Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
Med Sci Sports Exerc. 2013 May;45(5):914-9. doi: 10.1249/MSS.0b013e31827e47ac.
The relationships between demographic and anthropometric indices and older adults' quantity and quality of ambulatory activity are uncertain. We examined the relationship between accelerometer-determined steps per day (quantity) and peak 30-min cadence (quality; mean steps per minute recorded for the 30 highest, but not necessarily consecutive, minutes in a day) in community-dwelling older adults relative to sex, age, and body mass index (BMI).
Minute-by-minute accelerometer-determined step data for 5.8 ± 0.9 d were available for 100 women and 43 men (58-92 yr, BMI = 26.6 ± 4.2 kg·m). Sex-specific Spearman correlations compared steps per day with peak 30-min cadence and both to age and BMI. Partial correlations were computed controlling for 1) age, 2) BMI, 3) steps per day and age, or 4) steps per day and BMI. Significance was set at P < 0.05.
Participants averaged 5605 ± 2588 steps per day with a peak 30-min cadence of 63.6 ± 24.6 steps per minute (mean ± SD). Correlations between these two variables were r = 0.883 (women) and r = 0.820 (men). Steps per day and peak 30-min cadence were significantly correlated with age (r = -0.442 and r = -0.327, respectively) and BMI (r = -0.248 and r = -0.286, respectively) in women. For men, steps per day and peak 30-min cadence were only significantly related to age (r = -0.665 and r = -0.381, respectively). Controlling for steps per day weakened all relationships with peak 30-min cadence to a point of nonsignificance with one exception: the partial correlation of age with peak 30-min cadence was weakened but remained significant (r = 0.335) after controlling for steps per day and BMI in men.
The usefulness of peak 30-min cadence beyond steps per day is not apparent, at least in terms of sex, age, and BMI, and needs to be evaluated in larger and more diverse samples and against other parameters of interest, including those more theoretically linked to intensity of effort.
人口统计学和人体测量学指标与老年人活动的数量和质量之间的关系尚不确定。我们研究了计步器确定的每日步数（数量）与峰值 30 分钟步频（质量；一天中记录的最高但不一定连续的 30 分钟内的平均每分钟步数）与性别、年龄和体重指数（BMI）在社区居住的老年人中的关系。
100 名女性和 43 名男性（58-92 岁，BMI=26.6±4.2kg·m）的计步器确定的每分钟步速数据可用 5.8±0.9d。性别特异性 Spearman 相关比较了每日步数与峰值 30 分钟步频的关系，以及与年龄和 BMI 的关系。控制 1）年龄、2）BMI、3）每日步数和年龄或 4）每日步数和 BMI 后进行偏相关计算。显著性设为 P<0.05。
参与者平均每天行走 5605±2588 步，峰值 30 分钟步频为 63.6±24.6 步/分钟（平均值±标准差）。这两个变量之间的相关性 r=0.883（女性）和 r=0.820（男性）。在女性中，每日步数和峰值 30 分钟步频与年龄（r=-0.442 和 r=-0.327）和 BMI（r=-0.248 和 r=-0.286）显著相关。对于男性，每日步数和峰值 30 分钟步频仅与年龄（r=-0.665 和 r=-0.381）显著相关。控制每日步数后，除一个例外，所有与峰值 30 分钟步频的关系均减弱至无统计学意义：控制每日步数和 BMI 后，男性年龄与峰值 30 分钟步频的偏相关仍显著（r=0.335）。
至少从性别、年龄和 BMI 的角度来看，峰值 30 分钟步频的作用并不明显，需要在更大、更多样化的样本中，并针对其他感兴趣的参数（包括与努力强度理论上更相关的参数）进行评估。
