The aim of the study was to examine the effect of a comprehensive warm-up programme designed to reduce the risk of injuries in female youth football.

125 football clubs from Norway (65 clusters in the intervention group; 60 in the control group) were followed for one league season. This totalled 1892 female players aged 13-17 (1055 players in the intervention group; 837 players in the control group).

The intervention group were given a comprehensive warm-up programme to improve strength, awareness, and neuromuscular control during static and dynamic movements. Results were measured by injuries to the lower extremity (foot, ankle, lower leg, knee, thigh, groin, and hip).

The results demonstrated that 264 players had relevant injuries: 121 players in the intervention group and 143 in the control group. In the intervention group there was a significantly lower risk of injuries overall, overuse injuries, and severe injuries.

The authors concluded that although reduction in lower extremity injuries did not reach significance, the risk of severe injuries, overuse injuries, and injuries overall was reduced. This indicates that a structured warm-up programme can prevent injuries in young female football players.

BMJ 2008;337:a2469

Delayed onset of the vastus medialis obliquus (VMO) has often been linked with patellofemoral pain (PFP). Research has also suggested that lower leg movements play a role in patella tracking. Studies have also revealed that a motion control shoe could reduce rearfoot pronation in overpronators.  Using all of this information, the authors hypothesised that motion control shoes may help prevent PFP by controlling excessivepronation. This study compares the vasti muscle activities in people with excessive foot pronation when runningwith different trainers.

Twenty female subjects with rearfoot pronation >6° were selected. Testing involved treadmill running for 10 km on two separate days. The subjects wore a motion-control running shoe on one day and a neutral running shoe on the other. EMG activity of their right VMO and vastus lateralis (VL) were recorded. Their EMG onset timing and median frequency (MF) were compared between the two shoe conditions.

A more significant delay in VMO contraction onset of the running cycle occurred in the neutral shoe than in the motion control shoe. In the neutral shoe, the delay in VMO increased as mileage increased. This did not happen in the motion control shoe. A significant drop in MF of the quadriceps after the 10 km run in both shoes  was observed, and there was a larger drop in VMO MF when running with the neutral shoe. The findings suggest that the motion control shoe may facilitate a stable temporal activation of VMO during running.

British Journal of Sports Medicine 2009;43:943-947

Following an intial hamstring injury, re-injury is a common problem. The functional reasons for this remain unclear. This study looks at differences in swing phase running biomechanics and isokinetic strength, between the previously hamstring-injured and uninjured limbs of male athletes involved in sprint-based sports.

Athletes, underwent 3D motion analysis to determine bilateral joint kinematics and kinetics during submaximal sprinting. Various hip and knee isokinetic strength tests were performed bilaterally using a Biodex dynamometer. Peak torque (PT) and total work (TW; normalized to body mass) were collected isokinetically from concentric hamstrings (CH), concentric quadriceps (CQ), concentric hip flexors (CHF), and eccentric hamstrings (EH). Three PT and TW ratios were created, namely, CH/CQ, EH/CQ, and EH/CHF, and were compared between the previously injured and uninjured limbs.

The results show that lower limb swing phase kinematics and kinetics were similar. Only peak hip flexion angle in late swing was significantly reduced (1.9[degrees]) in the previously injured limb. EH PT was decreased and occurred at shorter hamstring lengths on the previously injured side, whereas CQ TW was increased by 13.6 Jkg-1. EH/CQ and EH/CHF ratios for PT and TW were reduced on the previously injured limbs.

The rearch concluded that although swing phase biomechanics of submaximal sprinting were similar between limbs, the previously injured hamstrings did display significant weakness eccentrically. Residual eccentric weakness may predispose this muscle group to reinjury during late swing, compared with the uninjured limb, because the functional eccentric demand on both limbs was similar. Furthermore, the EH/CHF ratios may better reflect muscle function during sprinting, having the potential to influence rehabilitation to prevent reinjury.

Medicine & Science in Sports & Exercise. 41(10):1942-1951, October 2009.

In this study, the effect of shoe degradation on running biomechanics by comparing the kinetics and kinematics of running in new and worn shoes was investigated. Three types of footwear using different cushioning technologies were compared.

24 runners (14 male and 10 female) were tested Pre and post 200 miles of road running in the smae pair of shoes. The runners were given either air/gel/spring cushioned trainers. Testing consisted of overground running at 4.5 m s^–1 on a 20-m laboratory runway; performance measured using a force platform and a motion capture system.

Stance time was calculated from force data. External loads were measured by maximum vertical force and loading rate. Kinematic changes were indicated by sagittal plane angles of the torso, hip, knee and ankle at critical events during the stance phase.

Results demonstrated that stance time increases in worn shoes. The torso displayed less maximum forward lean and less forward lean at toe-off , while the ankle displayed reduced maximum dorsiflexion and increased plantar flexion at toe-off  in worn shoes. No changes in the hip and knee angles. No between-group difference among the three footwear groups or condition by type interaction was found in any measured variables.

The results show that as shoe cushioning decreases, runners change their pattern of running to maintain constant external loads. The adaptation strategies to shoe degradation were unaffected by different cushioning technologies, suggesting runners should choose running shoes for reasons other than cushioning technology.

British Journal of Sports Medicine 2009;43:745-749

The aim of this study was to determine the clinical presentation of adolescent patellofemoral pain.

Reviews were carried out over a three year period, of all patients with patellofemoral pain (PFP) at a childrens hospital sports clinic.

101 patients (91 female) with 136 symptomatic knees were assessed. Mean age was 14.4 years. Knee pain was localized to the anteromedial or anterior region of the knee in 96% of patients and was typically produced with running (94%), jumping (92%) and stair use (69%). On physical examination there was usually a non antalgic gait (99%), no patellofemoral crepitation (98%), normal lower extremity angular (84%) and rotational alignment (94%), with no foot malalignment (>97%). The medial patellofemoral ligament (MPFL) was the most palpably tender area of the knee in 98% of patients. During “lateral apprehension” testing, 89% had pain at the MPFL, but not true apprehension. A “J-sign” was present at terminal knee extension in 65%. Mean Q-angle was 18.7°. Means of all radiographic measures were within normal ranges.

Most commonly, patients complained of anterior/anteromedial knee pain of insidious onset during running and jumping. The most consistent physical findings were focal tenderness at the MPFL, positive terminal J-sign, and an elevated Q-angle. Most patients required only nonsurgical treatments, but 18% underwent surgical interventions for persistent pain.

J Child Orthop. 2008 August; 2(4): 269–277 

The position of the trunk and the knee during non-contact ACL injuries has not been examined before.

10 female, 7 male and 6 female controls were used. The participants were analysed for coronal and sagittal plane movement during landing and cutting tasks.

The results show that lateral trunk and knee abduction angles were higher in females than males during ACL injury. They also trended to be higher then the female control group. Female ACL-injured athletes also demonstrated less forwards lean than the female controls.

The study concludes that lateral trunk and knee abduction motion are important factors of the ACL injury mechanism in female athletes.

BJSM, 2009; 43: 417-422

The pathology,  etiology and natural course of Achilles tendinopathy are not yet understood completely. Due to this, many forms of treatment have been used, with mixed success. Extracorporeal shockwave therapy (ESWT) has been proposed in the treatment of these tendinopathies in recent years having already shown positive results in the short-term.

This study aims to evaluate the effectiveness of ESWT in treating Achilles tendinopathies in the long-term. 105 patients (with 127 affected tendons) aged between 18 and 74 years were used in this study. All patients were diagnosed using ultrasonography, magnetic resonance imaging or X-rays. Shock wave treatment was applied using an electromagnetic shock wave generator. Subjects recieved on average four sessions (minimum three, maximum five), at a 2/7-day interval. Assessments took place before therapy and two months after the last treatment session. Medium term assesment between 6-12 months and again at 13 to 24 months were also undertaken.A satisfactory result was obtained in 47.2% of cases (60 out of 127 tendons) at two-months follow-up, which increased to 73.2% at medium-term follow-up (93 out of 127 tendons), and then reaching 76% in the last evaluation (92 out of 121 tendons).

The outcome of the described shock wave treatment appears to be satisfactory and confirms the role of this alternative treatment in the management of the tendon disorders.

Journal of Sports Medicine and Physical Fitness 2009 June;49(2):171-76

The aim of this study was to determine if there is a difference in hamstring length between patients with and without patellofemoral (pf) pain syndrome aged 18 to 35 years.

The pf group contained six males and 5 females who had been diagnosed with patellofemoral pain syndrome and the control group contained 13 males and 12 females who were completely asymptomatic.

Hamstring length was assessed using the passive knee extension method to measure popliteal angle.

The mean (standard deviation) values for hamstring length were 145.6 (8.7)° for patients with patellofemoral pain syndrome and 153.7 (10.1)° for the asymptomatic controls.

This study found that patients with patellofemoral pain had shorter hamstring muscles than asymptomatic controls. It is not clear whether this is a cause or effect of the condition. Further research is suggested to study how hamstring length changes with rehabilitation, and the relationship with pain.

Physiotherapy, Volume 95, Issue 1, Pages 24-28

This study looked at the neuromuscular control, strength and range of motion at the hip joint in patients with patellofemoral pain (PFP) syndrome. 

The study used 37 participants in total, 10 with pfp and 27 pain-free individuals.

Electromyographic activity of the vasti muscles (quads) and the anterior and posterior gluteus medius (GM) were recorded using either surface electrodes or fine wire electrodes while the participant completed a stair-stepping task. Hip and trunk side flexion strength were assessed using a hand-held dynamometer. Hip range of motion was measured with an inclinometer. Pain and disability measures were recorded for the PFP participants. Results indicated that individuals in the PFP group had a delayed activation of gluteus medius. They also displayed delayed firing of vastus medialis oblique, compared with vastus lateralis and a decrease in trunk side flexion strength.

This study reiterates the importance of re-training both gluteus medius and VMO in patients with patellofemoral pain.

British Journal of Sports Medicine 2009;43:584-588

Damaged cartilage covering the articular surfaces of the knee joint can be a very difficult condition to treat for orthopaedic surgeons; Recently, second-generation autologous chondrocyte implantation (ACI) has been used and has produced satisfactory results in the short-term.

34 of an original 38 patients treated for full-thickness patellofemoral chondral lesions with second-generation ACI, were assessed 5 years post-operation. 8 patients had received a secondary arthroscopy or biopsy. These revealed the repaired surface to be nearly normal with biopsy samples characterized as hyaline-like in appearance.

Hyaluronan-based scaffold seeded with autologous chondrocytes can be a viable treatment for patellofemoral chondral lesions.

All the scores used demonstrated a statistically significant improvement at 2 and 5 years’ follow-up

Am J Sports Med June 2009 vol. 37 no. 6 1083-1092