Biomechanical analysis of the muscular power of martial arts athletes

Correlation analysis between biomechanical characteristics of lower extremities during front roundhouse kick in Taekwondo and effective scores of electronic protectors

Objective: The purpose of this study is to analyze the inherent relationship between the score values and the biomechanical characteristics of the forward kicking motion, we aim to identify the fundamental variables influencing the score values of the forward kicking motion and establish the key biomechanical factors that effectively trigger scoring in the forward kicking motion. Methods: The DaeDo electronic scoring system was used with the Vicon optical motion capture system and the Kistler 3D force platform to obtain kinematic and kinetic variables of the front roundhouse kick motion. Linear bivariate correlation analysis and principal component analysis were used to analyze the associations between kinematic, kinetic variables, and scoring values, and summarize key biomechanical factors for effectively scoring. Results: The peak ankle plantar flexion angle and knee extension torque of the kicking leg showed a significant negative correlation with scoring values (r < 0, p < 0.05), while other variables showed no statistical significance. The peak knee flexion angle and hip extension angular velocity of the supporting leg showed a significant positive correlation with scoring values (r > 0, p < 0.01), while the peak ankle plantar flexion torque showed a significant negative correlation with scoring values (r < 0, p < 0.05), and other variables showed no statistically significant correlation. The absolute values of eigenvectors of the first and second principal components, which included hip angular velocity, ankle angle, knee torque, and hip torque, were relatively large, indicating their strong influence on effective scoring triggering. Conclusion: Maintaining ankle dorsiflexion and a larger knee flexion angle in the kicking leg is favorable for triggering scoring. Higher knee flexion angle and hip extension angular velocity in the supporting leg are also advantageous for triggering scoring. "Body posture" and "Strength" are key factors that effectively trigger scoring.

Correlation analysis between biomechanical characteristics of taekwondo double roundhouse kick and effective scoring of electronic body protector

Objective: To explore the inherent relationship between lower limb biomechanical indicators and effective scoring values of double roundhouse kick (DRK) by taekwondo athletes, and to find key biomechanical factors that trigger effective scoring. Methods: Using the DAEDO Protector and Scoring System (PSS) in conjunction with the Vicon optical motion capture system and Kistler 3D force plate, kinematic and dynamic indicators of the front kicking motion were obtained from 12 professional taekwondo athletes (18.00 ± 2.20 years, 182.15 ± 8.62 cm and 70.00 ± 14.82 kg). The correlation between kinematics, dynamics, and scoring values was initially analyzed using bivariate linear correlation. Subsequently, based on the results of the linear correlation analysis, a stepwise regression analysis was performed to establish a stepwise regression equation. Results: The results reveal that during the First Hit, there is a significant positive correlation (r > 0, p < 0.05) between peak hip flexion angular velocity of the dominant leg, knee abduction angle, and peak foot horizontal plane linear velocity of the non-dominant leg with effective score. On the other hand, peak ankle flexion angular velocity of the non-dominant leg, peak foot sagittal plane linear velocity, peak hip abduction angle, and peak hip flexion angle of the dominant leg exhibit a significant negative correlation (r < 0, p < 0.05) with effective score. These correlations hold statistical significance (DW> 1.023). During the Second Hit, there is a significant positive correlation (r > 0, p < 0.05) between peak ankle internal rotation angular velocity of the dominant leg, foot coronal plane linear velocity, hip adduction angular velocity, and peak ankle internal rotation moment of the non-dominant leg with effective score. Conversely, peak hip flexion angle of the dominant leg shows a significant negative correlation (r < 0, p < 0.05) with effective score. All these variables have a statistically significant impact on effective score (DW > 1.023). Conclusion: Explosive power, body posture, adequate terminal velocity, and body rotation have an association with effective scoring of the electronic protector. The peak angular velocity of the ankle joint of the dominant leg and the peak linear velocity of the foot horizontal plane of the non-dominant leg significantly contribute to the effectiveness score of the electronic protector.

Effects of different drop height training on lower limb explosive and change of direction performance in collegiate Sanda athletes

The purpose of the present study was to examine the effects of 6 weeks of 40-, 60-, or 80-cm drop jump (DJ) training on lower limb explosive and change of direction (CoD) performance in collegiate Sanda athletes. Repeated-measure ANOVA revealed that there was a significant group × time interaction for standing long jump test (p = 0.006), counter movement jump test (p = 0.026), Illinois agility test (p = 0.003), square test (p = 0.018), Nebraska test (p = 0.027), t test (p = 0.032), and hexagon test (p = 0.012) due to the best performance observed at post-test compared with pre-test for DJ60 (effect size = 0.89-2.89), and the improvement was higher than that of the other groups. These findings suggest that 6 weeks of DJ training could improve the lower limb explosive and CoD performance in collegiate Sanda athletes and that 60 cm may be the optimal drop height.

Comparison of Selected Characteristics of Slovak and Polish Representatives in Kickboxing

BACKGROUND

Previous kickboxing studies conducted over the last three decades have focused on improving performance through physical fitness characteristics; however, most of the research focused on men. The objective of this study is to assess the level of physical fitness of Slovak and Polish female kickboxers in the highest sport level as well as to compare the differences between them.

METHODS

The study included 20 female kickboxers on the highest level of sport performance, 10 from Slovakia (body mass-53.59; height-166.45) and 10 from Poland (body mass-60.35; height -169.95), from senior categories, with a mean age of 23 ± 2. The selection criteria included training experience and sports level. The level of physical fitness was evaluated by the following tests: Cooper's test, 50 m sprint, sit-ups, flexed arm hang and standing long jump. Technical and tactical indicators were used to assess the sports skill level during the competition.

RESULTS

The test results of both groups are very comparable based on the evaluated data of Kruskal-Wallis ANOVA. The attack activity index together with sit-ups demonstrated statistically significant differences (p < 0.05) between Slovak and Polish kickboxers. A strong positive correlation was proven between technical and tactical indicators and physical fitness tests in the results of both groups.

CONCLUSIONS

There exists a positive correlation between the technical and tactical indicators of kickboxers and the explosive strength of lower limbs, strength endurance, abdominal muscle strength, speed and aerobic endurance. Differences between Slovak and Polish kickboxers have been shown in the attack activity index and in the level of strength endurance. The level of speed and explosive power of the lower limbs was comparable in both groups of kickboxers.

The Effectiveness of a Group Kickboxing Training Program on Sarcopenia and Osteoporosis Parameters in Community-Dwelling Adults Aged 50-85 Years

Background

Sarcopenia and osteoporosis are important health issues faced by older people. These are often associated with each other and share common risk factors and pathologic mechanisms. In the recently revised consensus of the European Working Group on Sarcopenia in Older People, low muscle strength has been defined as the first characteristic of sarcopenia rather than a loss in muscle mass, and walking speed has been stated as an indicator of the severity of sarcopenia. It is believed that these markers of muscle function can be potentially reversed via exercise-based interventions. The purpose of this study was to evaluate the effects of kickboxing exercise training on the parameters of sarcopenia and osteoporosis in community-dwelling adults.

Methods

In total, one hundred eligible subjects were randomized into an intervention group (n = 50) with 76% women and control group (n = 50) with 86% women. Both the intervention and control groups were provided with classroom lectures and personal consultations pertaining to sarcopenia and osteoporosis, whereas a 12-week kickboxing exercise training was arranged only for the intervention group. All anthropometric, physical performance, body composition, and bone mineral density measurements along with participant completed questionnaires were conducted before and after the training period.

Results

After 12 weeks, 41 participants in the intervention group and 34 participants in the control group completed the final assessments. There was no difference between the intervention and control groups in terms of basic demographic data. The BMI (+1.14%) of the control group increased significantly during the study period. The waist circumference (−6.54%), waist-to-height ratio (−6.57%), waist–to–hip ratio (−4.36%), total body fat (−1.09%), and visceral fat area (−4.6%) decreased significantly in the intervention group. Handgrip strength (+5.46%) and gait speed (+5.71%) improved significantly in the intervention group. The lean body mass increased by 0.35% in the intervention group and by 0.9% in the control group. The femoral neck bone mineral density (−1.45%) and T score (−3.72%) of the control group decreased significantly. The intervention group had more improvement in the status of sarcopenia (OR 1.91) and osteoporosis over the control group. Finally, the intervention group had less deterioration in the status of sarcopenia (OR 0.2) and osteoporosis (OR 0.86) compared with the control group.

Conclusion

Our study demonstrated that a 12-week kickboxing exercise training program is effective for improving sarcopenic parameters of muscle strength and function, but not muscle mass in adults, aged 50–85 years. Furthermore, markers of osteoporosis also showed improvement. These findings suggest that a 12-week kickboxing program is effective for muscle and bone health among community-dwelling older individuals.

The control of respiratory pressures and neuromuscular activation to increase force production in trained martial arts practitioners

PURPOSE

The mechanisms that explain the ability of trained martial arts practitioners to produce and resist greater forces than untrained individuals to aid combat performance are not fully understood. We investigated whether the greater ability of trained martial arts practitioners to produce and resist forces was associated with an enhanced control of respiratory pressures and neuromuscular activation of the respiratory, abdominal, and pelvic floor musculature.

METHODS

Nine trained martial arts practitioners and nine untrained controls were instrumented with skin-surface electromyography (EMG) on the sternocleidomastoid, rectus abdominis, and the group formed by the transverse abdominal and internal oblique muscles (EMG_tra/io). A multipair oesophageal EMG electrode catheter measured gastric (P_g), transdiaphragmatic (P_di), and oesophageal (P_e) pressures and EMG of the crural diaphragm (EMG_di). Participants performed Standing Isometric Unilateral Chest Press (1) and Standing Posture Control (2) tasks.

RESULTS

The trained group produced higher forces normalised to body mass^2/3 (0.033 ± 0.01 vs. 0.025 ± 0.007 N/kg^2/3 mean force in Task 1), lower P_e, and higher P_di in both tasks. Additionally, they produced higher P_g (73 ± 42 vs. 49 ± 19 cmH₂O mean P_g) and EMG_tra/io in Task 1 and higher EMG_di in Task 2. The onset of P_g with respect to the onset of force production was earlier, and the relative contributions of P_g/P_e and P_di/P_e were higher in the trained group in both tasks.

CONCLUSION

Our findings demonstrate that trained martial arts practitioners utilised a greater contribution of abdominal and diaphragm musculature to chest wall recruitment and higher P_di to produce and resist higher forces.

Effects of Ving Tsun sticking-hand training on upper-limb sensorimotor performance in community-dwelling middle-aged and older adults: A randomized controlled trial

Objective

To evaluate the effects of Ving Tsun (VT) sticking-hand training on upper-limb joint position sense and muscular performance in community-dwelling middle-aged and older adults.

Methods

Thirty-three adults were randomly allocated to either a VT group or a control group. The VT group received VT sticking-hand training twice per week for 3 months. Measurements were taken before and after the intervention period. The primary outcome was elbow-joint repositioning error, which was measured by an elbow-joint passive positioning and active repositioning test using a universal goniometer. Secondary outcomes were upper-limb muscles’ peak force and time taken to reach peak force as measured by a hand-held dynamometer.

Results

No significant time, group or time-by-group interaction effects were found for elbow-joint repositioning error or upper-limb muscle peak force outcomes. Shoulder flexor time to peak force decreased by 33.8% from pre-test to post-test in the VT group (P = 0.007). Shoulder abductor, internal and external rotator, and elbow extensor times to peak force decreased by 30.0%–35.9% in the VT group (P < 0.05) and by 30.4%–37.1% in the control group (P < 0.05).

Conclusions

VT sticking-hand training does not improve elbow-joint position sense or the maximum strength of upper-limb muscles in middle-aged and older adults. However, VT can improve shoulder flexor muscles’ time to reach peak force in these populations. VT had no obvious effect on the time required to reach peak force in other shoulder muscles and elbow extensors.

Anthropometric characteristics and physical performance of taekwondo athletes

Abstract The purpose of this investigation was to measure anthropometric and physical performance variables of TKD athletes from the city of Pelotas - RS. Forty-five athletes aged 16.4 ± 5.2 years and time of practice of 3.25 ± 3.6 years were evaluated. Athletes performed anthropometric evaluation and physical, general and specific performance tests. In the sum of seven skin folds, men presented lower values ??(106.1 ± 49.5 mm versus 143.4 ± 43.2 mm, p <0.002). Male seniors presented better performance in the vertical jump compared to beginners (42.3 ± 8.5cm versus 24.8 ± 10.1cm, p <0.03) and to women (22.1 ± 4.3cm, p <0.03). Graduated individuals perform higher number of arm pushups than beginners and women and more repetitions in the abdominal test. Male junior and senior athletes had higher isometric handgrip strength than females (48.3 ± 3.9 kgf and 38.1 ± 12.6 kgf versus 29 ± 5.6 kgf, p <0.001). Men covered longer distance in the yo-yo test than women (606.6 ± 233.8m versus 200 ± 113.1m, p <0.001). In the Wingate test, men produced greater peak and average relative power. No differences in flexibility were observed. In the single kick test, seniors kicked faster than less experienced athletes (200.6 ± 12.3m / s versus 258 ± 5.6m / s, p <0.001) and performed greater number of kicks in the 21s, 6 ± 2.1 reps versus 15.5 ± 0.7 reps, p <0.001). It was concluded that there are differences between male and female TKD athletes regarding anthropometric and motor characteristics, and that more experienced athletes exhibit greater general and specific physical fitness.

Dynamic Analysis of Vibration, Muscle Firing, and Force as a Novel Model for Non-Invasive Assessment of Joint Disruption in the knee: A Multiple Case Report

We present a new method for understanding knee pathology through non-invasive techniques. The combination of electromyography (EMG), vibroarthrographic (VAG), and force analysis in proposed to examine the force transfer between unhealthy and healthy knees. A multiple case report is presented to demonstrate the technique and its potential application for future study. The comparison of four individuals’ knee characteristics will be explained using this innovative methodology.

The improvement of suspension training for trunk muscle power in Sanda athletes

The aim of this study was to investigate whether both suspension training (ST) and traditional training (TT) can improve Sanda athlete's strength quality of trunk muscles and to explore the effect of suspension training on Sanda athletes' trunk muscle power production. Twelve elite Sanda athletes from the Competitive Sports School of Shanghai University of Sport were randomly assigned to experimental group (EG) and control group (CG). EG and CG were regularly trained with suspension training and traditional strength training for 40 minutes three times per week. The total duration of training was 10 weeks. The measurements including peak torque (PT), PT/body weight (BW), and rate of force development (RFD) were used to assess trunk muscles strength. The results showed that there were significant differences between the two groups' performance when it was tested at the higher velocity of dynamometer (test of muscle power), but less significant differences when the two groups performance was tested at the lower velocity of dynamometer (test of maximum strength). The conclusion of this study is that compared with traditional training methods, suspension training can improve back and trunk flexion muscles strength more effectively. In particular, suspension training can improve the explosive power of trunk extension and flexion muscles.

Kickboxing review: anthropometric, psychophysiological and activity profiles and injury epidemiology

Kickboxing is one of the modern combat sports. The psychophysiological demands of a kickboxing competition require athletes to achieve high thresholds of several aspects of physical fitness. The aim of the current review is to critically analyse and appraise the kickboxer’s anthropometric, physiological, physical and psychological attributes with the activity profile and injury epidemiology in order to provide practical recommendations for training as well as new areas of scientific research. The available information shows that both amateur and elite-level male kickboxers are characterized by a higher proportion of mesomorphy with a well-developed muscle mass and low body fat percentage. While there is some variation in the maximum oxygen uptake of kickboxers, moderate to high cardio-respiratory levels are reported for these athletes. Regardless of kickboxers’ level, a high peak and mean anaerobic power output were reported. High-level kickboxing performance also requires well-developed muscle power in both the upper and lower limbs. Psychological factors contribute to success that requires high levels of self-confidence, motivation, dispositional hope and optimism, mental toughness/resiliency, and adaptive perfectionism. Psychological attributes also distinguished successful from less successful kickboxers. The activity-to-rest ratio was higher in elite (1:1) than both amateur and national-level (from 1:2 to 1:5) kickboxers, with no significant differences between rounds (round 1=1:4, and rounds 2 and 3=1:5) as well as between winners and losers in amateur and national-level simulated combats. These particular psychophysiological characteristics and performance aspects of kickboxers influence performance and could serve as guidance for training. Finally, kickboxing is characterized by chronic repetitive head trauma, which causes hypopituitarism due to traumatic brain injury (TBI). Future investigations into the physical, physiological and psychological characteristics related to age, gender and competitive levels of kickboxers are required to enrich the current knowledge and to help create the most suitable training programme.

Musculoskeletal profile of middle-aged Ving Tsun Chinese martial art practitioners: A cross-sectional study

This cross-sectional exploratory study aimed to quantify and compare the axial and appendicular bone mineral density (BMD), muscle mass, and muscle strength of middle-aged practitioners of Ving Tsun (VT; a hard-style Chinese martial art) with those of nonpractitioners.Eighteen VT practitioners (mean age ± standard deviation = 51.8 ± 17.7 years; 12 men and six women) and 36 active controls (mean age ± standard deviation = 58.7 ± 11.0 years; 18 men and 18 women) participated in the study. All participants underwent a 1-day battery of musculoskeletal examinations. The BMD of the total radius, total hip, femoral neck, and lumbar spine was measured using dual-energy X-ray absorptiometry, as was the lean mass of the arm, leg, and trunk. Muscle strength of the upper and lower limbs was assessed using a Jamar dynamometer and an isokinetic dynamometer at 60°/second, respectively.VT-trained participants had a 11.5% higher total radius BMD (P = 0.023), a 17.8% higher leg lean mass (P = 0.014), a 56.4% higher isokinetic body weight-adjusted peak torque of the knee extensors (P < 0.001), a 60.8% higher isokinetic body weight-adjusted peak torque of knee flexors (P < 0.001), and a 31.4% shorter time to reach peak torque in the knee flexors (P = 0.001) than the active controls. No significant differences were found in any of the other musculoskeletal outcomes between the 2 groups (P > 0.05).Middle-aged VT practitioners displayed a higher total radius BMD and leg lean mass and better knee extensor and flexor muscular performances than their healthy active counterparts. Healthcare professionals may consider using this alternative method of training to improve the musculoskeletal health of middle-aged adults.

Determination of Aerobic Power Through a Specific Test for Taekwondo - A Predictive Equation Model

Our aim was to verify the concurrent validity of a maximal taekwondo specific test (TST) to predict VO2max through an explanatory model. Seventeen elite male taekwondo athletes (age: 17.59 ± 4.34 years; body height: 1.72 ± 6.5 m; body mass: 61.3 ± 8.7 kg) performed two graded maximal exercise tests on different days: a 20 m multistage shuttle run test (SRT) and an incremental TST. We recorded test time, VO2max, ventilation, a heart rate and time to exhaustion. Significant differences were found between observed and estimated VO2max values [F (2, 16) = 5.77, p < 0.01]; post-hoc subgroup analysis revealed the existence of significant differences (p = 0.04) between the estimated VO2max value in the SRT and the observed value recorded in the TST (58.4 ± 6.4 ml/kg/min and 52.6 ± 5.2 ml/kg/min, respectively). Our analysis also revealed a moderate correlation between both testing protocols regarding VO2max (r = 0.70; p = 0.005), test time (r = 0.77; p = 0.02) and ventilation (r = 0.69; p = 0.03). There was no proportional bias in the mean difference (t = -1.04; p = 0.313), and there was a level of agreement between both tests. An equation/model was used to estimate VO2max during the TST based on the mean heart rate, test time, body height and mass, which explained 74.3% of the observed VO2max variability. A moderate correlation was found between the observed and predicted VO2max values in the taekwondo TST (r = 0.74, p = 0.001). Our results suggest that an incremental specific test estimates VO2max of elite taekwondo athletes with acceptable concurrent validity.

The effect of core training on distal limb performance during ballistic strike manoeuvres

Ballistic limb motion is enabled by proximal "core" stiffness. However, controversy exists regarding the best method of training this characteristic. This study sought to determine the most effective core training method to enhance distal limb athleticism. A total of 12 participants (24 ± 3 years, 1.8 ± 0.05 m, 76.8 ± 9.7 kg) consisting of Muay Thai athletes performed a core training protocol (Isometric vs. Dynamic, with Control) for 6 weeks, using a repeated measures design to assess performance (peak strike velocity, peak impact force, muscular activation) in various strikes. Isometric training increased impact force in Jab (554.4 ± 70.1 N), Cross (1895.2 ± 203.1 N), Combo (616.8 ± 54.9 N), and Knee (1240.0 ± 89.1 N) trials (P < 0.05). Dynamic training increased strike velocity in Jab (1.3 ± 0.2 m · s^-1), Cross (5.5 ± 0.9 m · s^-1), Combo (0.7 ± 0.1, 2.8 ± 0.3 m · s^-1), and Knee (3.2 ± 0.3 m · s^-1) trials (P < 0.05). Isometric training increased Combo impact force 935.1 ± 100.3 N greater than Dynamic and 931.6 ± 108.5 N more than Control (P < 0.05). Dynamic training increased Jab strike velocity 1.3 ± 0.1 m · s^-1 greater than Isometric and 0.8 ± 0.1 m · s^-1 more than Control (P < 0.05). It appears that both static and dynamic approaches to core training are needed to enhance both velocity and force in distal limbs.

A follow-up study on the physique, body composition, physical fitness, and isokinetic strength of female collegiate Taekwondo athletes

The purpose of the study was to analyze changes in physique, body composition, physical fitness, and isokinetic strength in female collegiate taekwondo athletes. The study included 14 subjects, of whom 8 were followed up throughout the study. Anthropometric characteristics included body weight, height, sitting height, circumferences, and bone width. Physical fitness parameters included flexibility, agility, muscle strength, muscular endurance, power, speed, and cardiorespiratory endurance. Peak torque, mean power, and H/Q ratio were analyzed by using Cybex 770. All data were analyzed by using the SAS statistical program. Paired t test was performed, with 0.05 as the significance level. The results indicated significant changes in body weight, and upper arm and flexed upper arm circumferences during the experimental period. Test scores for plate tapping, and sit and reach significantly increased, but that for power decreased. In addition, the peak power of right flexion at 180°/sec was significantly increased, as well as the mean power of right and left flexion, and the H/Q ratio at 180°/sec.

Time-motion analysis of elite male kickboxing competition

The objective of the study was to analyze the time structure of high-level kickboxing matches. A total of 45 combats from 2 male World Championships were monitored using a time-motion analysis system. The combat time structure (i.e., high-intensity activity [HIA], low-intensity activity [LIA], and referee breaks or pauses) during competition and weight divisions was determined and compared. Results indicated that the time structures were HIA: 2.2 ± 1.2 seconds; LIA: 2.3 ± 0.8 seconds; pauses: 5.4 ± 4.3 seconds; and 3.4 ± 1.2 seconds between 2 subsequent HIA. The fighting to nonfighting ratio was found to be 1:1. Moreover, the number of HIA and LIA and the time of LIA decreased in latter rounds (e.g., the average number of HIA was 27.1 ± 7.1, 25.1 ± 6.6, and 24.9 ± 6.1, respectively, for rounds 1, 2, and 3), meanwhile the time and number of pauses increased (e.g., the average pause times were 12.8 ± 11.4, 22.3 ± 22.6, and 24.6 ± 23.3 seconds, respectively, for rounds 1, 2, and 3). The activity times did not differ among weight categories. The present results confirm the intermittent nature of kickboxing competition and provide coaches with more information on how to structure training sessions to mimic the physical demands in competition.

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.