Jing Xian Li

Ottawa Panel evidence-based clinical practice guidelines for the management of osteoarthritis in adults who are obese or overweight.

Background and Purpose The objective of this review was to construct an updated evidence-based clinical practice guideline on the use of physical activity and diet for the management of osteoarthritis (OA) in adults (>18 years of age) who are obese or overweight (body mass index ≥25 kg/m2). Data Sources Articles were extracted from the following databases: MEDLINE, EMBASE (Current Contents), SPORTDiscus, SUM, Scopus, CINAHL, AMED, BIOMED, PubMed, ERIC, the Cochrane Controlled Trials, and PEDro. Study Selection The Ottawa Panel and research assistance team strictly applied the inclusion and exclusion criteria from previous Ottawa Panel publications. Data Extraction An a priori literature search was conducted for articles related to obesity and OA of the lower extremities that were published from January 1, 1966, to November 30, 2010. Inclusion criteria and the methods to grade the recommendations were created by the Ottawa Panel. Data Synthesis Recommendations were graded based on the strength of evidence (A, B, C, C+, D, D+, or D−) as well as experimental design (I for randomized controlled trials and II for nonrandomized studies). In agreement with previous Ottawa Panel methods, Cochrane Collaboration methods were utilized for statistical analysis. Clinical significance was established by an improvement of ≥15% in the experimental group compared with the control group. There were a total of 79 recommendations from 9 articles. From these recommendations, there were 36 positive recommendations: 21 grade A and 15 grade C+. There were no grade B recommendations, and all recommendations were of clinical benefit. Limitations Further research is needed, as more than half of the trials were of low methodological quality. Conclusions This review suggests that physical activity and diet programs are beneficial, specifically for pain relief (9 grade A recommendations) and improved functional status (6 grade A and 7 grade C+ recommendations), for adults with OA who are obese or overweight. The Ottawa Panel was able to demonstrate that when comparing physical activity alone, diet alone, physical activity combined with diet, and control groups, the intervention including physical activity and diet produced the most beneficial results.

Changes in muscle strength, endurance, and reaction of the lower extremities with Tai Chi intervention

This study examines the effects of a 16-week Tai Chi (TC) training program on the muscle strength, endurance, and reaction time of the lower extremities of elderly people. A total of 40 elderly individuals (aged 60 years) completed the study. They were divided into two groups: the TC group (11 men and 11 women) underwent a supervised TC exercise program for 16 weeks, while the control group (9 men and 9 women) received general education for a comparable time period. Pre- and post-intervention measurements were conducted. An isokinetic dynamometer was used to measure the maximum concentric strength and dynamic endurance of the knee flexors and the extensors, and the maximum concentric strength of the ankle plantarflexors and dorsiflexors. The neuromuscular response of the rectus femoris, semitendinosus, gastrocnemius, and anterior tibialis muscles was measured by the onset latency to sudden perturbations using an electromyography system. After 16 weeks, the TC group showed a 19.9% increase in muscle strength of the knee flexors (p<.000) that was significantly greater than that in the control group (p=.046). There was also a significant decrease in semitendinosus muscle latency (6.6%, p=.014) that was significantly shorter than that in the control group (p=.042). No significant training effects were found in other measures. These results suggest that improving biomechanical characteristics of lower extremity muscles may need longer TC intervention for elderly people.

Comparison of plantar loads during treadmill and overground running

OBJECTIVES The objective of this study is to compare plantar loads during treadmill running and running on concrete and grass surfaces. DESIGN Crossover study design was used in the study. METHODS A total of 16 experienced heel-to-toe runners participated in the study. Plantar loads data were collected using a Novel Pedar insole sensor system during running on the treadmill, concrete, and grass surfaces at 3.8m/s running speed and then analyzed. RESULTS Compared with running on the two other surfaces, treadmill running showed a lower magnitude of maximum plantar pressure and maximum plantar force for the total foot, maximum plantar pressure at two toe regions, and maximum plantar force for the medial forefoot region and two toe regions (p<0.0017). Treadmill running also showed a longer absolute contact time at two toe regions compared with running on the other two surfaces (p<0.0017). CONCLUSIONS Treadmill running is associated with a lower magnitude of maximum plantar pressure and a lower maximum plantar force at the plantar areas. These results suggest that the plantar load distribution in treadmill running is not the same as the plantar load distribution in running on overground surfaces. Treadmill running may be useful in early rehabilitation programs. Patients with injuries in their lower extremities may benefit from the reduction in plantar loads. However, the translation to overground running needs investigation.

Cushioning and lateral stability functions of cloth sport shoes

In this study, we evaluated the protective functions of cloth sport shoes, including cushioning and lateral stability. Twelve male students participated in the study (mean ± s: age 12.7 ± 0.4 years, mass 40.7 ± 5.9 kg, height 1.50 ± 0.04 m). Cloth sport shoes, running shoes, basketball shoes, cross-training shoes, and barefoot conditions were investigated in random sequence. Human pendulum and cutting movement tests were used to assess cushioning performance and lateral stability, respectively. For cushioning, the running shoes (2.06 body weight, BW) performed the best, while the cross-training shoes (2.30 BW) and the basketball shoes (2.37 BW) both performed better than the cloth sport shoes (2.55 BW) and going barefoot (2.63 BW). For the lateral stability test, range of inversion–eversion was found to be from 3.6 to 4.9°, which was far less than that for adult participants (> 20°). No significant differences were found between conditions. All conditions showed prolonged durations from foot-strike to maximum inversion (66–95 ms), which was less vigorous than that for adult participants ( < 40 ms) and was unlikely to evoke intrinsic stability failure. In conclusion, the cloth sport shoe showed inferior cushioning capability but the same lateral stability as the other sports shoes for children.

Comparison of Plantar Loads During Running on Different Overground Surfaces

The objective of this study is to compare plantar loads during running on different overground surfaces. Fifteen heel-to-toe runners participated in the study. Plantar load data were collected and analyzed using an insole sensor system during running on concrete, synthetic rubber, and grass surfaces at a running speed of 3.8 m/s. Compared with running on concrete surface, running on natural grass showed a lower magnitude of maximum plantar pressure at the total foot (451.8kPa vs. 401.7kPa, p = 0.016), lateral midfoot (175.3kPa vs. 148.0kPa, p = 0.004), central forefoot (366.3kPa vs. 336.8kPa, p = 0.003), and lateral forefoot (290.2kPa vs. 257.9kPa, p = 0.004). Moreover, running on natural grass showed a longer relative contact time compared with running on a concrete surface at the central forefoot (81.9% vs. 78.8%, p = 0.017) and lateral forefoot (75.2% vs. 73.1%, p = 0.007). No significant difference was observed in other multiple comparisons. Different surfaces affected the plantar loads while running. The differences may help us to understand potential injury mechanisms.

The effect of school bag design and load on spinal posture during stair use by children

Thirteen male children ascending and descending stairs with loads that equalled 0%, 10%, 15% and 20% of their body weight were the subject of our research: the boys were wearing an asymmetrical single-strap athletic bag or a symmetrical double-strap backpack during our experiments with them. The maximum spinal tilt to the loading side and to the support side, and the range of spinal motions, were obtained by using a motion analysis system. Our results showed that symmetry of spinal posture was observed both when they ascended staircase with all loads and descended in a backpack. When carrying an athletic bag with 15% and 20% of their body weight while ascending the staircase, the lateral spinal tilt to the supporting side was significantly increased. We concluded that a symmetrical backpack with a load not exceeding 20% or an asymmetrical single-strap athletic bag with a load not exceeding 10% should be recommended for school children in order to promote safer staircase use. Statement of Relevance: Children carrying heavy school bags may develop spinal problems. This study suggested that when they are using stairs, a symmetrical backpack with a load within 20% body weight is acceptable for them. When they are carrying an asymmetrical single-strap athletic bag, the bags weight should not exceed 10% of the body weight in order to avoid excessive spinal tilt.

Proprioception of foot and ankle complex in young regular practitioners of ice hockey, ballet dancing and running.

This study examined the proprioception of the foot and ankle complex in regular ice hockey practitioners, runners, and ballet dancers. A total of 45 young people with different exercise habits formed four groups: the ice hockey, ballet dancing, running, and sedentary groups. Kinesthesia of the foot and ankle complex was measured in plantarflexion (PF), dorsiflexion (DF), inversion (IV), and eversion (EV) at 0.4°/s using a custom-made device. The results showed the following: (1) significantly better perceived passive motion sense in PF/DF was found as compared with the measurements in IV/EV within each group (P < .01); (2) ice hockey and ballet groups perceived significantly better passive motion sense in IV/EV than the running (P < .05) and the sedentary (P < .01) groups; and (3) no significant difference in the all measurements was found between running and sedentary groups. The benefits of ice hockey and ballet dancing on proprioception may be associated with their movement characteristics.

The Temporospatial and Kinematic Characteristics of Typical Tai Chi Movements: Repulse Monkey and Wave-hand in Cloud

Tai Chi movements share many similar biomechanical features with normal walking. The purpose of the study was to examine and to compare the temporospatial and kinematic features of two typical Tai Chi movements with forward walking. Experienced male Tai Chi practitioners (n = 15) between the ages of 65 to 75, performed ‘Repulse Monkey (RM)’, ‘Wave-hand in Cloud (WHIC)’, and forward walking. The results showed that stride width was larger for WHIC compared with walking; double-support time was longer for RM while both Tai Chi movements spent less time in single-support. The Tai Chi movements elicit larger vertical and mediolateral displacement of the centre of mass compared with walking. During RM and WHIC, the knees remained flexed while RM had notably larger abduction and adduction of the knee joint. The gentle and fluid Tai Chi movements have unique biomechanical features that may result in special training to postural control capacity.

Changes in heel cushioning characteristics of running shoes with running mileage

This study aims to investigate the changes in the cushioning characteristics of running shoes, particularly those with ethylene vinyl acetate (EVA) as midsole material, with mileage. Fifteen amateur runners participated in the study. Each participant ran for 500 km wearing a pair of these types of shoes. The cushioning characteristics of the shoes, specifically peak force and energy return, were measured before and after every 50 km running. The cushioning characteristics of running shoes changed with increasing mileage. On average, there was a 4.88% (95% CI = 3.40–6.36%) increase in peak force after 500 km of running. The results were inconsistent with those reported based on machine-simulated running studies, which overevaluated the cushioning deterioration of running shoes.

Gender differences in foot shape: a study of Chinese young adults

One important extrinsic factor that causes foot deformity and pain in women is footwear. Womens sports shoes are designed as smaller versions of mens shoes. Based on this, the current study aims to identify foot shape in 1,236 Chinese young adult men and 1,085 Chinese young adult women. Three-dimensional foot shape data were collected through video filming. Nineteen foot shape variables were measured, including girth (4 variables), length (4 variables), width (3 variables), height (7 variables), and angle (1 variable). A comparison of foot measures within the range of the common foot length (FL) categories indicates that women showed significantly smaller values of foot measures in width, height, and girth than men. Three foot types were classified, and distributions of different foot shapes within the same FL were found between women and men. Foot width, medial ball length, ball angle, and instep height showed significant differences among foot types in the same FL for both genders. There were differences in the foot shape between Chinese young women and men, which should be considered in the design of Chinese young adults’ sports shoes.