N F N Bittencourt

Normative values of dynamic knee valgus during single leg squat in basketball and volleyball athletes

Background Volleyball and basketball are among the sports with a higher incidence of knee injuries. The inability to maintain a proper alignment of the lower limbs during functional activities could create a knee valgus which predisposes to injury. Thus, the quantification of knee valgus is necessary to guide prevention and clinical interventions. Objective To establish normative values for dynamic knee valgus during the single leg squat (SLS) in volleyball and basketball athletes. Design Observational cross-sectional. Setting Minas Tênis Club, Brazil, youth sports. Participants 151 athletes (108 male and 43 female) were assessed during national championship preseason. All participants were healthy, with no current pain of lower limb injury and no history of previous lower extremity surgery. The mean age, weight and height were 14.21+2.09; 62.75+14.20 and 173.89+13.42, respectively. Assessment of risk factors Gender, age and sport. Main outcome measurements Knee valgus was measured as frontal plane projection angle of the knee (FPPAK) during SLS up to 60° of knee flexion. The mean of three repetitions of SLS from each limb was used for analysis, using SIMI Motion Twinner software. The FPPAK was defined as the connections between ASIS, midpoint of femoral epicondyles and anterior midpoint of the malleolis. Results The mean FPPAK during SLS for right leg was 7.08+4.0 and 8.68+4.2 for left leg. There were no differences between ages and genders. There were significant differences between sides in both modalities (p<0.000).The basketball athletes had lower FPPAK on the left leg when compared with athletes from volleyball (p<0.000). Conclusion All athletes showed an inability to maintain proper alignment during dynamic squat. The differences found between modalities may be linked to the specific technique of each sport and are important to guide an intervention focused on injury prevention.

FACTORS ASSOCIATED TO PATELLAR TENDINOSIS IN ATHLETES: PROVIDING A BASE FOR INJURY MECHANISM AND PREVENTION

Background Patellar tendon abnormalities (PTA) are frequent in volleyball and basketball athletes. Tendon degeneration happens through chronic process, related to the amount of stress applied in musculoskeletal system. An appropriated mechanical behaviour of lower limb may be key factor to properly distribute forces in patellar tendon during landing. Identify biomechanical factors associated to patellar tendinosis process could guide preventive attitudes to athletes in risk of chronic dysfunction and/or tendon rupture. Objective To investigate the association of lower limb biomechanical factors to patellar tendon morphological abnormalities at ultrasound. Design Cross-sectional. Setting Institutional clinical care and sports facility. Participants 35 basketball and volleyball athletes participating on preseason assessment with mean age of 24.0±5.7 years, body mass of 88.9±13.3 kg and height of 1.9±0.1 m. Risk factor assessment Ankle dorsiflexion range (ADR), shank-forefoot alignment (SFA), iliotibial band flexibility (IBF), hip lateral rotators and abductors isometric strength, hip passive medial rotation range, patellar rotation and knee alignment in the frontal plane were measured during preseason assessment. Ultrasonographic evaluation was performed in both patellar tendons in longitudinal and transverse planes. Main outcome measurements Patellar tendon hypoechoic areas and thickness at ultrasound. Results The results showed that low ADR, high IBF and high SFA were associated to PTA. These three variables presented significant areas under ROC curve (P=.008; P=.011; P=.012, respectively). Based on ROC curve sensitivity and specificity values, cut-off points were determined. SFA presented the highest OR; 13.1 (2.1–296); with a cut-off point of 20o. ADR (cut-off point=36o) presented an OR of 4.10 (1.3–13.5) and IBF (cut-off point=-0.04o) presented an OR of 4.53 (1.2–21.6). Conclusions High shank-forefoot varus alignment, ankle dorsiflexion restriction and iliotibial band flexible were associated to PTA. These results show that biomechanical factors could participate on patellar tendon mechanical overload in athletes.

SCREENING ATHLETES WITH PATELLAR TENDINOSIS: CLINICAL INFORMATION TO GUIDE PREVENTIVE ATTITUDES

Background Patellar tendinosis is a degenerative condition that could lead to tendon rupture. Conservative treatment is long-term and surgery may be required to enhance tissue regeneration. Therefore, the athlete could have his/her successful career jeopardized. Some clinical tests, usually used in patellar tendon assessment, could be associated to patellar tendon morphologic abnormalities (PTA). However, their relationship to PTA is not established and they could be used in sports practice as a strategy for preventive care. Objective To investigate the association of VISA-P questionnaire, single-leg decline squat test and patellar tendon pain history to tendon morphological abnormalities at ultrasound. Design Cross-sectional study. Setting Athletes filled in VISA-P questionnaire, performed the single-leg decline squat test (SLDS) and informed about patellar tendon pain history. Athletes with Osgood-Schlater and/or Siding-Larsen-Johansson disease were excluded. An experienced examiner performed the ultrasonographic exam in tendon sagittal and transverse planes. Tendons that presented hypoechoic areas and thickness were considered as positive for morphological abnormalities. Participants 43 athletes (26 volleyball, 14 basketball, 3 running) participated in this study, 38 males and 5 females, mean age of 24.8±6.7 years, weight of 87.6±13.7 kg and height of 1.93 ±0.1 m. Risk factor assessment VISA-P, single-leg decline squat test and patellar tendon pain history. Main outcome measurements Patellar tendon hypoechoic areas and thickness at ultrasound. Results Significant associations to PTA were found. VISA-P showed an OR of 5.4 (1.3–26), SLDS of 3.8 (1.4–11) and pain history of 7.5 (1.6–42). Therefore, an athlete who presents a score under 80 points at VISA-P, for example, have 5.4 more chance to present PTA compared to an athlete that does not have PTA. Conclusions VISA-P, SLDS and patellar tendon pain history can be easily applied in clinical practice and should be used as a screening tool in sports modalities that present a high PTA prevalence.

NORMATIVE DATA FOR MUSCLE FLEXIBILITY IN MALE SOCCER PLAYERS

Background Muscular tightness is frequently postulated as an intrinsic risk factor for a muscle injury in soccer. Further, hamstring, iliopsoas and quadriceps flexibility measurements are of clinical relevance for monitoring recovery after such injury. Objective Describe normative data of flexibility for the hamstring, iliopsoas and quadriceps. Design Cross-sectional study. Setting The modified Thomas test was used to measure flexibility for iliopsoas and quadriceps. The passive knee extension test was used to determine the hamstring flexibility. The ICC of these tests range from 0.97 to 0.99. All these measurements were performed at Sports Injuries Prevention and Rehabilitation Laboratory. Participants 182 elite male soccer players participated in this study; the means for age were of 18.3±3.6 years, body mass of 73.3±8.5 kg and height of 1.78±10.6 m. Assessment of risk factors Hamstring, iliopsoas and quadriceps flexibility. Results For the iliopsoas and quadriceps flexibility the means were -6.76°± 5.7 and 55.2°±8.35 in the dominant leg (DL) and –7.6°±5.1 and 53.1°±8.2 in the non-dominant leg (NDL), respectively. The hamstring means were 134°±8.5 in the DL and 134.7°±8.3 in the NDL. The DL were significantly less flexible than the NDL for iliopsoas (P<.0001) and for the quadriceps the NDL were less flexible (P<.0001). Conclusions The study has provided normative data for a clinical test measuring flexibility of the hamstring, iliopsoas and quadriceps. The athletes had asymmetries between limbs for the MTT and had hamstring flexibility values similar to injured soccer players. Therefore, the flexibility assessment should be performed in preseason to guide preventive interventions and provide baseline values to rehabilitation parameters after a muscle strain.

Comparative analysis of knee valgus in athletes during takeoff and landing

Background The knee malalignment is a risk factor of injuries such as anterior cruciate ligament tear. Most studies that analyses the knee valgus in jump tasks, investigates only this pattern at landing. It would be interesting to study the knee valgus at takeoff, because at this specific moment the active components of the movement are the primary injury contributors. Objective to compare the frontal plane knee angle (FPKA) during takeoff and landing at countermovement jump in athletes. Design Observational cross sectional. Setting Volleyball and basketball players were evaluated at Minas Tennis Club and at Sports Prevention and Rehabilitation Laboratory (CENESP-UFMG). Participants 101 athletes, mean age 15.88 (0.35) years were included in this study. All participants were healthy, with no current complaints of lower limb injury or pain and no history of lower limbs previous surgery. Assessment of risk factors High-FPKA. Reflexive markers were located in ASIS, femoral condyles and in a middle point of the medial and lateral maleolus. Main outcome measurements The FPKA was determined in SIMI motion 2D software. Results The mean angle during takeoff was 3.020 and 3.13 0 for dominant and non-dominant leg. For landing, it was 2840 and 2210 respectively. There was no significant statistical differences between the two means on both legs (p=0.73 dominant leg and p=0.13 non-dominant leg). Meanwhile, the variance was greater in the impulsion analysis (37.2 right leg and 48.3 left leg) compared to landing (24.4 and 29.8 respectively). Conclusion The analysis of FPKA during takeoff provides data about the active contribution of certain variables in knee injuries and must be better understood. Differences between the FPKA during takeoff and landing were not found in this study, although in the first movement there was a major variance. This inconsistency may demand a more thorough investigation.

Correlation between isokinetic profile and knee injuries in male volleyball athletes

Background Knee injuries are prevalent in elite volleyball and their preventive management is still discussed. Isokinetic assessment is largely use in sports injury prevention; however few studies investigate the differences in the isokinetic profile of injured knees. These studies analyses the agonist/antagonist ratio and do not consider other parameters as fatigue index. Objective to investigate the differences between injured and non injured knee in the hamstring/quadriceps ratio and fatigue index in volleyball male athletes. Setting all testing took place in the Sports Injury Prevention and Rehabilitation Laboratory- LAPREV in elite volleyball. Participants 49 male (mean+SD age, 21.96+4.1; height, 196.5+0.06; body mass, 89.1+9.03) athletes were evaluated in this study, being 20 at injured group. Participants with lower-extremity surgery in the previous 6 months and pain during the isokinetic test were excluded. Assessment of risk factor: hamstring/quadriceps ratio at 60°/s and 300°/s and fatigue at 300°/s at the dominant knee with 90° of hip flexion. Main outcome measurements trauma and overuse knee injuries provided by questionnaire. Results Differences between groups were found just in hamstring fatigue (p=0.002). The means of this parameter were 63.1 and 55.6 for injured and non-injured group respectively. For quadriceps fatigue the means were 48.4 and 47.3 respectively. No differences were found in the ratio analysis between groups (p=0.403 for 60°/s and p=0.289 for 360°/s). The means were 199.4 and 203.5 for injured and non-injured groups at 60°/s and 157.4 and 168.6 respectively at 300°/s. Conclusion The results showed that the injured group has more hamstring fatigue compared to non-injured group. The ratio analysis does not reveal differences between groups. The fatigue analysis must be incorporated in the athletes assessment, because seems to be more informative about injury risk.