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ORIGINAL ARTICLE
Year : 2015  |  Volume : 15  |  Issue : 3  |  Page : 254-261

Reducing the risk of noncontact anterior cruciate ligament injuries and performance adaptations to "sportsmetric training" in elite female basketball players


Department of Sports Medicine and Physiotherapy, Guru Nanak Dev University, Amritsar, Punjab, India

Date of Web Publication2-Sep-2015

Correspondence Address:
Amrinder Singh
Faculty of Sports Medicine and Physiotherapy, Guru Nanak Dev University, Amritsar, Punjab
India
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DOI: 10.4103/1319-6308.164299

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  Abstract 

Context: Understanding the effect of "sportsmetric training (SMT) on reducing the risk of noncontact anterior cruciate ligament (ACL) injuries and performance adaptations in elite female basketball players." Aims: The purpose of this study was to determine if the sportsmetrics basketball training program would be effective in improving neuromuscular performance indices, thereby allowing recommendation for the program for both an injury prevention and enhancement of sport activity. Settings and Design: Present experimental study conducted at basketball court in Guru Nanak Dev University, Punjab (India). Subjects and Methods: Forty interuniversity female basketball elite players (mean age 20.0 ± 1.2 years; mean height, 163.4 ± 4.4; mean mass 52.1 ± 4.9 kg) volunteered and were randomly assigned into two groups. Both experimental group and control group were assessed for lower limb alignment on the video drop-jump test, vertical jump height assessed by kinematic measuring system and agility assessed by Illinois test. Control group had followed their routine training, and experimental group had performed sportsmetrics training for 6 weeks. After 6 weeks of training postmeasures were taken. Statistical Analysis Used: Significance was defined as P ≤ 0.05. Paired t-test was conducted for all the variables of within the groups. Unpaired t-test was run for comparison of all the parameters of between the SMT and control groups. Results: In the video drop-jump test, significant changes were found in the mean absolute knee separation distances on landing phases of jump in within training group and between the groups. There were also significant changes observe in vertical jump and Illinois agility test in within training group as well as between the groups. Conclusions: This program significantly improved lower limb alignment on a drop-jump test and thereby reducing the risk of noncontact ACL injury as well as improved performance indices and may be implemented preseason or off season.

  Abstract in Arabic 

الملخص:
السياق: فهم أثر التدريب sportsmetric على الحد من خطر الأمامي نونكونتاكت إصابات الرباط الصليبي والتكييف الأداء في النخبة لاعبي كرة السلة للإناث "
الأهداف: كان الهدف من هذه الدراسة هو تحديد ما إذا كان برنامج التدريب sportsmetrics كرة السلة ستكون فعالة في تحسين مؤشرات الأداء العصبية والعضلية، مما يسمح توصية للبرنامج لكلا من الوقاية من الإصابات وتعزيز النشاط الرياضي.
ضبط وتصميم: دراسة تجريبية الحالية التي أجريت في ملعب لكرة السلة في ناناك ديف جامعة، البنجاب (الهند).
الأساليب والمواد: 40 بين الجامعات لكرة السلة النسائية اعبي النخبة (متوسط العمر 20.0 ± 1.2 سنوات؛ يعني الطول، 163.4 ± 4.4، يعني كتلة 52.1 ± 4.9 كلغ) تطوعوا وتم توزيعهم عشوائيا إلى مجموعتين. تم تقييم كل من مجموعة مجموعة والسيطرة التجريبية لانخفاض محاذاة الطرف على الفيديو قطرة قفزة اختبار، ارتفاع القفز العمودي المقررة من قبل نظام القياس الحركية وسرعة المقررة من قبل إلينوي الاختبار. والمجموعة الضابطة جاءت تدريبهم الروتيني وكانت المجموعة التجريبية أداء التدريب sportsmetrics لمدة 6 أسابيع. بعد 6 أسابيع من تدابير ما بعد التدريب تم اتخاذها.
التحليل الإحصائي المستخدمة: تم تعريف أهمية كما P ≤ 0.05. وقد أجريت يقترن ر اختبار لجميع المتغيرات من داخل المجموعات. تم تشغيل المفردة ر الاختبار للمقارنة بين جميع المعلمات من بين SMT ومراقبة المجموعات.
النتائج: في الفيديو قطرة قفزة اختبار، تم العثور على تغييرات كبيرة في متوسط المسافات الفاصلة الركبة المطلقة على مراحل الهبوط من القفز في داخل مجموعة التدريب وبين الجماعات. كانت هناك أيضا تغييرات كبيرة نلاحظ في الوثب العمودي وإلينوي اختبار خفة الحركة في داخل مجموعة التدريب وكذلك بين المجموعات.
الاستنتاجات: هذا البرنامج تحسنت بشكل ملحوظ أقل محاذاة الطرف على اختبار الوثب drop- وهناك عن طريق الحد من مخاطر عدم الاتصال إصابة ACL فضلا عن تحسين مؤشرات الأداء ويمكن تنفيذ قبل بداية الموسم أو غير موسمها.

Keywords: Agility, anterior cruciate ligament, lower limb alignment, vertical jump, video drop-jump


How to cite this article:
Singh A, Darji MP, Shenoy S. Reducing the risk of noncontact anterior cruciate ligament injuries and performance adaptations to "sportsmetric training" in elite female basketball players. Saudi J Sports Med 2015;15:254-61

How to cite this URL:
Singh A, Darji MP, Shenoy S. Reducing the risk of noncontact anterior cruciate ligament injuries and performance adaptations to "sportsmetric training" in elite female basketball players. Saudi J Sports Med [serial online] 2015 [cited 2019 May 20];15:254-61. Available from: http://www.sjosm.org/text.asp?2015/15/3/254/164299


  Introduction Top


Basketball requires flexibility, agility, strength, and endurance. Lower limb is the most frequently injured in this game. [1] of which, 25% injuries occur on the knee [2] anterior cruciate ligament (ACL) is one of the most commonly injured ligaments in the knee. [3] A torn ACL usually occurs through a twisting force being applied to the knee while the foot is firmly planted on the ground or upon landing (valgus collapse with the knee close to full extension combined with external or internal rotation of the tibia) [4] called noncontact ACL injury or a result from a direct blow to the knee, usually the outside, as may occur during a tackle, known as direct ACL injury. [5] The rate for noncontact ACL injuries ranges from 70 to 84% of all ACL tears in both female and male athletes. Females injure their ACL 4 to 6 times more frequently than their male counterparts. [6] The factors affecting this predominance have been considered to be divided into hormonal (estrogen), anatomical (narrow intercondylar notch, wider pelvis and greater Q angle) environmental (playing style), and neuromuscular (dominance of quadriceps muscle recruitment for dynamic stability). [3]

The reason for understanding factors leading to the predominance of ACL injury in female athletes is for administering prevention strategies. While there have been efforts focused on ACL injury treatment strategies, it is well-established that surgical reconstruction does not reduce the increased risk for developing posttraumatic knee complication. [7] Furthermore, apart from the short- and long-term physical impairments, ACL injury causes personal and professional impairment for athletes, with high costs in rehabilitation for both athletes and sports institutions. [8] Thus, the prevention of noncontact ACL injuries has become a major milestone in sports traumatology.

Many basketball training programs have been developed to improve player fitness and skill and hypothetically prevent injuries. [2],[9],[10],[11] Investigations vary considerably in the selection of participants, duration of training, exercises and drills performed, and outcome measures. Only one study that assessed performance indices in female basketball players using the sportsmetrics training program. [12] A small group of female collegiate basketball players obtained significant improvements in hamstring peak torque (P = 0.008), which were not found in the control group of players. Development of hamstrings strength is believed to be one important factor in preventing knee ligament injuries in female athletes. [5],[13],[14]

Sportsmetrics neuromuscular training for female athletes involved in a variety of sports 15 years ago. [15] and noted occasional problems with player compliance with the program. The training consisted of a dynamic warm-up, jump training, strength training, and flexibility. Over time, players and coaches requested that the program be modified to include additional sport-specific exercises and drills designed to improve speed, agility, strength (upper extremity, lower extremity, and core), and aerobic conditioning. In addition, other investigators noted that improved compliance with injury prevention training programs would most likely occur if the programs target performance enhancement and neuromuscular retraining. [5],[16] Hence, to improve player's compliance and participation for competitive events sports specific programs developed by Barber-Westin and Noyes; [17] soccer Barber et al., [18] lacrosse, volleyball, and tennis Barber-Westin et al. [18] These training programs consist of the essential sportsmetrics neuromuscular retraining principles previously proven to reduce the rate of noncontact ACL injuries in female athletes, along with other sports-specific exercises and drills.

In the study, Barber-Westin et al. [19] hypothesized that during a video drop-jump, females have decreased knee separation (SEP) distances upon landing and acceleration; male athletes have neutrally aligned lower limb positions upon landing and acceleration; and a 6-week neuromuscular training program will significantly increase knee SEP distance in female athletes.

The main outcome variables were knee SEP distance, ankle SEP distance and how the training regimen changes knee and ankle SEP distances in females only. These distances were measured off of a video screen. Both females and males have valgus alignment and that the females had improved knee SEP distance after training. [20]

There were importance analysis of endurance, muscular strength and power, sprint speed, agility, and jumping ability in basketball. [21]


  Subjects and Methods Top


Experimental approach to the problem

This study was undertaken to determine if a sportsmetric training (SMT) program could improve neuromuscular performance indices in female Elite basketball players. A program was devised, which used the dynamic warm-up, jump training, strength training, and flexibility components from a previously published ACL injury prevention program, [17] along with new exercises and drills to improve speed, agility, overall strength. A battery of tests was conducted to determine the effectiveness of this training program in improving lower limb alignment on a drop-jump test, vertical jump height, and agility performance.

Forty interuniversity female basketball elite players (mean age 20.0 ± 1.2 years; mean height, 163.4 ± 4.4; mean mass 52.1 ± 4.9 kg) were randomly assigned into two groups: Control (n = 20) and SMT (n = 20). All testing and training procedures, benefits, and potential risks of the study were explained to the participants before signing the informed consent form and starting the test. "This study was approved by the Institutional Ethics Committee of Faculty of Sports Medicine and Physiotherapy, Guru Nanak Dev University, Amritsar. Each participant voluntarily provided written informed consent before participating."

The study inclusion criteria included the following: Participants agreed with the purpose of this study, participants had no existing musculoskeletal problems such as lower limb fracture and sprain/strain, subjects had no recent injury to lower limb, participants had no existing neurologic problems and participants had no existing respiratory or cardiovascular system problems during running. None of the participants had participated in a formal neuromuscular or resistance training program, but all had at least one season of experience.

Data collection

All qualified participants reported to the laboratory and selected outdoor tracks for testing on two occasions: (a) Pretraining and (b) 6 weeks posttraining for lower limb alignment on drop-jump test, vertical jump test and agility assessed by Illinois test. Control group had followed their routine training, and experimental group had performed sportsmetrics training for 6 weeks.

Procedures

Video drop-jump test

Participants performed a drop-jump sequence by first jumping off a box 30.48 cm in height, landing, and immediately performing a maximum countermovement vertical jump. No specific instructions were provided regarding how to land or jump; participants were only instructed to land straight in front of the box. This sequence was repeated 3 times. Three images were captured that represented the preland, land, and take-off phases. The absolute centimeters of SEP distance between the right and left hips, knees, and ankles were measured by sport motion analysis system 101. The absolute centimeters of SEP distance between the right and the left hip and normalized SEP distances for the knees and ankles, standardized according to the hip SEP distance, are analyzed. Normalized knee SEP distance is calculated as knee SEP distance divided by hip SEP distance, and normalized ankle SEP distance is calculated as ankle SEP distance divided by hip SEP distance. The reliability of the drop-jump test has been reported previously. [22]

Vertical jump test

Double leg vertical jump power was measured with a counter movement vertical jump using contact timing mats interfaced to a computer (kinematic measurement system). Each participant was made to jump for three trials, and the highest jump was noted. Participants were instructed to keep their arms on their hips during the vertical jumps to eliminate upper body momentum.

Illinois agility test

The length of the course is 10 m, and the width (distance between the start and finish points) is 5 m. Four cones are used to mark the start, finish, and the two turning points. Another four cones are placed down the center an equal distance apart. Each cone in the center is spaced 3.3 m apart. Participants should lie on their front (head to the start line) and hands by their shoulders. On the "go" command, the stopwatch is started, and the athlete gets up as quickly as possible and runs around the course in the direction indicated, without knocking the cones over, to the finish line, at which the timing is stopped. [23]

Protocol

Experimental group participated in the program 3 sessions/week on alternate days for 6 weeks for SMT program [Table 1]. The sessions lasted approximately 90-120 min and consisted of a dynamic warm-up, jump training, strength training, speed, and agility drills specific for basketball and flexibility. [24]
Table 1: Protocol of SMT program

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Data analysis

Significance was defined as P ≤ 0.05. Paired t-test was conducted for all the variables of within the groups. Unpaired t-test was run for comparison of all the parameters of between the SMT and control groups. The absolute centimeters of SEP distance between the right and the left hip and normalized SEP distances for the knees and ankles, standardized according to the hip SEP distance, are analyzed. Normalized knee SEP distance is calculated as knee SEP distance divided by hip SEP distance, and normalized ankle SEP distance is calculated as ankle SEP distance divided by hip SEP distance.


  Results Top


In video drop-jump test, statically significant increases were found in knee SEP distance in within the SMT group in landing phase (P < 0.001) [Table 2] as well as between the control and the SMT groups in landing phase (P < 0.0001) [Table 2] and [Graph 1] which reflected improvement in lower limb alignment on a drop-jump from a valgus position to a more neutral position.
Table 2: Summary of video drop-jump test: Landing phase

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Basketball player demonstrated a 40.16% normalized knee SEP distance and 48.92% normalized ankle SEP distance, with a notable valgus lower limb alignment. Bottom, after training, they had a markedly improved 59.2% normalized knee SEP distance and a more neutral lower limb alignment with 56.37% normalized ankle SEP distance [Figure 1] and [Graph 2].
Figure 1: Summary of normalized knee separation (SEP) and normalized ankle SEP before and after 6 weeks: The absolute centimeters of distance between the hips, knees, and ankles are shown on the left of the stick figures, whereas the normalized knee and ankle SEP distances are shown on the right. Top, before training, this basketball player demonstrated a 40.16% normalized knee SEP distance and 48.92% normalized ankle SEP distance, with a notable valgus lower limb alignment. Bottom, after training, they had a markedly improved 59.2% normalized knee SEP distance and a more neutral lower limb alignment with 56.37% normalized ankle SEP distance

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There were also significant improvement found in vertical jump height within the SMT group (P < 0.0001) as well between the control and the SMT groups (P < 0.0001) [Table 3] and [Graph 3].
Table 3: Summary of vertical jump height parameter

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Illinois agility test also showed significant improvement within the SMT group (P < 0.0001) as well between the control and the SMT groups (P < 0.0001) [Table 4] and [Graph 4].
Table 4: Summary of Illinois agility parameter

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  Discussion Top


The main findings of this study were a significant improvement in lower limb alignment on all phases from drop-jump. Improvement in lower limb alignment on a drop-jump from a valgus position to a more neutral position is believed to be beneficial in preventing noncontact ACL injuries. [25],[26]

Statistically significant improvements were found in absolute knee SEP distance for landing phase of jump-land sequences [Table 1] and [Figure 1]. Decreased adduction moments may lessen the risk of lift-off the medial or lateral femoral condyle, improve tibiofemoral contact stabilizing forcess [27] and reduces the risk of a knee ligament injury.

A laboratory study was conducted by Hewett et al. [28] in 11 high school volleyball players to determine the effect of SMT on land mechanics and lower extremity strength showed decreased peak landing forces from volleyball block jump by 22% (P = 0.006) and decreased knee abduction and adduction moment by 50%.

In present study, video drop-jump test also showed significant improvement in the normalized knee SEP distances by 59.2% and in the normalized ankle SEP distances by 56.37% as compared to prior 6 weeks SMT, similarly in one investigation, 16 competitive, experienced female high school volleyball players underwent the video drop-jump test and then completed the SMT program. The athletes repeated the drop-jump test immediately upon completion of 6 weeks of training and then 3 and 12 months later. Significant improvements were found in the mean normalized knee SEP distance between the pre- and post-trained values of all test sessions (P < 0.01) which retained up to 1-year after sportsmetrics training in a group. [18]

This lower limb alignment is believed to be a potential risk factor for a future noncontact ACL injury and the International Olympic Committee recommended use of the drop-jump test to identify athletes at-risk for a noncontact ACL injury. [26] Subjective interpretation of knee control on landing during this test provided a useful screening tool for identifying athletes with poor lower limb mechanics. [29]

Studies that analyzed ACL injuries using video analysis of the actual event commonly described a valgus knee position that was present either milliseconds before, after, or at the time of the ligament rupture. [18],[27],[28] The drop-jump video test provides a general indicator of an athletes' lower limb axial alignment in the coronal plane because it shows the position of the hips, knees, and ankles in a single plane during one task. It is important to note that many noncontact ACL injuries usually occur in side-to-side, cutting, or multiple complex motions in more than one plane.

In this study, improvement found in vertical jump height (P < 0.0001). Advanced plyometric training does carry the risk of injury or the development of an overuse syndrome. We believe that athletes must first be taught proper jump and landing techniques through this SMT program described in this investigation before performing advanced plyometrics. In addition, supervision is required to ensure the athlete performs the exercises safely and correctly. Chappell and Limpisvasti [9] reported significant increases in vertical jump height in a study consisting of 12 collegiate female basketball players and 18 collegiate female soccer players. The athletes participated in a 15-min warm-up program that included core strength, single-leg passing, and 3 jumps before each practice during their season. Vertical jump height increased 7%, from 45.13 to 48.9 cm (P, 0.001) after training. Summarized data from 56 studies that assessed the effects of plyometric training on improving vertical jump height and concluded that a combination of squat, countermovement, and depth jumps was significantly more effective than the use of a single plyometric exercise (P, 0.05). [30]

These are key coordinative components of athleticism. Agility training often closely resembles the actual sporting activity and may, therefore, be the most effective way to address neuromuscular demands required to perform sport specific skills. The primary effect of agility training is the improvement of overall body control and awareness. This aids in heightening overall athleticism, which improves proficiency at nearly every athletic activity. In this study, there were also significant increases found in agility performance in this study which will reflect adaptation in performance indices of the athlete.


  Conclusions Top


This program significantly improved lower limb alignment on a drop-jump test and thereby reducing the risk of noncontact ACL injury as well as improved performance indices and may be implemented preseason or off season. The findings of this study indicate the effectiveness of a new basketball training program in female athletes. This program can be efficient for 17-year to 25-year range of age groups but may be or may not be employed in other age groups which will require further future research study to understand. The program combines components from a previously published ACL injury prevention program for jump and strength training with other exercises and drills to improve speed, agility, overall strength. We recommend that coaches and trainers who wish to implement this program conduct the tests that were done in this study to determine the overall effectiveness of the program. Athletes who fail to improve should be encouraged to continue neuromuscular SMT.


  Acknowledgments Top


The authors are thankful to their participants. The permission was taken from Ethical Committee of Guru Nanak Dev University, Amritsar, Punjab (India).

 
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    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]


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