The purpose of this investigation was to determine whether increases in internal (muscular) demand would be proportional to increases in the external demand during heel-raise exercise. Seven male (mean age 74.9 ± 4.8 years) and 9 female (mean age 74.4 ± 5.1 years) older adults performed both double-leg heel raises and single-leg heel raises under 3 loading conditions (no external resistance and +5% and +10% of each participant’s body weight). Kinematic and kinetic dependent variables were calculated using standard inverse-dynamics techniques. The results suggest that although the single-heel raise led to increases in peak net joint moments, power, and mechanical-energy expenditure (MEE), it did so at the expense of range of motion and angular velocity. In addition, increasing the external resistance by 5% of participants’ body weight did not elicit significant changes in either the power or the MEE of the ankle joint. These effects should be considered when prescribing these exercises to older adults.
Sean P. Flanagan, Joo-Eun Song, Man-Ying Wang, Gail A. Greendale, Stanley P. Azen and George J. Salem
Yoonkyung Song, Hyuk In Yang, Eun-Young Lee, Mi-Seong Yu, Min Jae Kang, Hyun Joo Kang, Wook Song, YeonSoo Kim, Hyon Park, Han Joo Lee, Sang-hoon Suh, John C. Spence and Justin Y. Jeon
South Korea’s 2016 Report Card on Physical Activity for Children and Youth is the first assessment of physical activity according to the indicators set by Active Healthy Kids Global Alliance.
National surveys were used as preferred sources of data. This was then supported by peer-reviewed papers and government reports identified by a systematic search of the literature written in English or Korean. A Research Working Group then graded indicators based on the collected evidence.
Each indicator was graded as follows: Overall Physical Activity, D-; Organized Sport and Physical Activity Participation, C-; Active Transport, C+; Sedentary Behavior, F; School, D; Government and Investment, C; Active Play, Physical Literacy, Family and Peers, and Community and Built Environment were graded INC (incomplete) due to lack of available evidence.
Though the final grades of key indicators for South Korean children and youth are not satisfactory, increasing interests and investments have been demonstrated at a national level. More evidence is required for comprehensive assessment on all indicators to better inform policy and practice. This should be accompanied by the use of consistent criteria to contribute to global efforts for active healthy kids.
George J. Salem, Sean P. Flanagan, Man-Ying Wang, Joo-Eun Song, Stanley P. Azen and Gail A. Greendale
Stepping activities when wearing a weighted vest may enhance physical function in older persons. Using 3 weighted-vest resistance dosages, this study characterized the lower-extremity joint biomechanics associated with stepping activities in elders. Twenty healthy community-dwelling older adults, ages 74.5 ± 4.5 yrs, performed 3 trials of forward step-up and lateral step-up exercises while wearing a weighted vest which added 0% body weight (BW), 5% BW, or 10% BW. They performed these activities on a force platform while instrumented for biomechanical analysis. Repeated-measures ANOVA was used to evaluate the differences in ankle, knee, and hip maximum joint angles, peak net joint moments, joint powers, and impulses among both steping activities and the 3 loading conditions. Findings indicated that the 5% BW vest increased the kinetic output associated with the exercise activities at all three lower-extremity joints. These increases ranged from 5.9% for peak hip power to 12.5% for knee extensor impulse. The application of an additional 5% BW resistance did not affect peak joint moments or powers, but it did increase the joint impulses by 4–11%. Comparisons between exercise activities, across the 3 loading conditions, indicated that forward stepping preferentially targeted the hip extensors while lateral stepping targeted the plantar flexors; both activities equally targeted the knee extensors. Weighted-vest loads of 5% and 10% BW substantially increased the mechanical demand on the knee extensors, hip extensors (forward stepping), and ankle plantar flexors (lateral stepping).