In haemophiliacs, the physical condition, muscular strength, aerobic resistance, anaerobic resistance and proprioception have all diminished. Muscle atrophy and instability, being more vulnerable to stressful motor demands, increase the risk of lesion and establish a vicious circle that is hard to break: pain, immobility, atrophy, articular instability and repeated bleeding episodes. In haemophilia, physical and/or sporting activities were not recommended until the seventies. Nowadays, the overall policy is to recommend certain physical activities, especially swimming, to improve the patient's quality of life, thanks to prophylaxis programmes. The objective of this study is to perform a systematic review of the exercise and sporting activities recommended for haemophiliacs. Experimental and observational studies and clinical assays about rehabilitation for haemophiliacs with exercise and sporting activities have been included. The relevant studies were identified in Medline, Cinahl, Embase and SportDiscus, and key words were: haemophilia, exercise and sport (with no language restrictions). Works were independently analysed by reviewers and the following were identified: of 3603 studies, 103 were included in this review: 29 (28.15%) were experimental, 27 (26.21%) were observational and 47 (45.63%) were clinical. Physiotherapy, physical activity and sport are basic elements to improve quality of life and the physical condition, increase strength and resistance and to reduce the risk of musculoskeletal lesions and to prevent haemophilic atrophy. In general, professionals in haemophilia believe that regular exercise and rehabilitation with physiotherapy is fundamental, particularly in countries where replacement therapy is not readily available.

Musculoskeletal disorders in haemophiliacs represent the highest percentage of lesions, giving rise to haemophilic arthropathy (HA) which predominantly affects lower limbs, influencing postural control, standing and walking. Leading a sedentary lifestyle seems to influence strength and muscular resistance in haemophiliacs which, in turn, are related to articular stability and the prevention of articular degenerative processes. The objective of this work was to study alterations in balance to subsequently evaluate the appropriate therapeutics and how this influences the development of arthropathy. Twenty-five haemophiliacs with HA, 25 haemophiliacs without HA (NHA) and 25 healthy control subjects (CTL) took part in this study. Tests were performed on a force platform and the subjects remained as still as possible for 30 s under different conditions: (i) bilateral stance with eyes open; (ii) bilateral stance with eyes closed; (iii) right unilateral stance; and (iv) left unilateral stance. The results of these tests indicated significant differences (P < 0.05) between the groups HA, NHA and CTL. The HA group presented worse results for both unilateral and bilateral stance when compared with the other two cohorts. Surprisingly, the NHA group displayed a worse balance than the controls. A single calculated parameter (mean frequency) did not show significant differences. This apparently indicates the absence of pathology in the nervous system in relation to postural control. The results suggest that our patients should participate in physical exercise programmes, rehabilitation and physiotherapy to improve their postural control.

Screen media usage, sleep time and socio-demographic features are related to adolescents' academic performance, but interrelations are little explored. This paper describes these interrelations and behavioral profiles clustered in low and high academic performance. A nationally representative sample of 3,095 Spanish adolescents, aged 12 to 18, was surveyed on 15 variables linked to the purpose of the study. A Self-Organizing Maps analysis established non-linear interrelationships among these variables and identified behavior patterns in subsequent cluster analyses. Topological interrelationships established from the 15 emerging maps indicated that boys used more passive videogames and computers for playing than girls, who tended to use mobile phones to communicate with others. Adolescents with the highest academic performance were the youngest. They slept more and spent less time using sedentary screen media when compared to those with the lowest performance, and they also showed topological relationships with higher socioeconomic status adolescents. Cluster 1 grouped boys who spent more than 5.5 hours daily using sedentary screen media. Their academic performance was low and they slept an average of 8 hours daily. Cluster 2 gathered girls with an excellent academic performance, who slept nearly 9 hours per day, and devoted less time daily to sedentary screen media. Academic performance was directly related to sleep time and socioeconomic status, but inversely related to overall sedentary screen media usage. Profiles from the two clusters were strongly differentiated by gender, age, sedentary screen media usage, sleep time and academic achievement. Girls with the highest academic results had a medium socioeconomic status in Cluster 2. Findings may contribute to establishing recommendations about the timing and duration of screen media usage in adolescents and appropriate sleep time needed to successfully meet the demands of school academics and to improve interventions targeting to affect behavioral change.

In the general population, the degenerative processes in joints are directly related to adult age, and osteoarthrosis represents the most frequent musculoskeletal alteration. In the haemophilic patient, the degenerative processes in the joint begin at very early ages, and are directly related to musculoskeletal bleeding episodes, which are occasionally subclinical and constitute haemophilic arthropathy. In the haemophilic patient, arthropathy constitutes the most frequent, severe and disabling pathology, and its assessment includes muscular force-related parameters. We have studied the value of Maximum Isometric Voluntary Contraction in the quadriceps femoris of 46 subjects, 28 haemophiliacs (16 severe, eight moderate and four mild) and 18 healthy individuals with a view to establishing appropriate values of force and to restoring physical therapy recommendations. The maximum force values were significantly greater (P < 0.001) in the healthy individuals group. The mild haemophiliacs group also presented significant differences of force (P < 0.05) in relation to the severe and moderate haemophilic patient groups. The mild and severe haemophilia patients presented greater fluctuations of force (P < 0.001) than the control group, the haemophilia group have a minor skill to produce constant force. The seriousness of the arthropathy in the knee is directly related to diminished values of maximum force. Our work evidences that patients with severe haemophilia present a greater degree of arthropathy in relation to moderate and mild haemophilia patients. Haemophilic arthropathy is associated with muscular atrophy and strength deficit. In haemophilic patients, the deficit of maximum force and the presence of fluctuations may suggest an increased risk of bleeding during physical activities and the need to programme specific physical therapy guidelines which increase muscular power through resistance training.

Study design: Cross-sectional validation study. Objectives: The goals of this study were to validate the use of accelerometers by means of multiple linear models (MLMs) to estimate the O 2 consumption (VO 2 ) in paraplegic persons and to determine the best placement for accelerometers on the human body. Setting: Non-hospitalized paraplegics' community. Methods: Twenty participants (age ¼ 40.03 years, weight ¼ 75.8 kg and height ¼ 1.76 m) completed sedentary, propulsion and housework activities for 10 min each. A portable gas analyzer was used to record VO 2 . Additionally, four accelerometers (placed on the non-dominant chest, non-dominant waist and both wrists) were used to collect second-by-second acceleration signals. Minute-byminute VO 2 (ml kg À1 min À1 ) collected from minutes 4 to 7 was used as the dependent variable. Thirty-six features extracted from the acceleration signals were used as independent variables. These variables were, for each axis including the resultant vector, the percentiles 10th, 25th, 50th, 75th and 90th; the autocorrelation with lag of 1 s and three variables extracted from wavelet analysis. The independent variables that were determined to be statistically significant using the forward stepwise method were subsequently analyzed using MLMs. Results: The model obtained for the non-dominant wrist was the most accurate (VO 2 ¼ 4.0558 À0.0318Y 25 þ 0.0107Y 90 þ 0.0051 Y ND2 À0.0061Z ND2 þ 0.0357VR 50 ) with an r-value of 0.86 and a root mean square error of 2.23 ml kg À1 min À1 . Conclusions: The use of MLMs is appropriate to estimate VO 2 by accelerometer data in paraplegic persons. The model obtained to the non-dominant wrist accelerometer (best placement) data improves the previous models for this population.