbal) while drinking (146/556 [26%]), were common. Risky/high-risk consumption for short-term harm on a monthly basis was associated with a variety of player characteristics, such as usually drinking in public locations (odds ratio, 1.55 [95% CI, 1.02 to 2.35]). AUDIT score was associated with variables such as marital status, with married players scoring more than two points lower (95% CI, - 3.58 to - 0.58) than single players. Formal club rules on alcohol consumption had little effect on outcome measures. Drinking among AFL players is intricately related to time of year. This seasonal drinking pattern requires the development of specific club and league strategies to minimise drinking-related harms to players.

Validity of a Repeated-Sprint Test for Football

Three studies involving 108 football players were conducted to examine the reliability of a repeated-shuttle-sprint ability (RSSA) test and its ability to differentiate between players of various competitive levels and playing positions. Study 1: Short-term reliability was determined in 22 professional players completing the RSSA test (6 x 40-m sprints with 20 s of recovery between sprints) on two separate occasions. Study 2: Long-term reliability (seasonal changes) was examined in 31 professional players completing the RSSA test four times (during the preseason period, at the start, middle and end of the competitive season). Study 3: 108 players were divided and compared according to competitive level or playing position. Standard error of measurement values expressed as coefficient of variation for RSSA mean time and best time were 0.8 and 1.3 % (short-term reliability) and 0.9 and 1.2 % (long-term reliability), respectively. The smallest worthwhile changes were 0.5 % for both mean and best time. Professional players showed better RSSA performance than amateur players, and defenders displayed the lowest RSSA performance. In conclusion, the RSSA test showed adequate construct validity but only RSSA mean time showed sufficient reliability to detect large training-induced changes but not small important differences.

Are injury rates in female volleyball players age related?

The purposes of this study were to record the injury incidence in all age categories of female volleyball players and to clarify the role of age in injury occurrence. The injury incidence rate, severity, diagnosis and the anatomical location of the injuries, which occurred during practice and competition during the championship period, were recorded prospectively during the 2005–2006 period. A total of 689 Greek female volleyball players participating in all volleyball championships in Greece were observed on a weekly basis. The injury incidence rate was recorded as number of injured players and also number of injuries per player-year (total exposure time). No significant differences in injury occurrence rate were observed between the different age categories (youth, junior, senior). Acute injuries were significantly more commonly than overuse syndromes, and the ankle was the most common injured anatomical location. The injury rate in the competitive season was significantly greater than that in the preseason and post-season periods for all the participants. We suggest that any findings in injury occurrence rate must be interpreted in relation to the total exposure time in order to have more realistic conclusions.

Prolonged preseasonal treatment phase with Grazax sublingual immunotherapy increases clinical efficacy

Sublingual immunotherapy treatment with grass allergen tablets (Grazax) is initiated preseasonally without up-dosing and treatment is continued throughout the entire grass pollen season. The influence of the duration of preseasonal treatment on clinical efficacy obtained within the grass pollen season was investigated. Data from three randomized, double-blind, placebo-controlled, multi-centre trials with varying preseasonal treatment periods were analysed. In the grass pollen season, symptom and medication score reductions relative to placebo were calculated and correlated with the duration of the preseasonal treatment period. The analysis was based on data from 934 patients. A significant reduction in seasonal daily rhinoconjunctivitis symptom and medication scores (17%, CI: 1-33% and 23%, CI: 1-47%, P < 0.05) was observed for patients treated with Grazax compared with placebo after approximately 8 weeks of pretreatment. The magnitude of the reductions in rhinoconjunctivitis symptom and medication scores increased with longer duration of preseasonal treatment (P < 0.0001). Sublingual immunotherapy with Grazax) must be initiated at least 8 weeks prior to the grass pollen season to provide a significant clinical efficacy. A longer preseasonal treatment period (>8 weeks) improves the clinical efficacy (relative to placebo) during the grass pollen season.

Changes in numbers of large ovarian follicles, plasma luteinizing hormone and estradiol-17β concentrations and egg production figures in farmed ostriches throughout the year

In this study we described and analysed changes in the numbers of large ovarian follicles (diameter 6.1–9.0 cm) and in the plasma concentrations of luteinizing hormone (LH) and estradiol-17β (E 2β) in relation to individual egg production figures of farmed ostriches ( Struthio camelus spp.) throughout one year. Ultrasound scanning and blood sampling for plasma hormone analysis were performed in 9 hens on a monthly basis during the breeding season and in two periods of the non-breeding season. Our data demonstrated that: (1) large follicles were detected and LH concentrations were elevated already 1 month before first ovipositions of the egg production season took place; (2) E 2β concentrations increased as soon as the egg production season started; (3) numbers of large follicles, LH and E 2β concentrations were elevated during the entire egg production season; and that (4) numbers of large follicles, LH and E 2β concentrations decreased simultaneous with or following the last ovipositions of the egg production season. By comparing these parameters during the egg production season with their pre-and post-seasonal values, significant differences were found in the numbers of large follicles and E 2β concentrations between the pre-seasonal, seasonal and post-seasonal period; while LH concentrations were significantly different between the seasonal and post-seasonal period. In conclusion, our data demonstrate that changes in numbers of large follicles and in concentrations of LH and E 2β closely parallel individual egg production figures and provide some new cues that egg production in ostriches is confined to a marked reproductive season. Moreover, our data provide indications that mechanism, initiating, maintaining and terminating the egg production season in farmed breeding ostriches are quite similar to those already known for other seasonal breeding bird species.

Vitamin C and E Supplementation Effects in Professional Soccer Players Under Regular Training

Exercise training is known to induce an increase in free radical production potentially leading to enhanced muscle injury. Vitamins C and E are well known antioxidants that may prevent muscle cell damage. The purpose of this study was to determine the effects of these supplemental antioxidant vitamins on markers of oxidative stress, muscle damage and performance of elite soccer players. Ten male young soccer players were divided into two groups. Supplementation group (n = 5) received vitamins C and E supplementation daily during the pre-competitive season (S group), while the placebo group (PL group, n = 5) received a pill containing maltodextrin. Both groups performed the same training load during the three-month pre-season training period. Erythrocyte antioxidant enzymes glutathione reductase, catalase and plasma carbonyl derivatives did not show any significant variation among the experimental groups. Similarly, fitness level markers did not differ among the experimental groups. However, S group demonstrated lower lipid peroxidation and muscle damage levels (p < 0.05) compared to PL group at the final phase of pre-competitive season. In conclusion, our data demonstrated that vitamin C and E supplementation in soccer players may reduce lipid peroxidation and muscle damage during high intensity efforts, but did not enhance performance.

Why are older Australian football players at greater risk of hamstring injury?

Increasing age is a commonly identified predictor of hamstring injury but is not modifiable to reduce injury risk. Why increasing age is a risk factor for hamstring injuries in athletes has not been studied to date. This study aimed to identify potentially modifiable age-related changes that predict hamstring injury in a population of Australian football players. One hundred and one young (< or =20 years), and 73 older (> or =25 years), Australian football players, without a history of hamstring injury in the past 12 months were studied prospectively. Players underwent screening of anthropometric, flexibility and lower extremity range of movement tests during the pre-season period and were followed-up for a full season with respect to injury and match participation. Comparisons of the age groups were performed to identify differences related to age. Logistic regression analysis was undertaken to determine whether the observed differences were predictors of hamstring injury. There were significant differences between the age groups with respect to body weight, body mass index, hip flexor flexibility, hip internal rotation and ankle dorsiflexion range of movement. Body weight and hip flexor flexibility were significant independent predictors of hamstring injury in players aged > or =25 years. None of the observed differences were predictors of injury in the younger age group. There are age-related changes that are potentially modifiable to reduce injury risk in older athletes and these factors should be considered in the development of hamstring injury prevention programs for this high risk group.

Lactate threshold responses to a season of professional British youth soccer

Objective: To examine the changes in aerobic endurance performance of professional youth soccer players throughout the soccer season. Methods: Nine youth soccer players were tested at six different time points...

Testing soccer players

To cope with the physiological demands of soccer, players must be competent across several fitness components. The use of fitness tests in the laboratory and field assist in examining soccer players' capabilities for performance both at the amateur and elite levels. Laboratory tests provide a useful indication of players' general fitness. Accurate test results can be obtained with the use of a thorough methodology and reliable equipment. Laboratory tests are used sparingly during the season because of the time-consuming nature of the tests. Instead, tests are generally carried out at the start and end of the pre-season period to evaluate the effectiveness of specific training interventions. Field tests provide results that are specific to the sport and are therefore more valid than laboratory tests. The reduced cost, use of minimal equipment and the ease with which tests can be conducted make them more convenient for extensive use throughout the season. Although data from laboratory and field tests provide a good indication of general and soccer-specific fitness, individual test results cannot be used to predict performance in match-play conclusively because of the complex nature of performance in competition. Fitness tests in conjunction with physiological data should be used for monitoring changes in players' fitness and for guiding their training prescription.