Nader Rahnama

The Effects of Comprehensive Warm-Up Programs on Proprioception, Static and Dynamic Balance on Male Soccer Players

Purpose The study investigated the effects of FIFA 11+ and HarmoKnee, both being popular warm-up programs, on proprioception, and on the static and dynamic balance of professional male soccer players. Methods Under 21 year-old soccer players (n = 36) were divided randomly into 11+, HarmoKnee and control groups. The programs were performed for 2 months (24 sessions). Proprioception was measured bilaterally at 30°, 45° and 60° knee flexion using the Biodex Isokinetic Dynamometer. Static and dynamic balances were evaluated using the stork stand test and Star Excursion Balance Test (SEBT), respectively. Results The proprioception error of dominant leg significantly decreased from pre- to post-test by 2.8% and 1.7% in the 11+ group at 45° and 60° knee flexion, compared to 3% and 2.1% in the HarmoKnee group. The largest joint positioning error was in the non-dominant leg at 30° knee flexion (mean error value = 5.047), (p<0.05). The static balance with the eyes opened increased in the 11+ by 10.9% and in the HarmoKnee by 6.1% (p<0.05). The static balance with eyes closed significantly increased in the 11+ by 12.4% and in the HarmoKnee by 17.6%. The results indicated that static balance was significantly higher in eyes opened compared to eyes closed (p = 0.000). Significant improvements in SEBT in the 11+ (12.4%) and HarmoKnee (17.6%) groups were also found. Conclusion Both the 11+ and HarmoKnee programs were proven to be useful warm-up protocols in improving proprioception at 45° and 60° knee flexion as well as static and dynamic balance in professional male soccer players. Data from this research may be helpful in encouraging coaches or trainers to implement the two warm-up programs in their soccer teams.

Bilateral and unilateral asymmetries of isokinetic strength and flexibility in male young professional soccer players.

This study investigated bilateral and unilateral asymmetries of strength and flexibility in male young professional soccer players. Thirty-six soccer players (age: 18.9 ± 1.4 years) participated in this study. A Biodex Isokinetic Dynamometer was used to assess the hamstring and quadriceps strength at selected speeds of 60°/s, 180°/s and 300°/s. Hip joint flexibility was measured using a goniometer. No difference was observed in conventional strength ratio, dynamic control ratio and fast/slow speed ratio between the dominant and non-dominant legs (p>0.05). All but one of the players (97.2%) had musculoskeletal abnormality (bilateral imbalance > 10%) in one or more specific muscle groups. The dominant leg had greater hip joint flexibility compared with the non-dominant leg (108.8 ± 10.7° versus 104.6 ± 9.8°, respectively). The findings support the hypothesis that physical performance and movement pattern experienced during soccer playing may negatively change the balance of strength in both legs (bilateral strength balance), but not on the same leg of the young male professional soccer players. The results can be helpful for trainers and coaches to decide whether the players need to improve their balance and strength which in turn may prevent injury. It is suggested that in professional soccer training, quadriceps and hamstrings muscle strength, as well as hip joint flexibility should not be overlooked.

The Effects of Injury Preventive Warm-Up Programs on Knee Strength Ratio in Young Male Professional Soccer Players

Purpose We aimed to investigate the effect of FIFA 11+ (11+) and HarmoKnee injury preventive warm-up programs on conventional strength ratio (CSR), dynamic control ratio (DCR) and fast/slow speed ratio (FSR) in young male professional soccer players. These ratios are related to the risk of injury to the knee in soccer players. Methods Thirty-six players were divided into 3 groups; FIFA 11+, HarmoKnee and control (n = 12 per group). These exercises were performed 3 times per week for 2 months (24 sessions). The CSR, DCR and FSR were measured before and after the intervention. Results After training, the CSR and DCR of knee muscles in both groups were found to be lower than the published normal values (0.61, 0.72, and 0.78 during 60°.s−1, 180°.s−1 and 300°.s−1, respectively). The CSR (60°.s−1) increased by 8% and FSR in the quadriceps of the non-dominant leg by 8% in the 11+. Meanwhile, the DCR in the dominant and non-dominant legs were reduced by 40% and 30% respectively in the 11+. The CSR (60°.s−1) in the non-dominant leg showed significant differences between the 11+, HarmoKnee and control groups (p = 0.02). As for the DCR analysis between groups, there were significant differences in the non-dominant leg between both programs with the control group (p = 0.04). For FSR no significant changes were found between groups. Conclusions It can be concluded that the 11+ improved CSR and FSR, but the HarmoKnee program did not demonstrate improvement. We suggest adding more training elements to the HarmoKnee program that aimed to enhance hamstring strength (CSR, DCR and FSR). Professional soccer players have higher predisposition of getting knee injuries because hamstring to quadriceps ratio were found to be lower than the average values. It seems that the 11+ have potentials to improve CSR and FSR as well as prevent knee injuries in soccer players.

Effect of combination exercise training on metabolic syndrome parameters in postmenopausal women with breast cancer

CONTEXT Studies have shown that physical activity or exercise training may decrease the metabolic syndrome. AIM The aim of the present study is to clarify the effect of combination exercise training on metabolic syndrome parameters in postmenopausal women with breast cancer. SETTING AND DESIGN Twenty nine postmenopausal women (58.27 +/- 6.31 years) with breast cancer were divided into two groups randomly as experimental group (n=14) and control group (n=15). MATERIALS AND METHODS Subjects of experimental group were performed 15 weeks combination exercise training including walking (2 sessions per week) and resistance training (2 sessions per week that was different from walking days). Before and after 15 weeks, fasting insulin and glucose, insulin resistance, high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) were calculated. Also, Vo2peak, rest heart rate (RHR), systolic blood pressure (SBP), body weight (BW), body mass index (BMI) and waist to hip ratio (WHR) were measured in two groups. STATISTICAL ANALYSIS USED Mean values of two groups in pre and post test were compared by independent and paired t-test for all measurements (P ≤ 0.05). RESULTS Significant differences were observed for VO2peak, RHR, BW, BMI, WHR, SBP, fasting insulin and glucose, HDL-C and TG between experimental and control groups after 15 weeks (P< 0.05). CONCLUSIONS Combination exercise training can improve metabolic syndrome parameters in postmenopausal women with breast cancer.

THE EFFECTS OF INJURY PREVENTION WARM-UP PROGRAMMES ON KNEE STRENGTH IN MALE SOCCER PLAYERS

The study investigates the effects of the 11+ and HarmoKnee injury prevention programmes on knee strength in male soccer players. Under-21-year-old players (n=36) were divided equally into: the 11+, HarmoKnee and control groups. The programmes were performed for 24 sessions (20-25 min each). The hamstrings and quadriceps strength were measured bilaterally at 60°·s-1, 180°·s-1 and 300°·s-1. The concentric quadriceps peak torque (PT) of the 11+ increased by 27.7% at 300°·s-1 in the dominant leg (p<0.05). The concentric quadriceps PT of HarmoKnee increased by 36.6%, 36.2% and 28% in the dominant leg, and by 31.3%, 31.7% and 20.05% at 60°·s-1, 180°·s-1 and 300°·s-1 in the non-dominant leg respectively. In the 11+ group the concentric hamstring PT increased by 22%, 21.4% and 22.1% at 60°·s-1, 180°·s-1 and 300°·s-1, respectively in the dominant leg, and by 22.3%, and 15.7% at 60°·s-1 and 180°·s-1, in the non-dominant leg. In the HarmoKnee group the hamstrings in the dominant leg showed an increase in PT by 32.5%, 31.3% and 14.3% at 60°·s-1, 180°·s-1 and 300°·s-1, and in the non-dominant leg hamstrings PT increased by 21.1% and 19.3% at 60°·s-1 and 180°·s-1 respectively. The concentric hamstrings strength was significantly different between the 11+ and control groups in the dominant (p=0.01) and non-dominant legs (p=0.02). The HarmoKnee programme enhanced the concentric strength of quadriceps. The 11+ and HarmoKnee programmes are useful warm-up protocols for improving concentric hamstring strength in young professional male soccer players. The 11+ programme is more advantageous for its greater concentric hamstring strength improvement compared to the HarmoKnee programme.

Acute effects of aerobic and resistance exercises on serum leptin and risk factors for coronary heart disease in obese females

Six young obese females (20.5±1.22 years; BMI=34.5±4.3 kg/m2) participated in a resistance exercise (RE) protocol (12 exercises, 4 sets × 15 repetitions at 60% of 1RM), an aerobic exercise (AE) protocol (3 sets × 10 min ergometer cycling at 60% of maximal heart rate with 5 min of rest between sets), and a control session. Blood samples were collected before, and immediately after and 10 h after exercise. All protocols were done in follicular phase of the menstrual cycle. ANOVA (3×3) with repeated measure on exercise (3 levels) and time (3 levels) factors was used to determine the effects of exercise protocol, time and exercise protocol by blood sampling time interaction, triglycerides, HDL-cholesterol, LDL-cholesterol, and glucose concentrations. Immediately and 10 h after AE, serum leptin was significantly lower (p<0.05). Serum insulin after AE was lower than after RE and control sessions (p<0.05). Furthermore, no significant differences were found in serum leptin and insulin between RE and control sessions immediately after and 10 h after exercise. Blood glucose, triglycerides, total cholesterol, HDL-cholesterol and LDL-cholesterol were unchanged in both exercise protocols. In conclusion, AE resulted in a serum leptin reduction and suppressed the circadian rhythm of serum insulin when sampled immediately and 10 h after exercise; instread, RE did not result in serum leptin or insulin changes.

Effectiveness of Injury Prevention Programs on Developing Quadriceps and Hamstrings Strength of Young Male Professional Soccer Players

Abstract Muscular strength is an important factor which is crucial for performance and injury prevention in most sports. The purpose of this study was to evaluate the effects of the FIFA’s Medical Assessment and Research Centre 11+ and HarmoKnee injury prevention programs on knee strength of young professional male soccer players. Thirty-six soccer players (age: 18.9 ± 1.4 years) were divided equally into three groups; the 11+, HarmoKnee and control groups. The programs were performed for 24 sessions. Hamstring and quadriceps strength was measured using the Biodex System 3 at 30°, 60° and 90° of knee flexion. The 11+ increased quadriceps strength in the dominant leg by 19.7% and 47.8% at 60°and 90° knee flexion, respectively, and in the non-dominant leg by 16%, 35.3% and 78.1 % at 30°, 60° and 90° knee flexion, respectively. The HarmoKnee group, however, showed increased quadriceps strength only at 90° i.e., by 85.7% in the dominant leg and 73.8% in the non-dominant leg. As for hamstring strength, only the 11+ group demonstrated an increment by 24.8% and 19.8% at 30° and 60° knee flexion in the dominant leg, and in the nondominant leg, by 28.7% and 13.7% at 30° and 60° knee flexion, respectively. In conclusion, both warm-up programs improve quadriceps strength. The 11+ demonstrated improvement in hamstring strength while the HarmoKnee program did not indicate any improvement. We suggest adding eccentric hamstring components such as Nordic hamstring exercise to the HarmoKnee program in order to enhance hamstring strength.

The epidemiology of knee injuries in Iranian male professional soccer players

Detailed injury epidemiology is an invaluable tool for minimising risk associated with sporting injuries. The aim of this study was to investigate epidemiology of knee injuries in Iranian male professional soccer players. In total, 390 soccer players of 16 clubs were studied during one season. A total of 43 injured soccer players were interviewed and 16 team physicians were consulted. All information was collected through standard questionnaires. Furthermore, medical personal prospectively reported time-loss injuries sustained by players over one season and the knee injuries were evaluated. The results showed that in total, from 390 players, 43 of them suffered knee injuries (14.9 per 100 players). The anterior cruciate ligament was the most commonly injured ligament of the knee, in which 12.5% were accompanied by injuries to the medial meniscus and medial collateral ligament. There was a significant difference in incidence of injury between the preferred (62.9%) and non-preferred leg (37.1%). Most injuries were characteristically severe (82.3%). Most injuries occurred in away games (52.94%), mostly in the second half and most commonly in the final 15 min (35.3%). The incidence of non-contact injuries (66.12%) was significantly higher than contact injuries (33.87%). It can be concluded that the incidence of knee injury was high (0.12 injuries per team per match). Injury tends to be more common in match play and mostly at the end of season. Midfielders suffered more knee injuries. Most injuries occurred in the losing teams.

The acute effects of two energy drinks on endurance performance in female athlete students

Energy drinks have gained popularity among athletes. The purpose of this study was to determine the acute effects of Phantom and Dragon energy drinks on endurance performance. For this reason 12 female athlete students of Tehran University (age 22±0.63 years, height 162.1±5.8 cm, weight 56.91±6.79 kg) volunteered and performed three sessions on a Bruce treadmill test four days apart from each other. In each session, in a randomised, placebo-controlled, counterbalanced and double-blind design 6 ml/kg body weight of Phantom, Dragon or placebo was consumed 40 min before an exercise test. Using a 3×3 repeated measures analysis of variance and Least Significant Difference (LSD), a significant increase in VO2max time to exhaustion and a decrease in post-test rating of perceived exertion was found for Phantom and Dragon vs. placebo (p<0.05). No significant difference was observed in pre-test hear rate for three drinks (p>0.05). Post-test hear rate increased significantly for Dragon vs. Phantom and placebo (p<0.05). In conclusion, two commercially available energy drinks had ergogenic effects on endurance performance.

Association between bone mass and injuries in professional jumpers

The health benefits of exercise are well established. Research has shown that exercise has a positive effect on bone health. Sport injuries are associated with several physical and physiological changes that lead to increased disability. Examples of these changes are deteriorations in bone and muscle tissues, referred, respectively, as osteopenia and sarcopenia. High peak bone mass in early adulthood is an important protective factor against osteoporotic fractures in later life, but relation between bone mass and sports injuries has been less documented. The main aim of this study was to determine the association between femoral neck, trochanter and lumbar spines bone mineral density (BMD) and bone mineral content (BMC) and injuries in professional jumpers. Thirty professional men jumpers (10 long, 10 high and 10 triple jumpers) with no history of bone disease participated in this study (mean±SD, aged 21.27±3.52 years, height 182±6 cm, weight 69.93±6.01 kg). BMD and BMC of femoral neck, trochanter for right and left sides and also lumbar spines were measured by dual-energy x-ray absorptiometry. Injury data of these professional jumpers over a 1-year time period (2008–2009) were collected using a standard questionnaire retrospectively. Data were analysed using Pearson correlation test. Results of this study showed an indirect but non-significant correlation between BMD and bone-related injuries (r=0.306, p>0.05). A significant negative association between BMC and bone-related injuries was observed (r=0.359, p<0.05). There were no significant correlations between BMD or BMC and ligamentous, muscular and tendinous injuries (r=0.123, p>0.05; r=0.264, p>0.05), respectively. It can be concluded that long time jumping results in high BMC and decreased risk of bone-related injuries in elite jumpers.