Relative Validity and Reliability of Isometric Lower Extremity Strength Assessment in Older Adults by Using a Handheld Dynamometer

Background: Handheld dynamometry (HHD) is a practical alternative to traditional testing of lower extremity strength. However, its reliability and validity across different populations and settings are not clear. Hypothesis: We hypothesize that HHD is a valid and reliable device to assess lower extremity strength in a population of older adults. Study Design: Cross-sectional/cohort. Level of Evidence: Level 3. Methods: This study included 258 older adults (≥65 years). Isometric knee extension and flexion force were measured by 1 examiner, using an HHD (n = 222), including 3 repetitions to calculate within-day intrarater reliability. These measurements were repeated by the examiner in a subgroup (n = 23) to analyze intrarater reliability over a test-retest period of on average 8 weeks. In addition, HHD force measures were performed by a second examiner (n = 29) to analyze interrater reliability. In another subgroup (n = 77), isometric knee extension and flexion torque were measured by 1 examiner using both the HHD and Biodex System 4 to assess relative validity. Results: HHD and Biodex measurements were highly correlated and showed excellent concurrent validity. HHD systematically overestimated torque as compared with Biodex by 8 N·m on average. Same-day intrarater intraclass correlation coefficients (ICCs) ranged from 0.97 to 0.98. Interrater reliability ICCs ranged from 0.83 to 0.95. Conclusion: HHD represents a reliable and valid alternative to Biodex to rank individuals on leg strength, or to assess within-person changes in leg strength over time, because of the high validity and reliability. The HHD is less suited for absolute strength assessment because of significant systematic overestimations. Clinical Relevance: Clinicians are encouraged to use HHD to rank older adults on leg strength, or to assess within-person changes in leg strength over time, but not to compare readings with cut-offs or normative values

Dose–response effects of supplementation with calcifediol on serum 25-hydroxyvitamin D status and its metabolites: A randomized controlled trial in older adults

Dose–response effects of supplementation with calcifediol on serum 25-hydroxyvitamin D status and its metabolites: A randomized controlled trial in older adult

Cholecalciferol or 25-hydroxycholecalciferol supplementation does not affect muscle strength and physical performance in prefrail and frail older adults

Cholecalciferol or 25-hydroxycholecalciferol supplementation does not affect muscle strength and physical performance in prefrail and frail older adult

Vitamines – algemeen

Een adequate vitamine-inname is zeker niet vanzelfsprekend, en deficiënties door bijvoorbeeld ondervoeding, eenzijdige voeding, medicijngebruik of andere factoren blijven wereldwijd een probleem. Voor sommige vitamines is de optimale inname of concentratie nog steeds onderwerp van discussie. In dit hoofdstuk ligt de nadruk op de fysiologische aspecten van vitamines, hun opname en effecten in het lichaam. Het is vooral gericht op de diëtist die zich wil verdiepen in de basisprincipes, achtergronden en recente ontwikkelingen rond vitamines. Dertien voor de mens relevante vitamines komen één voor één aan de orde, daarbij aantekenend dat het belang van hun onderlinge samenhang in de voedingsmatrix en het eetpatroon maakt dat we ze eigenlijk niet afzonderlijk zouden moeten bespreken. De laatste jaren is over sommige vitamines meer geschreven en gediscussieerd dan over andere. Voorbeelden zijn vitamine B6 (vooral in verband met overdosering), vitamine B12, vitamine C, vitamine D en vitamine K2. Deze ontwikkelingen krijgen in dit hoofdstuk daarom extra aandacht