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The purposes of this investigation were first to determine the impact of 3 different creatine (Cr) loading procedures on skeletal muscle total Cr (TCr) accumulation and, second, to evaluate the effectiveness of 2 maintenance regimes on retaining intramuscular TCr stores, in the 6 weeks following a 5-day Cr loading program (20 g · day⁻¹). Eighteen physically active male subjects were divided into 3 equal groups and administered either: (a) Cr (4 X 5 g · day⁻¹ X 5 days), (b) Glucose+Cr (1 g · kg⁻¹ of body mass twice per day), or (c) Cr in conjunction with 60 min of daily muscular (repeated-sprint) exercise. Following the 5-day loading period, subjects were reassigned to 3 maintenance groups and ingested either 0 g · day⁻¹, 2 g · day⁻¹ or 5 g · day⁻¹ of Cr for a period of 6 weeks. Muscle biopsy samples (vastus lateralis) were taken pre- and post-loading as well as post-maintenance and analyzed for skeletal muscle ATP, phosphocreatine (PCr), Cr, and TCr concentrations. Twenty-four hour urine samples were collected for each of the loading days and last 2 maintenance days, and used to determine whole body Cr retention. Post-loading TCr stores were significantly (p < .05) increased in all treatment conditions. The Glucose+Cr condition produced a greater elevation (p < .05) in TCr concentrations (25%) than the Cr Only (16%) or Exercise+Cr (18%) groups. Following the maintenance period, muscle TCr stores were still similar to post-loading values for both the 2 g · day⁻¹ and 5 g · day⁻¹ conditions. Intramuscular TCr values for the 0 g · day⁻¹ condition were significantly lower than the other conditions after the 6-week period. Although not significantly different from pre-loading concentrations, muscle TCr for the 0 g · day⁻¹ group had not fully returned to baseline levels at 6 weeks post-loading. The data suggests that Glucose+Cr (but with a much smaller glucose intake than currently accepted) is potentially the most effective means of elevating TCr accumulation in human skeletal muscle. Furthermore, after 5 days of Cr loading, elevated muscle TCr concentrations can be maintained by the ingestion of small daily Cr doses (2-5 g) for a period of 6 weeks and that TCr concentrations may take longer than currently accepted to return to baseline values after such a Cr loading regime.

Despite the popularity of Zumba dancing, research is scarce about its impact on older adults. Meanwhile, the integration of cognitive tasks with physical exercises, also known as dual tasking, is an evolving strategy to facilitate activities for older adults. This study investigated the perceptions of persons aged ≥55 years on Zumba and its potential to be incorporated into a dual-task program. We conducted a descriptive–qualitative study involving 44 Filipino older adults. Using content analysis, four themes were identified: moving toward match or mismatch, balancing benefits with burdens, dual tasking as innovative yet potentially challenging, and overcoming barriers with enablers. Although Zumba was perceived as an inclusive and beneficial activity, individual and contextual limitations could hinder its suitability. Moreover, dual tasking in Zumba was considered an innovative approach, although challenges should be addressed to promote its feasibility. Several strategies could enable the design and implementation of age-appropriate Zumba and dual-tasking programs for older adults.

This study attempted to determine the relationship between creatine (Cr) accumulation in human skeletal muscle and erythrocytes following Cr supplementation. If a strong relationship exists, a blood test might provide a practical, less invasive alternative than muscle biopsy for evaluating cellular Cr accumulation. Eighteen active, but not well-trained males were supplemented with Cr (4 × 5g/d) for 5 d. Muscle biopsies (vastus lateralis) were obtained pre- and post-loading and analyzed for Cr, phosphocreatine (PCr), and total Cr (TCr) content. Venous blood was also drawn at these times to determine erythrocyte Cr concentrations. Muscle Cr, PCr, and TCr concentrations were elevated (P < 0.05) by 39.8%, 7.5%, and 20.1% respectively following supplementation. Erythrocyte Cr concentrations were also elevated (P < 0.01) following the loading period, although to a greater relative degree than tissue concentrations (129.6%). Pre- and post-loading erythrocyte Cr concentrations were poorly and nonsignificantly correlated with that observed in skeletal muscle. Further, loading-mediated increases in erythrocyte Cr concentrations were poorly correlated with elevations in muscle Cr (r = 0.07), PCr (r = 0.06) or TCr (r = 0.04) concentrations. Erythrocyte Cr concentrations can be augmented by 5 d of Cr supplementation, however, this elevation does not reflect that observed in skeletal muscle obtained by muscle biopsy. Consequently, erythrocyte response to Cr loading is not a reliable measure of skeletal muscle Cr/TCr accumulation.