Semiprofessional players have a higher prevalence of an increased α angle in the kicking leg than the amateur group at the same age. The kicking leg is predisposed for FAI.

BackgroundFemoroacetabular impingement (FAI) is predominant in young male athletes, but not much is known about gait differences in cases of increased hip alpha angles. In our study, the hip alpha angle of Nötzli of soccer players was quantified on the basis of magnetic resonance imaging (MRI) with axial oblique sequences. The aim of the current study was to compare the rearfoot motion and plantar pressure in male semiprofessional soccer players with increased alpha angles to age-matched amateur soccer players.MethodsIn a prospective analysis, male semiprofessional and amateur soccer players had an MRI of the right hip to measure the alpha angle of Nötzli. In a biomechanical laboratory setting, 14 of these participants in each group ran in two shoe conditions. Simultaneously in-shoe pressure distribution, tibial acceleration, and rearfoot motion measurements of the right foot were performed.ResultsIn the semiprofessional soccer group, the mean value of the alpha angle of group was 55.1 ± 6.58° (range 43.2-76.6°) and 51.6 ± 4.43° (range 41.9-58.8°) in the amateur group. In both shoe conditions, we found a significant difference between the two groups concerning the ground reaction forces, tibial acceleration, rearfoot motion and plantar pressure parameters (P < 0.01, P < 0.05, P = 0.04). Maximum rearfoot motion is about 22% lower in the semiprofessional group compared to the amateur group in both shoe conditions.ConclusionsThis study confirmed that semiprofessional soccer players with increased alpha angles showed differences in gait kinematics compared to the amateur group. These findings support the need for a screening program for competitive soccer players. In cases of a conspicuous gait analysis and symptomatic hip pain, FAI must be ruled out by further diagnostic tests.

In the present study, we examined the influence of shoe lacing on foot biomechanics in running. Twenty experienced rearfoot runners ran in six different lacing conditions across a force platform at a speed of 3.3 m . s(-1). Foot pronation during contact, tibial acceleration, and plantar pressure distribution of the right leg were recorded. The test conditions differed in the number of laced eyelets (1, 2, 3, 6 or 7) and in lacing tightness (weak, regular or strong). The results show reduced loading rates (P < 0.05) and pronation velocities (P < 0.01) in the tightest and highest lacing conditions. The lowest peak pressures under the heel and lateral midfoot (P < 0.01) were observed in the high (seven-eyelet) lacing pattern. Regular six-eyelet cross-lacing resulted in higher loading rates (P < 0.05) and higher peak heel pressures (P < 0.01) than seven-eyelet lacing, without any significant differences in perceived comfort. The low lace shoe conditions resulted in lower impacts (P < 0.01) and lower peak pressures under metatarsal heads III and V (P < 0.01), which is probably induced by the foot sliding within the shoe. A firm foot-to-shoe coupling with higher lacing leads to a more effective use of running shoe features and is likely to reduce the risk of lower limb injury.

MRI evidence and clinical examination suggest that cam impingement is more common in elite athletes in comparison to non-athletes. At a professional level, the intense practice of track and field athletics is susceptible for FAI.

Nordic walking (NW) was compared with walking (W) and running (R) with respect to upper and lower limb injury risks. 24 NW-instructors performed W, NW, and R trials on a runway covered with artificial turf at controlled speeds. Foot pronation and ground reaction forces were measured as well as shock wave transmission to the right wrist. Comparison of NW and W shows similar results for all of the four chosen velocities (5 km/h, 7 km/h, 8 km/h, 8.5 km/h). Except for the 2nd peak of the vertical ground reaction force, NW results in higher loading rates and horizontal forces as well as higher pronation and pronation velocity values as compared with W. Wrist acceleration values up to 7.6 times gravitational acceleration were recorded in NW. Compared with R at the same speeds (8 km/h and 8.5 km/h), NW can be recommended as low impact sport with 36% lower loading rates and 59% lower pronation velocities. However, the high wrist accelerations in NW reveal that the upper extremities are exposed to considerable repetitive shocks, which may cause overuse injuries of the upper extremities. Thus, additional preventive exercises for the upper limb muscles are recommended as well as using shock absorbing walking poles.

Background The sequence of blocked balance training (BT) followed by blocked plyometric training (PT) showed greater improvements in physical performance than vice versa and is explained by a preconditioning effect of BT-related adaptations on subsequent adaptations induced by PT. However, it remains unclear whether beneficial effects can also be induced using alternating instead of blocked BT and PT exercise sequences. Thus, we examined the effects of a blocked versus an alternated sequence of BT and PT on physical performance in trained individuals. Methods Twenty young soccer players (13 years) were randomly assigned to a blocked ( n = 10) or an alternated ( n = 10) intervention group. Both groups trained balance and plyometric exercises for six weeks (two sessions/week). The exercises were conducted in a blocked (three weeks of BT followed by three weeks of PT) or an alternated sequence (weekly change of BT and PT). Assessment of pre- and post-training performance included measures of balance, muscle power, speed, and agility. Results Mainly significant main effects of Test (i.e., pre- to post-test improvements) were observed for the Y-balance test ( p ≤ 0.014, 1.3 ≤ Cohen’s d ≤ 1.81), the squat jump ( p = 0.029, d = 1.36), the countermovement jump ( p = 0.002, d = 2.21), the drop jump ( p = 0.004, d = 1.96), the split times/total time over 15-m sprinting ( p ≤ 0.001, 2.02 ≤ d ≤ 3.08), and the figure-T agility run ( p < 0.001, d = 3.80). Further, tendencies toward significant Test x Group interactions were found for several items of the Y-balance test and for SJ height in favor of the blocked BTPT group. Conclusions Our results indicate that the combined training of balance and plyometric exercises is effective to improve proxies of physical performance in youth soccer players. In addition, there is a limited advantage in some parameters of balance and muscle power for the blocked as compared to the alternated sequence of BT and PT.

The purpose of this article was to evaluate the different techniques of operative treatment of primary synovial chondromatosis (PSC) of the hip. We performed a systematic review of literature of PSC and also present one case report about arthroscopic treatment of PSC. Our study compares both established operative procedures, open versus arthroscopic surgery, and shows each advantages and complications. One hundred and forty-seven publications were found in a PubMed literature review searching the terms: "synovial chondromatosis", "synovial osteochondromatosis", "synovial metaplasia" and "hip". All included studies were divided into open surgery or arthroscopic surgery concerning the therapeutic strategy and the corresponding results. We could find a total number of 3 reviews about PSC of the hip relating to operative procedures. One patient presented to our outpatient clinic with PSC. After other pathologies causing hip pain were excluded, the patient underwent hip arthroscopy with excision of the loose bodies and partial synovectomy. Diagnosis of PSC was confirmed by histopathology. The patient was examined before and one year after surgery with the Visual Analogue Scale (VAS) and the Hip Outcome Score (HOS ADL). Resecting PSC by hip arthroscopy is a minor surgical, but demanding procedure with minimal risks, even useful in the treatment of elderly patients with moderate osteoarthritis.

BACKGROUND: Total hip arthroplasty (THA) is a safe and successful procedure for the treatment of osteoarthritis. One of the most common postoperative problems remains persistent hip pain. The arthroscopic evaluation of persistent hip pain following THA can be a valuable diagnostic tool in a select number of patients when carried out by experts in this technique. OBJECTIVE: Indication for arthroscopy was persistent pain after THA. Inclusion criteria were an absence of radiological loosening and a sterile aspiration 6 weeks before arthroscopy. Hip joint function and pain were evaluated pre-and postoperatively using the visual analogue scale (VAS) and the Hip Outcome Score (HOS), which scored the activities of daily living (ADL), and a sports subscale. METHODS: 5 patients (3 female, 2 male) with an average age of 60.2 ± 4.27 years (range 51-72 years) were included in the study. Arthroscopy with biopsy, adhesiolysis and psoas tendon release was performed 21.0 ± 21.97 months (range 6-57 months) after primary hip replacement. RESULTS: Pathological findings were prosthetic joint infection (two cases), impingement between acetabular component and psoas tendon (two cases), adhesions of the periprosthetic tissue (one case). The patients achieved a significant improvement of the Hip Outcome Score (HOS), from an average of 45.6 ± 22.5 (range 14.0-63.1) to 76.5 ± 3.8 (range 41.0-89.4, P = 0.016). Evaluation of the VAS showed a significant improvement from a preoperative value of 8.8 ± 0.5 to a postoperative value of 3.4 ± 1.0 (P = 0.001). CONCLUSION: Hip arthroscopy provides a minimal-invasive tool for diagnosis and therapy. In cases of persistent pain after THA, standard diagnostic procedures should be utilised. Arthroscopy of a hip post-THA would be highly specialised. As a next step, arthroscopy helps the diagnosis and therapy of persistent pain after THA.