Extracellular Water May Mask Actual Muscle Atrophy During Aging

Background.\nSkeletal muscle tissue holds a large volume of water partitioned into extracellular water (ECW) and intracellular water (ICW) fractions. As the ECW may not be related to muscle strength directly, we hypothesized that excluding ECW from muscle volume would strengthen the correlation with muscle strength.Methods.\nA total of 119 healthy men aged 20–88 years old participated in this study. Knee isometric extension strength, vertical jump, and standing from a chair were measured as indices of muscle strength and power in the lower extremities. The regional lean volume (LV), total water (TW), ICW, and ECW in the lower leg were estimated by anthropometry (skinfold and circumference measurements) and segmental multifrequency bioelectrical impedance spectroscopy (S-BIS). Then, we calculated the ECW/TW and ICW/TW ratios.Results.\nAlthough ICW and the LV index decreased significantly with age (p < .001), no significant changes in ECW were observed (p = .134). Consequently, the ECW/TW ratio increased significantly (p < .001) with age (young adult, 27.0 ± 2.9%; elderly, 34.3 ± 4.9%; advanced elderly, 37.2 ± 7.0%). Adjusting for this by including the ICW/TW ratio in our models significantly improved the correlation between the LV index and strength-related measurements and correlated with strength-related measurements independently of the LV index (p < .001).Conclusions.\nThe ECW/TW ratio increases in the lower leg with age. The results suggest that the expansion of ECW relative to ICW and the LV masked actual muscle cell atrophy with aging

Age- and sex-related differences of muscle cross-sectional area in iliocapsularis: a cross-sectional study

[Background] This study aimed to determine in how many individuals the iliocapsularis muscle (IC) could be identified on magnetic resonance imaging (MRI) and whether age and sex are associated with the cross-sectional area (CSA) of the IC. [Methods] Thirty-seven healthy younger adults and 40 healthy older adults were assigned to four groups: 1) 20 younger men; 2) 17 younger women; 3) 20 older men; and 4) 20 older women. The CSAs of the IC, IP, the rectus femoris (RF) and the quadriceps (QUAD) were quantified on an axial MRI. [Results] The number of individuals with the identified IC was n = 17 (85.0%) of 20 younger men, n = 15 (88.2%) of 17 younger women, n = 18 (90.0%) of 20 older men, and 19 (95.0%) of 20 older women. Our results showed the main effect of sex, but not age, in the CSA of the IC. The men-groups had larger CSA of the IC than the women-groups; however, no difference in CSA of the IC was found between the younger and older groups. Meanwhile, the main effects of age and sex were found for the IP, RF, and QUAD; thus, younger or men groups have larger CSAs of the three muscles than the older or women groups. The IC muscle can be discriminated in 85% – 95% of healthy individuals. [Conclusion] Although sex and age are associated with the CSA of lower-limb muscles other than the IC, only sex is associated with the CSA of the IC

亀岡市在住高齢者を対象にした前向きコホート研究（亀岡スタディ）10年の歩み

In Japan with rapid and serious aging of the population, prolongation of healthy lifespan by delaying the initiation of nursing care has become an important issue. The Kyoto-Kameoka Study is a large-scale prospective cohort study to evaluate whether preventive elderly care with a complex program consisting mainly of exercise but also incorporating diet/nutrition and oral care (frailty-prevention program) contributes to prolongation of healthy lifespan of the older population of an entire local community. The project is reviewed retrospectively 10 years after its initiation.As a result of intervention in about 500 residents, the exercise-centered complex frailtyprevention program was shown to lead to increases in physical activity and muscle mass, maintenance or improvement of physical ability, and control of progression of the care level and the nursing care benefit expense. In addition, a system to propagate frailty prevention activities in a variety of forms to the community was prepared with the continuation of frailty prevention supporter training seminars by an incorporated NPO established to sponsor and organize them.長寿・超高齢化の進行するわが国では，介護の先送りによる健康寿命の延伸が重要な課題となっている。亀岡スタディは，運動を中心に，食事・栄養，口腔ケアからなる複合型プログラムによる介護予防（フレイル対策）が，地域全体の高齢者の健康寿命延伸に寄与できるかを検証するための大規模な前向きコホート研究である。プロジェクト開始から10 年を迎え，この間の歩みを振り返ってみた。約500 名を対象にした介入の結果，運動を中心にした複合型介護予防プログラムは，身体活動量の増加や筋量・体力の向上・維持につながり，要介護認定や介護給付費を抑制することが明らかになった。また，介護予防サポーター養成講座の継続と，その受け皿として設立したNPO 法人により，様々な形での介護予防活動を地域に展開する仕組みが整いつつある。研究活動報

Association of Pain History and Current Pain With Sagittal Spinal Alignment and Muscle Stiffness and Muscle Mass of the Back Muscles in Middle-aged and Elderly Women

[Study Design] A cross-sectional study. [Objective] To investigate the association of low back pain history (LBPH) and LBP with sagittal spinal alignment, stiffness assessed using ultrasonic shear wave elastography, and mass of the back muscle in community-dwelling middle-aged and elderly women. [Summary of Background Data] The association of LBPH and LBP with sagittal spinal alignment, stiffness, and mass of the back muscles remains unclear in middle-aged and elderly women. [Participants and Methods] The study comprised 19 asymptomatic middle-aged and elderly women [control (CTR) group], 16 middle-aged and elderly women with LBPH (LBPH group), and 23 middle-aged and elderly women with LBP (LBP group). Sagittal spinal alignment in the standing and prone positions (kyphosis angle in the thoracic spine, lordosis angle in the lumbar spine, and anterior inclination angle in the sacrum) was measured using a Spinal Mouse. The stiffness of the back muscles (lumbar erector spinae and multifidus) in the prone position was measured using ultrasonic shear wave elastography. The mass of the back muscles (thoracic and lumbar erector spinae, lumbar multifidus, and quadratus lumborum) was also measured. [Results] Multiple logistic regression analysis with a forward selection method showed that the stiffness of the lumbar multifidus muscle was a significant and independent factor of LBPH. The stiffness of the lumbar multifidus muscle was significantly higher in the LBPH group than in the CTR group. Multiple logistic regression analysis also indicated that lumbar lordosis angle in the standing position was a significant and independent factor of LBP. The lumbar lordosis angle was significantly smaller in the LBP group than in the CTR group. [Conclusions] Our results suggest that LBPH is associated with increased stiffness of the lumbar multifidus muscle in the prone position, and that LBP is associated with the decreased lumbar lordosis in the standing position in community-dwelling middle-aged and elderly women

中高齢者のバランス調整能の評価手法の開発 （ファンクショナル・リーチテストの課題）

目的：中高齢者の体力要素や運動能力のひとつである姿勢保持能力の低下や転倒の要因を探る手掛かりを得るため、これまで著者らが実施してきた開眼・閉眼片足立ちや重心動揺の測定と同時に3種類のファンクショナル・リーチ（FR）テストを行い、特に動的バランス調整能の指標としての3種類のFRテストの信頼性と有効性について検討した。方法：60～89歳の男女242名（男性72名，女性170名）を対象に、体格、体力診断バッテリーテスト（開眼・閉眼片足立ち、座位ステッピング、長座位体前屈、箱押し体前屈、垂直跳び、握力、シャトルスタミナウォークテスト、チェアスタンド）、3種類のFRテスト（片手FR・両手FR・重心移動FR）の測定及び重心動揺計による重心位置の前方向への移動（A-C％）、重心位置の後方への移動（C-P％）を測定し、A-C％とC-P％の合計値、すなわち身体の支持基盤の大きさ（A-P％）を算出した。結果：A-P％と重心移動FRテストとの間には、男性r＝0.603、女性r＝0.628の高い相関が認められた。片手FRテストと両手FRテストの問にも、男性r＝0.786、女性r＝0.757の高い相関が認められた。開眼片足立ちと片手FRテストとの相関係数は、男性のA-P％や重心移動FRテストと女性の重心移動FRテストの値より高く、両手FRテストとの相関係数は、男女共にA-P％や重心移動FRテストの値より高かった。結論：片手及び両手FRテストは下肢筋力の影響を反影する測定であり、中高齢者においては重心移動FRテストよりも実施上の問題が少なく、汎用性の高い有用な方法となる可能性がある

中高齢者の動的バランス能について （ファンクショナル・リーチテストの検討）

目的：中高齢者の姿勢保持能力低下と転倒の要因を探るため、開眼・閉眼片足立ち、重心動揺の測定、ファンクショナル・リーチテスト（FR）を行い、FRの信頼性と精度を検証するとともに、体力要素や運動能力との関連について検討した。方法：60～87歳の男女68名（男性27名、女性41名）を対象に、体力診断バッテリーテスト（開眼・閉眼片足立ち、座位ステッピング、長座位体前屈、垂直跳び、握力、シャトルスタミナウォークテスト）、重心動揺計による測定、FRおよびFR両手法を行った。結果：片足立ちテストとFRの成績は、体力要素と同様に加齢に応じて有意に減少するが、女性における年齢群間差は認められなかった。FR両手法の成績は、女性の年齢群間のみに有意差がみられた。重心動揺の成績については、加齢による変化はみられなかった。FRとFR両手法において、男性はFR両手法のステッピングを除くすべての体力要素に有意な相関を認め、女性はFRと握力との間に有意な相関を認めただけで、他の体力要素との関連はなかった。FRとFR両手法の間には有意な相関を認め（男性r=0.622、女性r=0.522）、年齢で制御しても有意な相関を認めた（男性r＝0.602、女性r＝0.486）。FRと平衡機能の指標において、男性では開眼片足立ち、A-C％、C-P％、A-P％との間に、女性では開眼での重心動揺軌跡長、C-P％、A-P％との間に有意な相関を示し、最も高い相関を示したのは、男性のA-P％で、r＝0.704を認め、女性でもr＝0.394であったが、FR両手法においては、男性では有意な相関を示さず、女性では重心動揺軌跡長、C-P％、A-P％との間に有意な相関を示した。結論:FRの信頼性と精度については、FRによる測定は動的な平衡性の要素が大きいことが考えられ、FR両手法は筋力の低い女性や虚弱な高齢者に応用できる容易で簡便な方法となる可能性がある

中高齢女性の下肢筋力と平衡性との関連

目的：転倒予防策を体力面から探るため、中高齢女性におけるバランス調整力を含む体力要素と下肢筋力である膝関節の伸展力（膝伸展力）、足関節の底屈力と背屈力（足底屈力、足背屈力）との相互関連を検討した。方法：40～89歳の女性285名を対象に、片足立ちテストと重心動揺計による平衡能の測定、下肢筋力（膝伸展力、足底屈力、足背屈力）の測定および体力診断バッテリーテスト（開眼・閉眼片足立ち、座位ステッピング、長座位体前屈、垂直跳び、握力、シャトルスタミナウォークテスト）の測定を行った。結果：被験者の体力値および片足立ちテストの成績は加齢による有意な低下を示した。重心動揺計による成績は重心位置の割合（G％）を除いた全ての項目において有意な加齢変化が認められた。膝伸展力、足底屈力は直線的な加齢低下を示し、50歳群より有意な差を認めたが、足背屈力は40歳群から60歳群まで加齢変化を認めず、70歳以降から有意に低下し始めた。下肢筋力と体力診断バッテリーテストとの間には有意な関連が認められ、特に垂直跳びは膝伸展力、足底屈力との間に0.6以上の高い相関を示した。片足立ちテストと重心動揺の各パラメータは下肢筋力、特に膝伸展力と足底屈力との間では全て有意な相関を示し、特に開眼片足立ちでは0.419～0.515、次いで最大前傾位と最大後傾位での重心位置の間隔（A-P％）では0.356～0.393の有意な相関が認められた。結論：転倒予防には、平衡能を確保する上で、筋力、特に下肢筋力の維持あるいは向上が極めて重要であることが示唆された

Relation between walking fluctuation and physical fitness in the middle-aged and elderly

This study examined the relationship between walking fluctuation and physical fitness in 21 middle-aged and elderly healthy women (65.95 ± 6.6 years). Walking data was gained during a typical six-minute walk by using sensors in the participantsʼ shoes. Stride time (ST), the coefficient of variation of stride time (STCV), and the fractal-scaling index (α) were calculated. Also measured were the ten-meter usual walking time, functional reach, one-leg standing time with eyes open, vertical jump height, and grip strength, and a fitness age score (FAS) was then calculated by using these results. In addition, twenty-second stepping frequency, thirty-second chair standing frequency, and isometric knee extension strength were measured. There was a significant negative correlation between age and FAS (r=-0.590, p=0.005). When participants were divided into two groups by a median of ST, STCV and α, significantly superior physical fitness were observed in higher ST and higher STCV groups, whereas significantly longer step length were observed in higher α groups.This study therefore suggests that STCV is more affected by musculoskeletal function than α.論

Constructing an index of physical fitness age for Japanese elderly based on 7-year longitudinal data: sex differences in estimated physical fitness age

A standardized method for assessing the physical fitness of elderly adults has not yet been established. In this study, we developed an index of physical fitness age (fitness age score, FAS) for older Japanese adults and investigated sex differences based on the estimated FAS. Healthy elderly adults (52 men, 70 women) who underwent physical fitness tests once yearly for 7 years between 2002 and 2008 were included in this study. The age of the participants at the beginning of this study ranged from 60.0 to 83.0 years. The physical fitness tests consisted of 13 items to measure balance, agility, flexibility, muscle strength, and endurance. Three criteria were used to evaluate fitness markers of aging: (1) significant cross-sectional correlation with age; (2) significant longitudinal change with age consistent with the cross-sectional correlation; and (3) significant stability of individual differences. We developed an equation to assess individual FAS values using the first principal component derived from principal component analysis. Five candidate fitness markers of aging (10-m walking time, functional reach, one leg stand with eyes open, vertical jump and grip strength) were selected from the 13 physical fitness tests. Individual FAS was predicted from these five fitness markers using a principal component model. Individual FAS showed high longitudinal stability for age-related changes. This investigation of the longitudinal changes of individual FAS revealed that women had relatively lower physical fitness compared with men, but their rate of physical fitness aging was slower than that of men