The Effects of Injury Prevention Warm-Up Programs on Knee Strength in Male Soccer Players (original) (raw)
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The Effects of Injury Prevention Warm-Up Programmes on Knee Strength in Male Soccer Players
Biology of Sport, 2013
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.
Abdolhamid Daneshjoo 1, Nader Rahnama 2, Abdul Halim Mokhtar 3, Ashril Yusof 4 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 non-dominant 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. Key words: knee, strength, professional soccer player, the 11+, HarmoKnee.
International Journal of Sports Physical Therapy, 2017
Background: Anterior cruciate ligament injury is higher in soccer athletes as compared to athletes of other sports. Risk factors for anterior cruciate ligament injury include low knee hamstring/quadriceps strength ratio and bilateral strength deficits. Purpose: To investigate isokinetic thigh muscles strength, hamstring/quadriceps strength ratio, and bilateral strength comparisons in athletes who participate in professional soccer, futsal, and beach soccer. Study Design: Cross-sectional study. Methods: Brazilian professional soccer (n=70), futsal (n=30), and beach soccer (n=12) players were isokinetically assessed to examine strength of knee extensors and flexors at 60 degrees/second in concentric mode, to measure peak torque of dominant and non-dominant limbs. Results: In the dominant limb, for extensors muscles, futsal players presented significantly lower peak torque values (223.9±33.4 Nm) than soccer (250.9±43.0 Nm; p=0.02) and beach soccer players (253.1±32.4 Nm; p=0.03). Peak torque for extensor muscles in the non-dominant limb was significantly lower in futsal (224.0±35.8 Nm) than in beach soccer players (256.8±39.8 Nm; p=0.03). Hamstring/quadriceps strength ratio for dominant limbs for futsal (57.6±10.1%), soccer (53.5±8.8%), and beach soccer (56.3±8.4%) players presented no significant differences between groups; however, the mean values were lower than recommended values found in the literature. There were no strength deficits for any of the evaluated groups when compared bilaterally. Conclusions: Futsal athletes presented lower values for quadriceps strength than soccer and beach soccer athletes. Futsal, soccer, and beach soccer players presented no strength asymmetries, but they presented with strength imbalance in hamstring/quadriceps strength ratio.
Prevention of hamstring strains in elite soccer: an intervention study
Scandinavian Journal of Medicine & Science in Sports, 2007
The purpose was to test the effect of eccentric strength training and flexibility training on the incidence of hamstring strains in soccer. Hamstring strains and player exposure were registered prospectively during four consecutive soccer seasons (1999)(2000)(2001)(2002) for 17-30 elite soccer teams from Iceland and Norway. The first two seasons were used as baseline, while intervention programs consisting of warm-up stretching, flexibility and/or eccentric strength training were introduced during the 2001 and 2002 seasons. During the intervention seasons, 48% of the teams selected to use the intervention programs. There was no difference in the incidence of hamstring strains between teams that used the flexibility training program and those who did not [relative risk (RR) 5 1.53, P 5 0.22], nor was there a difference compared with the baseline data (RR 5 0.89, P 5 0.75). The incidence of hamstring strains was lower in teams who used the eccentric training program compared with teams that did not use the program (RR 5 0.43, P 5 0.01), as well as compared with baseline data for the same intervention teams (RR 5 0.42, P 5 0.009). Eccentric strength training with Nordic hamstring lowers combined with warm-up stretching appears to reduce the risk of hamstring strains, while no effect was detected from flexibility training alone. These results should be verified in randomized clinical trials.
Journal of sports science & medicine, 2012
Muscle strength imbalance can be an important factor in hamstrings muscle strain. A hamstrings/quadriceps (H/Q) strength ratio based on concentric peak torque values (Hcon:Qcon) has traditionally been used to describe the potential for knee-joint destabilization. Because certain standard actions in soccer are explosive, the analysis of the H/Q strength ratio based on the rate of torque development (Hrtd:Qrtd) might also be useful in the evaluation of joint stability. The objective of this study was to compare the Hrtd:Qrtd between professional soccer players with heterogeneous values of Hcon:Qcon. Thirty-nine professional soccer players took part in the following procedures on different days: 1) Familiarization session with the isokinetic dynamometer, and 2) Two maximal isometric actions and five maximal concentric actions at 60°·s(-1) for hamstrings (H) and quadriceps (Q). Participants were ranked according to their Hcon:Qcon ratio. The median third was excluded to form a high torq...
Hamstring Injury Prevention in Soccer: Before or After Training?
We examined the effects of a 12-week program of Nordic hamstring exercises (NHE), administered before or after football training, upon eccentric hamstring strength, muscle activity, and architectural adaptations. Amateur soccer players were randomized into 3 groups. The control group (CON; n=11) undertook core stability exercises, whereas a periodized NHE program was delivered either before (NHE BEF ; n=10) or after (NHE AFT ; n=14) bi-weekly training sessions. Outcome measures included peak torque and concomitant normalized peak surface electromyography signals (sEMG) of the biceps femoris (BF) and medial hamstring (MH) muscles during knee flexor maximal eccentric contractions, performed at 30°·s -1 . Ultrasonography was used to determine BF muscle thickness, muscle fiber pennation angle, and fascicle length. Performing the NHE derived likely moderate peak torque increases in both NHE BEF (+11.9%; 90% confidence interval: 3.6% to 20.9%) and NHE AFT (+11.6%; 2.6% to 21.5%) versus CON. Maximum sEMG increases were moderately greater in the BF of both NHE training groups versus CON. There were likely moderate increases in BF muscle thickness (+0.17 cm; 0.05 cm to 0.29 cm) and likely small pennation angle increases (+1.03°; -0.08° to 2.14°) in NHE AFT versus CON and NHE BEF . BF fascicle length increases were likely greater in NHE BEF (+1.58 cm; 0.48 cm to 2.68 cm; small effect) versus CON and NHE AFT . A 12-week eccentric hamstring-strengthening program increased strength and sEMG to a similar magnitude irrespective of its scheduling relative to the football training session. However, architectural adaptations to support the strength gains differed according to the timing of the injury prevention program.
Journal of sports science & medicine , 2013, 11
The purpose of this study was to examine the effects of the 11+ and HarmoKnee warm-up programs on performance measures in professional soccer players. Thirty-six male professional soccer players (age: 18.9 ± 1.4 years) were divided into 3 groups, the 11+, HarmoKnee and control group (n = 12 per group). The experimental groups performed the programs 3 times per week for 2 months (24 sessions), whereas the control group only performed their regular soccer training. The performance tests carried out were: 10m speed tests with and without a ball, 20m single sprint, vertical jump, Wall-Volley and Illinois agility tests. The 11+ group demonstrated significant increases from pre-to-post time points in the vertical jump (3.7%), Wall-Volley (5.4%) and Illinois agility tests (1.7%), while the HarmoKnee group showed a significant increase in Wall-Volley test, with a 5.2% increase. The repeated measures analysis revealed differences between the groups (large effect size) in the 11+ and HarmoKnee groups, compared to the control group, in 10m speed tests with and without a ball, 20m single sprint and Illinois agility tests (p < 0.05). Thus 8-weeks performing the 11+ warm-up program can enhance jump height, agility and soccer skill while the HarmoKnee program generally only improves soccer skill in young professional male soccer players.
BACKGROUND: The isokinetic hamstrings to quadriceps (H:Q) dynamic control ratio (DCR) is frequently used to assess muscle imbalances and to screen for potential risks of knee injuries in sports. OBJECTIVE: To investigate the correlation between knee conventional ratio (CR) and DCR in elite soccer players and check for a possible relationship. A positive correlation would indicate that the CR could predict DCR. METHODS: One hundred and thirteen Brazilian elite soccer players (25.2 ± 5.3 yrs) performed maximal dominant and non-dominant knee concentric (CON) and eccentric (ECC) strength tests at 60 • /s on an isokinetic dynamometer in order to calculate CR and DCR. RESULTS: A significant positive correlation between ratios was found for the dominant and non-dominant knees (r = 0.54 and 0.62; p < 0.001 which translated into low R 2 values of 0.29 and 0.39, respectively. CONCLUSION: This suggests that the CR may not replace the DCR and is thus of a limited clinical value in assessing knee muscles imbalance. On the other hand, the paper presents for the first time a robust reference frame for the isokinetic strength and related ratios of the two major knee muscles in soccer players.