Associations of Morphological Changes in Skeletal Muscles of Preschool Children in China Following Physical Activity.

PURPOSE: Physical activity (PA) is likely to be the most important modifiable factor in skeletal muscle development. However, the influence of PA on the skeletal muscle of preschool children has not been thoroughly investigated. The main objective of this study was to quantitatively measure PA, and then, to assess whether associations exist between site-specific muscle changes and PA in relation to sex and weight statuses in preschool children aged 3 to 4 years. METHODS: A total of 86 healthy preschool children, aged 3-4 years, were instructed to wear an accelerometer for seven consecutive days. The number of steps taken daily, and minutes spent in moderate-vigorous PA (MVPA) and total PA (TPA) were recorded. Muscle thickness was measured by B-mode ultrasonography using a 5-18 MHz scanning head. Muscle thickness was measured at seven sites: the lateral forearm, upper arm, abdomen, anterior and posterior thigh, and anterior and posterior lower leg. RESULTS: There was no significant difference between boys and girls in terms of MVPA and TPA on weekdays and weekends. According to the linear regression models, after adjusting for daylight duration, the muscle of the posterior thigh was significantly positively associated (p < 0.05) with daily steps and MVPA on weekdays for boys and girls, respectively. CONCLUSIONS: We found that the muscle thickness of the posterior thigh in preschool children was significantly positively associated with PA, as measured by daily steps and MVPA. We suggest that for the overall health and well-being of preschool children, the levels of PA should be maintained and/or increased, and preferably transformed into a regular part of daily living.

Correction: Ishihara et al. Association between Daily Physical Activity and Locomotive Syndrome in Community-Dwelling Japanese Older Adults: A Cross-Sectional Study. Int. J. Environ. Res. Public Health 2022, 19, 8164.

There was an error in the "d-value of the first paragraph in Section 3 (Results)" in the original publication (Page 5, Line 41) [...].

Longitudinal changes of grip strength and forearm muscle thickness in young children.

Background: Grip strength is a marker of future health conditions and is mainly generated by the extrinsic flexor muscles of the fingers. Therefore, whether or not there is a relationship between grip strength and forearm muscle size is vital in considering strategies for grip strength development during growth. Thus, this study aimed to examine the association between changes in grip strength and forearm muscle thickness in young children. Methods: Two hundred eighteen young children (104 boys and 114 girls) performed maximum voluntary grip strength and ultrasound-measured muscle thickness measurements in the right hand. Two muscle thicknesses were measured as the perpendicular distance between the adipose tissue-muscle interface and muscle-bone interface of the radius (MT-radius) and ulna (MT-ulna). All participants completed the first measurement and underwent a second measurement one year after the first one. Results: There were significant (P < 0.001) within-subject correlations between MT-ulna and grip strength [r = 0.50 (0.40, 0.60)] and MT-radius and grip strength [r = 0.59 (0.49, 0.67)]. There was no significant between-subject correlation between MT-ulna and grip strength [r = 0.07 (-0.05, 0.20)], but there was a statistically significant (P < 0.001) between-subject relationship between MT-radius and grip strength [r = 0.27 (0.14, 0.39)]. Conclusion: Although we cannot infer causation from the present study, our findings suggest that as muscle size increases within a child, so does muscle strength. Our between-subject analysis, however, suggests that those who observed the greatest change in muscle size did not necessarily get the strongest.

Relationship between Skeletal Muscle Thickness and Physical Activity in 4- to 6-Year-Olds in Japan.

PURPOSE: Physical activity (PA) is widely recognized as a key factor in promoting skeletal muscle growth, though little is known about the specific impact of PA on the skeletal muscle development of preschool children. The purpose of this study is to investigate whether there is a relationship between PA levels and skeletal muscle thickness in preschoolers. By exploring this relationship, we hope to gain a better understanding of how PA can be used to promote healthy skeletal muscle development in preschoolers. METHODS: In this study, a total of 275 healthy Japanese preschoolers, aged 4-6 years, from seven nursery schools in the town of Togo were recruited. Participants were asked to wear an accelerometer for four consecutive days to record their daily steps and the amount of time spent in moderate-to-vigorous PA and t total physical activity. Muscle thickness (MTs) was measured using B-mode ultrasonography at four sites: the anterior and posterior thigh (AT and PT, respectively) and the anterior and posterior lower leg (AL and PL, respectively). RESULTS: On weekdays, boys were found to be more physically active and engaged in significantly higher levels of total physical activity and moderate-to-vigorous PA than girls. Both boys and girls recorded more physical activity, daily steps, and higher levels of total physical activity and MVPA on weekdays compared to weekends. After adjusting for daylight duration, multivariable regression analyses revealed that increased total physical activity and moderate-to-vigorous PA were positively associated with greater muscle thickness size in the anterior tibialis (AT) and posterior lower leg (PL) muscles (ß = 1.11 and ß = 1.37 for AT, ß = 1.18 and ß = 0.94 for PL, p < 0.05) in Japanese preschoolers. CONCLUSIONS: The time spent involved in most of the different categories of moderate-to-vigorous PA was significantly higher for boys than for girls on the weekdays and weekends. Additionally, there was a positive correlation between time spent in moderate-to-vigorous PA and greater development of skeletal muscle in the lower body.

Effect of Isokinetic Training with Blood Flow Restriction During Rest Interval Versus Exercise on Muscle Strength, Hypertrophy, and Perception: A Pilot Study.

Objectives: This study aimed to determine the effects of high-intensity isokinetic training with blood flow restriction during rest interval between set (rBFR) versus during exercise (eBFR) on muscle hypertrophy and increasing muscle strength and determine whether BFR-induced exercise pain is suppressed by rBFR. Materials and Methods: Fourteen arms (7 participants) were recruited for the study. We conducted the following interventions for each arm: eBFR (n=4), rBFR (n=5), and exercise only (CON, n=5). The participants performed elbow flexion training with a BIODEX device twice weekly for 8 weeks. This study training consisted of total four sets; each was performed until <50% peak torque was achieved twice consecutively. BFR pressure was set at 120 mmHg. Elbow flexor peak torque during concentric contraction (CC), isometric contraction (IM), and muscle cross-sectional area (CSA) were measured before and after the intervention. Numerical rating scale scores used to assess pain during exercise were determined during training. Results: Peak torque at the CC increased in the rBFR (p<0.05) and IM increased in the rBFR and CON (p<0.05), while CSA increased in the rBFR and CON (p<0.001). The pain during exercise was severe in the eBFR and moderate in the rBFR and CON. Conclusions: This study's showed that high-intensity isokinetic training with rBFR did not have a synergistic effect on increasing muscle strength and muscle size. Additionally, high-intensity isokinetic training with BFR when it may be best not to perform it during exercise, because it was induces severe pain and may inhibit increases in muscle strength.

Children with Low Handgrip Strength: A Narrative Review of Possible Exercise Strategies to Improve Its Development.

BACKGROUND: Handgrip strength (HGS) is a predictor of health in both children and adults. Evidence suggests that without a possible strategy, children with low HGS may become adults with low HGS. However, little is known about what strategies are effective for children with low HGS to achieve a higher baseline level in adulthood. This narrative review aimed to investigate whether physical exercise interventions could improve HGS in children. METHODS: The relevant databases/search engine was searched using keywords related to the main topics discussed throughout this review. RESULTS: Our findings suggest that it may not be possible to improve HGS over that observed from normal development with physical education or traditional resistance-training programs. However, if the training program includes exercises that directly stimulate the forearm/hand muscle groups to grip, it may be possible to obtain changes in HGS that exceed the changes due to normal developmental growth. CONCLUSION: Although there are associations between HGS and markers of health, no research could be identified that examined whether increasing HGS would lead to an improvement in health. If an increase in HGS really does represent an improvement in long-term health, then gripping exercise may need to be included into physical activity programs during the growth/development phase.

Association between Daily Physical Activity and Locomotive Syndrome in Community-Dwelling Japanese Older Adults: A Cross-Sectional Study.

This study aimed to evaluate the association between locomotive syndrome (LS) and daily physical activity (PA) in community-dwelling older adults. This cross-sectional study included 80 healthy Japanese older adults (40 men and 40 women; age: 60-79 years). Habitual daily PA was evaluated using a triaxial wrist accelerometer. Participants were divided into two groups based on the results of the two-step test, stand-up test, and 25-question geriatric locomotive function scale. Binomial logistic regression analysis was conducted to examine the statistical relationships between daily PA and category of LS, adjusting for age from adjusted odds ratio (adjusted OR) with the 95 percent confidence intervals (95%CI) and bootstrap 95%CI. The mean step count and time spent on moderate to vigorous physical activity (MVPA) were significantly higher among non-LS participants than among LS participants in women, but not in men. Logistic regression analyses indicated that spending longer than 28 min/day on MVPA was significantly associated with a lower likelihood of LS relative to short time category under 28 min/day in women (adjusted OR = 0.12, 95%CI = 0.02-0.59, bootstrap 95%CI = 0.01-0.43), but not in men. This study suggests that in community-dwelling older women, those with higher MVPA had lower odds of LS, and daily MVPA was associated with LS, but not in men. Therefore, the associations between LS and daily physical activity were partly dependent on sex differences.

Effect of low-intensity exercise with blood flow restriction during rest intervals on muscle function and perception.

PURPOSE: We assessed the effects of low-intensity exercise with blood flow restriction (BFR) during rest intervals on recovery of muscle function and pain during exercise and rest intervals. METHODS: Participants were 10 males and study arms of the participants were randomly assigned into three conditions; low-intensity exercise with BFR during rest intervals (rBFR), low-intensity exercise with BFR during exercise (eBFR) and low-intensity exercise only (EO). The exercise task was elbow flexion until repetition failure at 30% of 1 RM and cuff pressure was 120 mmHg. The maximum voluntary isometric contraction (MVIC) and the muscle endurance (ME) were measured pre, post, 1, 24 and 48 h after the exercise. Pain during exercise and rest intervals were evaluated using the Numerical Rating Scale. RESULTS: MVIC and ME significantly decreased after exercise in all conditions. Pain during exercise was lower in rBFR (4.2 ± 2.9) (p = 0.007) and EO (4.4 ± 2.7) (p = 0.014) conditions compared to eBFR condition (6.7 ± 1.7), but the pain during rest intervals was more intense in rBFR condition (5.2 ± 1.6) compared to eBFR (1.5 ± 1.4) and EO (1.7 ± 1.2) conditions (p < 0.001). CONCLUSION: We discovered that recovery of muscle function was the same as BFR during rest intervals and BFR during exercise. Also, our results suggested that BFR itself may cause the perception of pain. Future studies are thus required to investigate the optimal dosage focusing on the pressure volume and intensity used in BFR during intervals.

A longitudinal study of handgrip strength asymmetry.

OBJECTIVE: The previous results from cross-sectional studies indicate that there could be alterations across time in handgrip strength (HGS) asymmetry. One way to investigate this is to test the same children multiple times. Therefore, we aimed to evaluate the laterality of HGS in healthy young children at two different time points separated by a year. METHODS: A total of 165 preschool children (79 males and 87 females) between the ages of 4.5 and 5.6 years participated and performed maximal voluntary HGS in both hands using a Smedley handgrip dynamometer. We ran a paired sample t-test on the difference scores (right - left vs. right - left) to determine if HGS (right vs. left) differed across time. RESULTS: The difference between hands (t = -4.804, p < .0001) did differ between time points. At the initial test, the mean value of the HGS in the right hand was approximately 15% higher than that of the left hand. This difference between hands was reduced following a year. The mean bias between tests (second test - initial test) and the 95% limits of agreement was -0.84 (-5.27, 3.58) kg. CONCLUSION: Contrary to our hypothesis, HGS asymmetry during the initial test (at age 5) was not observed in the second test completed a year later (at age 6). These results suggest that HGS asymmetry is uncertain in children between 5 and 6 years. In this short-term study, it was impossible to ascertain when HGS asymmetry first appeared. Longer term studies are required to better determine when these changes occur.

Effect of Gear Ratio and Cadence on Gross Efficiency and Pedal Force Effectiveness during Multistage Graded Cycling Test Using a Road Racing Bicycle.

Gross efficiency (GE) and the index of pedal force effectiveness (IFE) are important factors that enhance cyclists' performance; however, the effects of changing pedal force (gear ratio) and cadence on these indices while riding on a road racing bicycle are poorly investigated. This study aimed to examine the effect of changing gear ratio or cadence on GE and IFE using a road racing bicycle. Nine male cyclists completed graded submaximal cycling tests (five stages of 4 min submaximal cycling sessions with 1 min passive rest intervals). The work rate of each stage was determined using two principles: changing gear ratio at a fixed cadence and changing cadence at a fixed gear ratio. We determined GE and IFE using respiratory variables and pedal reaction forces, respectively. Increasing the gear ratio improved GE, and was associated with the IFE. Although increasing the cadence slightly improved GE from the initial level, the increased values then mostly maintained. IFE was almost stable even when cadence increased. Moreover, no significant correlation was observed between the changes in GE and IFE accompanied by increasing cadence. Our data indicate that an increasing gear ratio, but not cadence, may affect GE and IFE while riding on a road racing bicycle.

Serum albumin levels as a predictive biomarker for low-load resistance training programs' effects on muscle thickness in the community-dwelling elderly Japanese population: interventional study result.

BACKGROUND: Resistance training has been recommended as an effective measure against age-related loss of muscle mass and muscle strength, called sarcopenia, even in older adults. However, despite subjecting each participant to the same training program, the training effect solely depended on the individual. This study aimed to evaluate whether certain blood parameters influenced the effect of a low-load resistance training program on muscle thickness in the community-dwelling elderly population. METHODS: Sixty-nine community-dwelling Japanese (49 women and 20 men) subjects aged 69.4 ± 6.5 years were included. Low-load resistance training was performed twice a week for 12 weeks. Muscle thickness at the anterior aspects of the thigh (AT) was measured using a B-mode ultrasound device, and 22 blood parameter levels were assessed before and after the program. We checked the first quartile value of each parameter to establish cutoff values, and participants were divided into low or normal groups for each parameter. RESULTS: A low-load resistance training program significantly increased muscle thickness at the AT. The interaction between time and groups was examined at low (< 4.1 g/dL) versus normal (≥ 4.1 g/dL) serum albumin (Alb) levels. Although there was no difference in muscle thickness at the AT before the training intervention, the hypertrophic effects were higher in the normal serum Alb level group than in the low serum Alb level group. The binomial logistic regression analysis showed that participants in the low serum Alb group had an odds ratio of 7.08 for decreased muscle thickness at the AT. The effect of a low-load resistance training program on lower limb muscle thickness appears to be limited in participants with low serum Alb levels before training interventions. CONCLUSIONS: Serum Alb level may act as a biomarker to predict the effects of low-load resistance training programs on muscle hypertrophy in elderly individuals. TRIAL REGISTRATION: This study was retrospectively registered in UMIN-Clinical Trial Registry (CTR), ID: UMIN000042759 (date of registration, 14 Dec 2020).

The 30-s chair stand test can be a useful tool for screening sarcopenia in elderly Japanese participants.

BACKGROUND: Low muscle strength has been focused on as an essential characteristic of sarcopenia, and the 30-s chair stand test (CS-30) could be a particularly useful test for assessing muscle strength. While it is speculated to be a beneficial tool for the assessment of sarcopenia, this remains to be verified. In this study, we examined the reliability and optimal diagnostic score of the CS-30 for assessing sarcopenia in elderly Japanese participants. METHODS: This cross-sectional study included 678 participants (443 females and 235 males) who underwent the test for sarcopenia as per the Asian Working Group for Sarcopenia (AWGS) 2019, the CS-30 test, and the isometric knee-extension muscle strength test. ROC analysis was used to estimate the optimal CS-30 scores at which sarcopenia was detected. RESULTS: CS-30 scores were positively associated with sarcopenia (OR: 0.88; 95% CI:0.82-0.93). The AUC of the CS-30 for sarcopenia definition were 0.84 (p < 0.001) for females and 0.80 (p < 0.001) for males. The optimal number of stands in the CS-30 that predicted sarcopenia was 15 for females (sensitivity, 76.4%; specificity, 76.8%) and 17 for males (sensitivity, 75.0%; specificity, 71.7%). CONCLUSIONS: The CS-30 was found to be a reliable test for sarcopenia screening in the elderly Japanese population.

Site-Specific Muscle Loss in the Abdomen and Anterior Thigh in Elderly Males with Locomotive Syndrome.

Although locomotive syndrome (LS) is a condition of reduced mobility, little information is available regarding the loss of site-specific skeletal muscle mass. The aim of the present study is to examine site-specific muscle loss in elderly males with LS. A total of 100 men ranging in age from 65 to 74 years were divided into two groups (LS and non-LS) using LS risk tests including the stand-up test, two-step test, and the 25-question geriatric locomotive function scale Muscle thickness (MTH) at eight sites-anterior and posterior thigh (AT and PT, respectively), anterior and posterior lower leg (AL and PL, respectively), rectus abdominis (RA), anterior and posterior upper arm (AU and PU, respectively), and anterior forearm (AF)-was evaluated using B-mode ultrasound. Furthermore, the 30-s chair stand test (CS-30), 10-m walking time, zig-zag walking time, and sit-up test were assessed as physical functions. There were no significant differences in age and body mass index between the LS and non-LS groups. The percentage of skeletal muscle was lower in the LS group than in the non-LS group. Although there were no differences in the MTH of AU, PU, AF, PT, Al and PL, site-specific muscle loss was observed at RA and AT in the LS group. CS-30, 10-m walking time, zig-zag walking time, and sit-up test in the LS group were all worse than those in the non-LS group. The MTHs of RA and AT were both correlated to those physical functions. In conclusion, the LS group had site-specific muscle loss and worse physical functions. This study suggests that site-specific changes may be associated with age-related physical functions. These results may suggest what the essential characteristics of LS are.

The Measurement of Strength in Children: Is the Peak Value Truly Maximal?

It is unclear whether the measurement of maximum muscle strength in younger children can be performed accurately due to factors such as motivation and maturity (i.e., the ability to receive instruction). If there is a large change in a ratio between muscular strength and size from the youngest to the oldest, then this might provide some indication that the youngest may not have been able to voluntarily activate their muscles for reasons mentioned previously. The purpose of this study was to observe the ratio between handgrip strength (HGS) and forearm muscle thickness (MT) across differing ages in younger children. A total of 1133 preschool children (559 boys and 574 girls) between the ages of 4.5 and 6.5 years had MT and HGS measurements and calculated the ratio of HGS/MT (kg/cm). Linear regression was used to assess the impact of age and sex on the dependent variables of MT, HGS, and the HGS/MT ratio. The HGS/MT ratio increases moderately from age 4.5 to 6.5 in both boys and girls. However, the difference in this ratio was small between the age ranges in this sample. Our results indicate children as young as 4.5 may be accurately measured with the handgrip strength test.

Muscle Size and Strength of the Lower Body in Supervised and in Combined Supervised and Unsupervised Low-Load Resistance Training.

This study aimed to clarify whether low-load resistance training at a low frequency (twice a week) using body weight and elastic band improves muscle size, muscle strength, and physical functions and to compare the training effects between supervised training and a combination of supervised and unsupervised training in untrained older adults. Fifty-one older adults (ages: 57-75 years) selected to either a supervised (S) training group (n = 34) or a combined supervised and unsupervised (SU) group (n = 17). Both groups performed low-load resistance training composed of nine exercises for 12 weeks. The S group participated in supervised exercise sessions twice a week, and the SU group performed a supervised exercise session once a week and an unsupervised exercise session at home also once a week. For muscle thicknesses in the anterior aspects of the forearm, upper arm, and thigh and the posterior aspect of the thigh, group × time interactions were observed (p < 0.05). The hypertrophic effects were higher in the S group. Isometric knee extension strength and physical functions increased similarly in both groups. Low-load resistance training using body weight and elastic band twice a week for 12 weeks induces muscle hypertrophy and increases muscle strength and physical functions in older adults. Although the muscle hypertrophic effects are greater in the S group than in the SU group, the other effects were similar between the groups.

Stepwise Load Reduction Training: A New Training Concept for Skeletal Muscle and Energy Systems.

An increased ability to supply energy to skeletal muscle is expected to contribute to greater athletic performance, and therefore, a variety of training methods are used for improving these energy supply systems. These methods are classified into two broad categories: a bout of continuous exercise at a given load/intensity and intermittent bouts of exercise at a given load/intensity with recovery intervals. Interestingly, recent work suggests that a training method which starts at a high load/intensity and gradually decreases the exercise load/intensity within a given training set (stepwise load reduction training) may provide a range of adaptations. In resistance training, the load starts off high and is then reduced as the set continues which is expected to simultaneously increase muscle strength, endurance, and size. In training focused on aerobic and anaerobic metabolic systems, intensity starts off high and is then reduced as the exercise continues which is expected to simultaneously increase maximal anaerobic power, anaerobic capacity, and aerobic capacity. Because stepwise load reduction training has no recovery intervals between each load/intensity, the training effects are achieved within a short time per session (several minutes). However, only minimal evidence exists to support the effects of stepwise load reduction training; therefore, further studies with larger samples are needed.

Effects of Progressive Walking and Stair-Climbing Training Program on Muscle Size and Strength of the Lower Body in Untrained Older Adults.

The purpose of the present study was to investigate the effect of the progressive walking program on lower limb muscle size and strength and evaluated whether the stair-climbing exercise provided additional training effects when combined with the walking program. Fifteen elderly subjects (age 69 ± 1 years, height 1.63 ± 0.02 m, body weight 64.5 ± 2.0 kg) were randomly assigned to a walking group or a walking and stair-climbing group. The progressive walking program comprised continuous (week 1-8) and interval (week 9-17) exercises. The walking and stair-climbing group also performed stair climbing. Muscle thickness, strength, and walking performance were evaluated before and 8 and 17 weeks after the start of the program. The muscle thickness of the anterior and posterior parts of the thigh significantly (p < 0.05) increased in both groups. There was also a significant (p < 0.01) main effect of time in isometric maximal strength and the values expressed relative to body mass for both knee extension and flexion. However, no group × time interactions were noted. Furthermore, the percentage change of knee flexion strength after the training period was significantly (p < 0.01) correlated with the pre-intervention value. Seventeen weeks of the progressive walking program can increase thigh muscle size and strength for older adults; however, an added stair-climbing exercise may not provide additional training effects. Furthermore, the magnitude of improvement in knee flexion strength would depend on the pre-intervention value.

Association between locomotive syndrome and blood parameters in Japanese middle-aged and elderly individuals: a cross-sectional study.

BACKGROUND: Locomotive syndrome (LS) is associated with weakness and loss of function in the musculoskeletal organs. We aimed to determine the association between LS components and blood parameters in middle-aged and elderly individuals. METHODS: We included 223 middle-aged and elderly individuals in this study (104 men and 119 women; age: 40-85 years). All participants were asked to fast for at least 3 h before the venous blood samples were obtained and the hemoglobin, total protein, glycated hemoglobin (HbA1c), growth hormone, albumin and lipid profile were measured. Three functional tests, the stand-up test, the two-step test, and the 25-question geriatric locomotive function scale (GLFS) were used to assess the risk of LS. Walking speed was assessed by the 10-m walking test. Maximal isometric muscle strengths of the knee extensors were examined, and the weight bearing index (knee extension strength/body weight) was calculated. To assess an independent association between blood parameters and LS, the area under the receiver operating characteristic curve analysis (area under the curve, sensitivity, and specificity) and a binary logistic regression analysis were performed with adjustment for age. RESULTS: Of the 223 subjects, 119 (53.3%) fulfilled the diagnostic criteria for LS (including a two-step test score < 1.3, difficulty with one-leg standing from 40 cm in the stand-up test, and a 25-question GLFS score ≥ 7). Increased levels of HbA1c were significant risk factors for LS with an OR of 2.62 (OR95%CI = 1.43-4.80), as determined by a logistic regression analysis. Additionally, dehydroepiandrosterone-sulfate (DHEA-S) levels were significant only in the male subjects (OR = 0.992 [OR95%CI = 0.986-0.998]), at a threshold of 88 (AUC; 0.70, sensitivity; 79.6%, specificity; 49.1%). Moreover, 101 of 223 participants (41 men, 60 women) were analyzed for serum albumin levels, with a prevalence of LS at 55.4%, indicating that low levels of albumin were significant risk factors for LS (OR = 0.148 [OR95%CI = 0.023-0.954], p = 0.0445). CONCLUSIONS: These results suggest that higher HbA1c and lower albumin are associated with the prevalence of LS in Japanese middle-aged and elderly individuals. Furthermore, low DHEA-S levels may be useful screening tools for LS in men.

Effects of a progressive walking program on the risk of developing locomotive syndrome in elderly Japanese people: a single-arm trial.

[Purpose] This study aimed to identify the efficacy of a progressive walking program on the risk of developing locomotive syndrome among untrained elderly Japanese people. [Participants and Methods] Twenty-four untrained elderly individuals (68 ± 4 years) completed a 17-week progressive walking program. The stand-up, two-step tests and the 25-question geriatric locomotive function scale were used to assess the risk of locomotive syndrome at baseline, the 8-week midpoint (2 months), and the 17-week endpoint (4 months). Maximal isometric muscle strength of the knee extensors and flexors were measured using a dynamometer with the hip joint angle at 90° of flexion and physical function (the 30-s sit-to-stand, sit-up, 10-meter walk, and grip strength) were evaluated. [Results] The 4-month walking program significantly improved the two-step test and geriatric locomotive function scale scores. This may be attributable to the improvement in knee flexor strength and physical function. [Conclusion] A 4-month program of progressive walking effectively lowered the risk of developing locomotive syndrome in elderly Japanese people by improving knee flexor muscle strength and physical function.