instruction:
In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
question:
Context: Old compared with young adults walk with reduced ankle and increased hip mechanical output. We examined the idea that age, leg strength, or both are related to the age-related changes in mechanical output during gait.', 'Healthy young (n = 32, age 21.5 years) and old adults (n = 32, age 76.8 years) participated in biomechanical gait analyses at 1.5 m/s and were also measured for maximal leg strength.', 'Analysis 1 confirmed previous data as old compared with young adults walked with 50 % more hip positive work and 18 % less ankle positive work. Analysis 2 showed that leg strength did not affect gait kinetics in groups of subjects with similar ages. In a weak young and a strong old group, Analysis 3 showed that old adults still walked with 23 % greater hip positive work. The group by joint interaction in Analysis 4 was suggestive of an even greater reliance on hip and less reliance on ankle work in weak compared with strong old adults.\Question: Do age and muscle strength mediate the age-related biomechanical plasticity of gait?
answer:
Age and leg strength both contribute to the age-related changes in mechanical output during gait. Exercise prescription, normally targeting the knee extensors, should also involve ankle and hip muscles.

question:
Context: To assess plantarflexion moment and hip joint moment after-effects following walking on a split-belt treadmill in healthy individuals and individuals post-stroke.', 'Cross-sectional study.', 'Ten healthy individuals (mean age 57.6 years (standard deviation; SD 17.2)) and twenty individuals post-stroke (mean age 49.3 years (SD 13.2)).', 'Participants walked on an instrumented split-belt treadmill under 3 gait periods: i) baseline (tied-belt); ii) adaptation (split-belt); and iii) post-adaptation (tied-belt). Participants post-stroke performed the protocol with the paretic and nonparetic leg on the faster belt when belts were split. Kinematic data were recorded with the Optotrak system and ground reaction forces were collected via the instrumented split-belt treadmill.', 'In both groups, the fast plantarflexion moment was reduced and the slow plantarflexion moment was increased from mid-stance to toe-off in the post-adaptation period. Significant relationships were found between the plantarflexion moment and contralateral step length.\Question: Is plantarflexion moment a contributor to step length after-effect following walking on a split-belt treadmill in individuals with stroke and healthy individuals?
answer:
Split-belt treadmills could be useful for restoring step length symmetry in individuals post-stroke who present with a longer paretic step length because the use of this type of intervention increases paretic plantarflexion moments. This intervention might be less recommended for individuals post-stroke with a shorter paretic step length because it reduces the paretic plantarflexion moment.

question:
Context: Routine tuberculosis control services in Burundi.', 'To determine whether systematic restaining of sputum smears for acid-fast bacilli (AFB) prior to rechecking quality assessment is necessary.', 'Blinded rechecking of peripheral routine smears, including a second control of discordants, before and after restaining.', 'Without restaining, 10/825 (1.2%) negative, and 59/189 (31.2%) positive results were declared false. After restaining, there were 34 (4.1%) false negatives and 13 (6.9%) false positives, both highly significant changes. Before restaining, quantification of positive smears was usually considered too high, while after restaining 41 out of 42 positives were found to have too low readings.\Question: Is systematic restaining of sputum smears for quality control useful in Burundi?
answer:
Despite mild climatic conditions in Burundi, restaining all slides before rechecking revealed an unrecognised, widespread problem of false negatives, rather than false positives. This indicated the need for critical re-appraisal of the standard procedure using cold staining, rather than re-training, as would have been inferred from results without restaining. Systematic restaining of all slides prior to rechecking may be more widely needed in National Tuberculosis Programmes to cover all possible serious causes of error. Cold staining should be avoided in field programmes since its performance is easily affected by frequently encountered adverse factors.