Abstract Background Chronic musculoskeletal pain is common in adolescents, and it has been shown that adolescents with pain may become young adults with pain. Pain often coincides with psychosomatic symptoms in adults, but little is known about longitudinal associations and predictors of pain in adolescents. The aim was to investigate chronic musculoskeletal pain and its associations with health status, sleeping problems, stress, anxiety, depression, and physical activity in 16-year-old students at baseline, and to identify risk factors using a three-year follow-up. Methods This was a longitudinal study of 256 students attending a Swedish upper secondary school. Questionnaires regarding chronic musculoskeletal pain and distribution of pain (mannequin), health status (EQ-5D-3 L), sleeping problems (Uppsala Sleep Inventory), stress symptoms (single-item question), anxiety and depression (Hospital Anxiety and Depression Scale), and physical activity (International Physical Activity Questionnaire) were issued at baseline and follow-up. Student’s t-test and chi2 test were used for descriptive statistics and logistic regression analyses were used to study associations between chronic pain and independent variables. Results Fifty-two out of 221 students at baseline (23.5%) and 39 out of 154 students at follow-up (25.3%) were categorized as having chronic musculoskeletal pain. Chronic musculoskeletal pain at follow-up was separately associated with reporting of an EQ-5D value below median (OR 4.06, 95% CI 1.83–9.01), severe sleeping problems (OR 3.63, 95% CI 1.69–7.82), and possible anxiety (OR 4.19, 95% CI 1.74–10.11) or probable anxiety (OR 3.82, 95% CI 1.17–12.48) at baseline. Similar results were found for associations between chronic musculoskeletal pain and independent variables at baseline. In multiple logistic regression analysis, chronic musculoskeletal pain at baseline was a predictor of chronic musculoskeletal pain at follow-up (OR 2.99, 95% CI 1.09–8.24, R2 = 0.240). Conclusion Chronic musculoskeletal pain at baseline was the most important predictor for reporting chronic musculoskeletal pain at the three-year follow-up, but a worse health status, severe sleeping problems, and anxiety also predicted persistence or development of chronic musculoskeletal pain over time. Interventions should be introduced early on by the school health services to promote student health.

A new device to increase the medial-to-lateral hamstring and quadriceps co-contraction ratios in female athletes

Background/Purpose: Chronic widespread pain (CWP), one of the hallmarks of fibromyalgia, is not uncommon in adolescents and it has previously been shown that adolescents with pain often become young adults with pain. CWP often co-varies with anxiety, depression, and stress symptoms in adults, but the knowledge regarding this is small in youth and young adults.The aim was to study the associations between CWP, anxiety, depression and stress in adolescents attending first year of high school.Methods: A computerized questionnaire to 296 adolescents attending Swedish high school, with validated questions regarding presence and distribution of pain (Epipain mannequin), stress symptoms (ELO question), anxiety and depression (Hospital Anxiety and Depression Scale – HADS), and health related quality of life (HRQL as measured by EQ5D). Pain was considered chronic when persistent for more than three months, and the subgroup CWP was defined according to the 1990 ACR criteria for fibromyalgia. Statistical analyses in SPSS v21 with comparison of means by Student’s t-test and proportions by chi2-test or Fischer’s exact test.Results: 257 (87%) out of 296 eligible students, mean (SD) age 16.1 (0.7) and 65.8% girls, responded to the questionnaire. Prevalence of chronic pain was 20.8% and that of the subgroup CWP was 4.7%, without any gender differences (boys 18.2% vs girls 22.2%; p=0.224, and 3.4% vs 5.4%; p=0.692). High level (4 or 5 on a 5 point scale) of stress symptoms were less common in boys (16.0% vs 28.2%; p=0.015), as was possible or probable anxiety (17.1% vs 44.4%; p<0.001), but not depression (10.3% vs 12.5%; p=0.764). Students with high level of stress reported CWP five times more often than those with less stress (30.4% vs 5.8%; p=0.001). Students with probable anxiety reported CWP ten times more often than students with no anxiety (17.6% vs 1.8%; p=0.001), and CWP was also more common, but not statistically significant, in students with probable depression (20.0% vs 3.1%; p=0.163). Those reporting CWP had significantly lower HRQL (0.58 vs 0.87; p=0.038) than students with no chronic pain.Conclusion: The high prevalence of chronic pain and the strong associations between CWP and reports of stress and anxiety in adolescents highlights that a multifactorial background to chronic pain must be considered early in life. An apparent lower score in EQ5D also indicates that the presence of CWP has an marked impact on HRQL also in adolescents.

Background: Impaired hand function is common in patients with arthritis and it affects performance of daily activities; thus, hand exercises are recommended. There is little information on the extent to which the disease affects activation of the flexor and extensor muscles during these hand-dexterity tasks. The purpose of this study was to compare muscle activation during such tasks in subjects with arthritis and in a healthy reference group.Methods: Muscle activation was measured in m. extensor digitorium communis (EDC) and in m. flexor carpi radialis (FCR) with surface electromyography (EMG) in women with rheumatoid arthritis (RA, n = 20), hand osteoarthritis (HOA, n = 16) and in a healthy reference group (n = 20) during the performance of four daily activity tasks and four hand exercises. Maximal voluntary isometric contraction (MVIC) was measured to enable intermuscular comparisons, and muscle activation is presented as %MVIC.Results: The arthritis group used a higher %MVIC than the reference group in both FCR and EDC when cutting with a pair of scissors, pulling up a zipper and-for the EDC-also when writing with a pen and using a key (p < 0.02). The exercise "rolling dough with flat hands" required the lowest %MVIC and may be less effective in improving muscle strength.Conclusions: Women with arthritis tend to use higher levels of muscle activation in daily tasks than healthy women, and wrist extensors and flexors appear to be equally affected. It is important that hand training programs reflect real-life situations and focus also on extensor strength.

The aim of this study was to evaluate tracking performance when an extra reference block is added to a basic block-matching method, where the two reference blocks originate from two consecutive ultrasound frames. The use of an extra reference block was evaluated for two putative benefits: (i) an increase in tracking performance while maintaining the size of the reference blocks, evaluated using in silico and phantom cine loops; (ii) a reduction in the size of the reference blocks while maintaining the tracking performance, evaluated using in vivo cine loops of the common carotid artery where the longitudinal movement of the wall was estimated. The results indicated that tracking accuracy improved (mean = 48%, p < 0.005 [in silico]; mean = 43%, p < 0.01 [phantom]), and there was a reduction in size of the reference blocks while maintaining tracking performance (mean = 19%, p < 0.01 [in vivo]). This novel method will facilitate further exploration of the longitudinal movement of the arterial wall.

INTRODUCTION: In previous studies, stance widths are most often determined as a percentage of shoulder width, where 70% of shoulder width is considered a narrow stance width and 140% of shoulder wi ...

This study showed that increased grip force and muscle activity in the swing is associated with shot length. These results indicate that both maximal grip force and muscle activity in the EDC can be important factors for increasing shot length, and that a highly coordinated pattern between these muscles are useful in order to maximize shot distance.

Unilateral Strength Training With Maximal Velocity Improves Lower Body Power Outcome And Movement Velocity

Objective: Balance between flexor and extensor muscle activity is essential for optimal function.The purpose of this pilot study was to compare the relationship between maximum finger flexion force and maximum finger extension force in women with rheumatoid arthritis and healthy women.Methods: Twenty healthy women (median age 61 years) and 20 women with rheumatoid arthritis (median age 59.5 years, median disease duration 16.5 years) were included in the study.Finger extension force was measured with an electronic device, EX-it, and finger flexion force using Grippit.The Grip Ability Test and the score from the patient-reported outcome Disability Arm Shoulder and Hand were used to evaluate activity limitations.Results: Patients with rheumatoid arthritis showed significantly decreased hand function compared with healthy controls.A correlation was found between extension force and flexion force in the healthy group (r = 0.65, p = 0.002), but not in the rheumatoid arthritis group (r = 0.25, p = 0.289).Conclusion: Impaired hand function appears to influence the relationship between maximum finger flexion and extension force.This study showed a difference in the relationship between maximum finger flexion and extension force in healthy controls and those with rheumatoid arthritis.

Equipment used in sports is of great importance, especially when the equipment is in direct contact with the athlete or is important for safety.In the sport kitesurfing environmental factors and the equipment design are crucial for the comfort and safety.The participants' choice and opinion of equipment can show which factors are considered most important for the performance and to reduce risk for injury.This study has evaluated self-reported information from the participants about what equipment they use, comfort of the equipment and if the equipment has contributed to any injuries.The methods used were questionnaires (n=206) and interviews (n=17), which in combination allows to assess the problem both quantitatively and qualitatively.The results showed that supported leading edge kites are most frequently used, with a waist harness and foot straps to attach the feet.The choice of kite type was mainly based on the discipline of riding for the respondent.Some issues concerning comfort of riding and injury risk the respondents did relate to the design of harness and foot straps.The information from this study can be used for development strategies for industry manufacturers and for further studies in the area of equipment design and biomechanics.

evaluation methods for evaluation of rehabilitation and interventions.There is also a need for further knowledge of the dynamic action of skeletal muscle and the relation between muscle morphology and muscle force.The force that can be generated is dependent on the muscle architecture; these architectural parameters can be studied non-invasively with US.By using US it is possible to obtain detailed, dynamic information on the muscle architecture.In order to assess how disease influences muscle morphology and function, it is necessary to establish baseline knowledge concerning normal forearm muscles.The general aim of this book chapter was to further our knowledge about biomechanics of the hand, RA patient, non-invasive evaluation methods used for evaluation of rehabilitation interventions and muscle biomechanics will be further presented. Biomechanics of the handIt is important to understand the biomechanics of the hands and fingers as well as the muscle architecture and structure in order to develop new evaluation methods for finger extension force.The construction of the hand is quite complicated, including 29 joints, 27 bones and more than 30 muscles and tendons working together for range of motion (ROM), performing perception and force production. The construction of the handThe metacarpophalangeal (MCP) joints II-V are condyloid joints that allow for movement in two planes, flexion/extension or adduction/abduction.The ROM in the joints is approximately 30-40 degrees extension, 70-95 degrees flexion and 20 degrees adduction/abduction.Ligaments connect the bones and provide stability of the joints; in the hand there are numerous ligaments that stabilize the joints.To provide stability to the metacarpal bones, there are ligaments working in conjunction with a thick tissue located in the palm (the palmar aponeurosis).Muscles that control the hand and have their origin located near the elbow are called the extrinsic muscles.The tendons of these muscles cross the wrist and are attached to the bones of the hand.The large muscles that bend (flex) the fingers originate from the medial aspect of the elbow.The large muscles that straighten (extend) the fingers originate from the lateral aspect of the elbow.The extrinsic muscles are responsible for powerful grip ability.In addition to these large muscles, there are smaller muscles in the hand, intrinsic muscles, that flex, extend, abduct (move outwards) and adduct (move inwards).The agonist for extension in fingers II-V is the muscle extensor digitorum communis (EDC).This muscle originates at the lateral epicondyle of humerus; the muscle is connected to phalanges II-V by four tendons, which glide over the MCP-joints articulations.The tendons divide into three parts.The main part is attached to the extensor hood and two collateral ligaments are attached at the lateral and medial parts of the fingers.The extensor hood covers the whole phalange and is formed from the extensor digitorum tendon and fibrous tissue.The extension ability in the MCP-, proximal interphalangeal-, and distal interphalangeal joints are produced by EDC, interossei and lumbricales muscles (Smith 1996;Marieb 1997).Finger extension force is dependent on the wrist position.However, at the present time there is no consensus for the optimal wrist angle for finger extension force measurement.Researchers believe that a wrist position between 10-30 degrees is suitable for finger extension measurements (Li 2002).www.intechopen.

The results from this study show that training strategies can lead to improved flexibility and stability in golfers during the off season, however maintaining these improvements, particularly flexi ...

Equipment used for high-risk sports, such as kitesurfing, needs to be efficient for the intended use and the user, and thus meet the mechanical demands and provide sufficient safety. Accidents related to kitesurfing occur, and the consequences are sometimes catastrophic. One important factor is the equipment design, which can influence the type and number of injuries due to insufficient safety systems. The aim of this study was to investigate how the design of kitesurfing equipment can affect safety issues from a usability perspective in relation to the task of preparation. A focus group of 6 subjects analyzed the task of preparing kitesurfing equipment for riding, using the evaluation methods Enhanced Cognitive Walkthrough (ECW) and Predictive Use Error Analysis (PUEA). From the evaluation, a list of plausible usability problems was identified together with proposed design guidelines. The results showed that usability problems occur during preparation. In total 35 usability problems were found, of which 11 (4 from ECW and 7 from PUEA) have a great impact on safety. These 11 problems were hard to detect for the user and could result in serious consequences for the kitesurfers during riding. The analysis resulted in some general guidelines that are possible to implement on different types of kites. To conclude, education and improved design of the equipment are essential to increase the safety of the sport.

Participation in sporting activities can lead to injury. Sport injuries have been widely studied in many sports including the more extreme categories of aquatic board sports. Kitesurfing is a relatively new water surface action sport, and has not yet been widely studied in terms of injuries and stress on the body. The aim of this study was to get information about which injuries that are most common among kitesurfing participants, where they occur, and their causes. Injuries were studied using an international open web questionnaire (n=206). The results showed that many respondents reported injuries, in total 251 injuries to knee (24%), ankle (17%), trunk (16%) and shoulders (10%), often sustained while doing jumps and tricks (40%). Among the reported injuries were joint injuries (n=101), muscle/tendon damages (n=47), wounds and cuts (n=36) and bone fractures (n=28). Also environmental factors and equipment can influence the risk of injury, or the extent of injury in a hazardous situation. Conclusively, the information from this retrospective study supports earlier studies in terms of prevalence and site of injuries. Suggestively, this information should be used for to build a foundation of knowledge about the sport for development of applications for physical training and product development.

INTRODUCTION: Soccer is the world’s most popular team sport with over 240 million players around the world. About 20 million of the 240 million players are women and 80% of these women are adolesce ...

Background:Impaired grip ability in RA is due to reduced strength in the flexor muscles as well as by dysfunctional extensor muscles leading to inability to open the hand. Furthermore the extensor ...