Knee Extension Muscle Strength Research Articles

Effect of soft tissue, range of motion and muscle strength on deep squatting

The purpose was to clarify the effects of soft tissues such as muscles and fat, range of motion of the hip, knee and ankle, knee extension and ankle dorsiflexion muscle strength and muscle activity on deep squatting. The participants were 18 healthy university students. Physical characteristics, circumference, subcutaneous fat thickness, and range of motion were measured. After that, they performed deep squatting and lower limb muscle strength was measured. Muscle activities in lower limb during performance was also measured. Statistical tests were performed on the differences between the able group and the unable group, with each item as the dependent variable. Body weight, BMI, abdominal circumference, and tibialis anterior muscle activity were significantly lower in the able group (able to perform a deep squat), than in the unable group. Additionally, range of motion of the hip flexion and ankle dorsiflexion were significantly higher in the able group than in the unable group. It was clarified that soft tissues characteristics are connected to deep squatting in addition to range of motion.

Effects of γ-aminobutyric acid (GABA) intake in combination with exercise on muscle strength in humans with decreased mobility: a randomized, double-blind, placebo-controlled, parallel-group study

Background: Aging-related declines in skeletal muscle mass, muscle strength, and physical function are related to instability, falls, and frailty in older people, resulting in the need for nursing care. Objective: To investigate the effect of oral γ-aminobutyric acid (GABA) intake and exercise on muscle parameters in healthy subjects whose muscle strength is beginning to decline with age. Methods: A randomized, double-blind, placebo-controlled, parallel-group comparative study was conducted. Fifty subjects (over 40 years old) were randomly divided into the GABA (100 mg/day) or placebo food intake group. Subjects orally consumed the respective study substance every day for 12 weeks. They performed daily “locomotion training” as devised by the Japanese Orthopedic Society. Muscle mass, fat mass, and knee extension muscle strength were measured. Results: The two groups had no significant differences in muscle and fat mass. Compared with the placebo food group, the GABA group showed a significant improvement in knee extension muscle strength in the left and right legs at pre-dose Week 0 (at Week 6, p = 0.02). In post hoc subgroup analysis by sex, when compared with the placebo food intake group, the GABA food intake group showed significant improvement in knee extension muscle strength of the right leg at Weeks 6 (p = 0.001) and 12 (p = 0.007), the left leg at Week 6 (p = 0.02), the stronger of the left and right legs at pre-dose Week 0 (at Week 6, p = 0.001), and the weaker of the left and right legs at pre-dose Week 0 (at Week 12, p = 0.013) in males. Conclusions: These results suggest that GABA intake combined with daily exercise is effective for maintaining knee extension muscle strength, which decreases with age. Furthermore, there were no safety issues with the intake of GABA-containing food during this study. Trial registration: UMIN-CTR: UMIN000050152. Keywords: γ-Aminobutyric acid, GABA, Muscle mass, Knee extension muscle strength, Aging

The Effect of Chronic Dietary Protein Manipulation on Amino Acids' Profile and Position Sense in the Elderly Suffering from Type 2 Diabetes Mellitus.

Dietary protein with adequate essential amino acids effectively stimulates protein synthesis and improves muscle mass. Musculoskeletal disorders in lower or upper limbs are not uncommon among patients with type II diabetes mellitus (T2DM). Therefore, this study primarily examines the effects of chronic dietary protein manipulation on amino acids' profile and position sense in the elderly suffering from T2DM. A total of 26 individuals suffering from non-insulin-dependent T2DM (age > 55 years old) participated in a 12 week nutritional intervention. The subjects were randomly assigned and the control group received 0.8-1.0 g protein/kg/day, while the intervention group received 1.2-1.5 g protein/kg/day. Lean body mass, muscle strength, and position sense were assessed at baseline, as well as at the 6th and 12th week of the intervention. Only in the intervention group, the essential amino acids intake met the current nutritional recommendations (p < 0.05), while, by the 12th week, only the intervention group showed significant improvement in the muscle strength of knee (p < 0.05) and shoulder (p < 0.05) extension. On the contrary, in the control group, a significant decline in appendicular lean mass (p < 0.05) was observed by the 12th week. Position sense at the knee joint revealed a tendency for improvement in the intervention group by the 12th week (main effect of time p = 0.072). In the present investigation, it was revealed that the higher protein intake in the intervention group seemed to have positive effects on muscle strength and nearly positive effects on position sense.

Functional Limitations and Exercise Intolerance in Patients With Post-COVID Condition

Many patients with post-COVID condition (PCC) experience persistent fatigue, muscle pain, and cognitive problems that worsen after exertion (referred to as postexertional malaise). Recommendations currently advise against exercise in this population to prevent symptom worsening; however, prolonged inactivity is associated with risk of long-term health deterioration. To assess postexertional symptoms in patients with PCC after exercise compared with control participants and to comprehensively investigate the physiologic mechanisms underlying PCC. In this randomized crossover clinical trial, nonhospitalized patients without concomitant diseases and with persistent (≥3 months) symptoms, including postexertional malaise, after SARS-CoV-2 infection were recruited in Sweden from September 2022 to July 2023. Age- and sex-matched control participants were also recruited. After comprehensive physiologic characterization, participants completed 3 exercise trials (high-intensity interval training [HIIT], moderate-intensity continuous training [MICT], and strength training [ST]) in a randomized order. Symptoms were reported at baseline, immediately after exercise, and 48 hours after exercise. The primary outcome was between-group differences in changes in fatigue symptoms from baseline to 48 hours after exercise, assessed via the visual analog scale (VAS). Questionnaires, cardiopulmonary exercise testing, inflammatory markers, and physiologic characterization provided information on the physiologic function of patients with PCC. Thirty-one patients with PCC (mean [SD] age, 46.6 [10.0] years; 24 [77%] women) and 31 healthy control participants (mean [SD] age, 47.3 [8.9] years; 23 [74%] women) were included. Patients with PCC reported more symptoms than controls at all time points. However, there was no difference between the groups in the worsening of fatigue in response to the different exercises (mean [SD] VAS ranks for HIIT: PCC, 29.3 [19.5]; controls, 28.7 [11.4]; P = .08; MICT: PCC, 31.2 [17.0]; controls, 24.6 [11.7]; P = .09; ST: PCC, 31.0 [19.7]; controls, 28.1 [12.2]; P = .49). Patients with PCC had greater exacerbation of muscle pain after HIIT (mean [SD] VAS ranks, 33.4 [17.7] vs 25.0 [11.3]; P = .04) and reported more concentration difficulties after MICT (mean [SD] VAS ranks, 33.0 [17.1] vs 23.3 [10.6]; P = .03) compared with controls. At baseline, patients with PCC showed preserved lung and heart function but had a 21% lower peak volume of oxygen consumption (mean difference: -6.8 mL/kg/min; 95% CI, -10.7 to -2.9 mL/kg/min; P < .001) and less isometric knee extension muscle strength (mean difference: -37 Nm; 95% CI, -67 to -7 Nm; P = .02) compared with controls. Patients with PCC spent 43% less time on moderate to vigorous physical activity (mean difference, -26.5 minutes/d; 95% CI, -42.0 to -11.1 minutes/d; P = .001). Of note, 4 patients with PCC (13%) had postural orthostatic tachycardia, and 18 of 29 (62%) showed signs of myopathy as determined by neurophysiologic testing. In this study, nonhospitalized patients with PCC generally tolerated exercise with preserved cardiovascular function but showed lower aerobic capacity and less muscle strength than the control group. They also showed signs of postural orthostatic tachycardia and myopathy. The findings suggest cautious exercise adoption could be recommended to prevent further skeletal muscle deconditioning and health impairment in patients with PCC. ClinicalTrials.gov Identifier: NCT05445830.

Effect of Different Exercise Interventions on Grip Strength, Knee Extensor Strength, Appendicular Skeletal Muscle Index, and Skeletal Muscle Index Strength in Patients with Sarcopenia: A Meta-Analysis of Randomized Controlled Trials.

Sarcopenia is a systemic skeletal muscle disease that is more prevalent in older adults. The role of exercise in improving the disease has been demonstrated. However, due to the variety of exercise modalities, it is not clear what type of exercise provides the best benefit. The aim of this meta-analysis was to analyze the effects of different exercise modalities on grip strength, appendicular skeletal muscle index, skeletal muscle index, and knee extensor strength in elderly patients with sarcopenia. The protocol for this evaluation was registered on the PROSPERO website and the databases PubMed, WOS, Cochrane Library, and Embase were searched. Thirteen studies were included in the analysis. The results showed that exercise interventions had positive effects on grip strength and knee extension muscle strength, with resistance training being the most effective. There was no significant improvement in appendicular skeletal muscle index or skeletal muscle index. This study still has limitations. For example, age group and exercise duration were not considered. Future studies should further explore benefits in age groups as well as other relevant outcome indicators.

Effectiveness of physical therapy on physical activity and employment status in kidney transplant recipients in their sixties: a case report with literature review

BackgroundFew reports have been published on preoperative and long-term postoperative rehabilitation after kidney transplantation. Poor physical function after kidney transplantation is associated with adverse events; hence, physical function should be improved postoperatively. We report a case in which physical therapy was provided just before the operation and 12 months postoperatively to improve physical performance.Case presentationA 64-year-old man, working as a janitor and maintenance worker at a driving school, received a living-donor kidney transplant from his wife. The just before the operation assessment revealed a decline in his physical function, indicating he had become frail. Accordingly, physical therapy was initiated prior to kidney transplantation. Subsequently, his Short Physical Performance Battery score improved from 10 to 12, and his knee extension muscle strength improved from 0.38 to 0.43 kgf/kg, enabling him to resume work. The work functioning impairment scale improved from 13 to 7.ConclusionsThis case reveals that just before the operation and long-term rehabilitation is crucial in enhancing physical activity in kidney transplantation patients. Although this focused rehabilitation approach holds promise, evaluating its efficacy requires the examination of a larger cohort of cases.

Use of a Triaxial Accelerometer to Measure Changes in Gait Sway and Related Motor Function after Corrective Spinal Fusion Surgery for Adult Spinal Deformity.

Background: Adult spinal deformity is a complex condition that causes lower back pain, causing spinal imbalance and discomfort in activities of daily life. After corrective spinal surgery, patients' gait and balance abilities might not revert to normalcy and they might be at increased risk of falling. Therefore, early evaluation of such a risk is imperative to prevent further complications such as a fall, or even worse, fractures in post-surgery ASD patients. However, there has been no report of an investigation of such early changes in gait sway before and after ASD surgery. This is a prospective to investigate changes in gait sway before and following ASD surgery, using accelerometers, and also to examine motor function related to postoperative gait sway. Methods: Twenty patients were included who underwent corrective surgery as treatment for ASD, from October 2019 to January 2023. Measurement parameters included a 10 m walking test and the timed up-and-go test (TUG), gait sway was evaluated using accelerometers (root mean square; RMS), and hip flexion and knee extension muscle strength were tested. RMS included RMS vertical: RMSV; RMS anterior posterior: RMSAP; RMS medial lateral: RMSML. The radiographic spinopelvic parameters were also evaluated preoperatively and postoperatively. p < 0.05 was noted as remarkably significant. Results: Preoperative and postoperative RMSV were 1.07 ± 0.6 and 1.31 ± 0.8, respectively (p < 0.05). RMSML significantly decreased from 0.33 ± 0.2 to 0.19 ± 0.1 postoperatively (p < 0.01). However, RMSAP did not change postoperatively (0.20 ± 0.2 vs. 0.14 ± 0.1, p > 0.05). Patients' one-month postoperative hip flexor muscle strength became significantly weaker (0.16 ± 0.04 vs. 0.10 ± 0.03 kgf/kg, p = 0.002), but TUG was maintained (11.6 ± 4.2 vs. 11.7 s, p = 0.305). RMSV was negatively correlated with quadriceps muscle strength and positively with TUG. RMSAP was negatively correlated with quadriceps muscle strength. All spinopelvic parameters became normal range after surgery. Conclusions: After corrective spinal fusion for ASD patients, the gait pattern improved significantly. Iliopsoas (hip flexor) and quadriceps femoris (knee extensor) muscles may play important roles for gait anterolateral and vertical swing, respectively.

Association of taurine intake with changes in physical fitness among community-dwelling middle-aged and older Japanese adults: an 8-year longitudinal study.

Taurine has diverse valuable biological functions, including antioxidant activity and regulation of osmotic pressure. Maintaining physical fitness from middle age is important for healthy life expectancy. Although taurine administration improves muscle endurance and strength, its role in maintenance remains unclear. We aimed to clarify the longitudinal taurine intake association with fitness changes. Participants comprised men and women aged ≥40 years who participated in the third (2002-2004; Baseline) and seventh (2010-2012; Follow-up) waves of the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA) and completed a 3-day dietary weights recording survey at baseline. A table of taurine content was prepared for 751 foods (including five food groups: Seaweed; Fish and shellfish; Meat; Eggs; and Milk and dairy products) from the Standard Tables of Food Composition in Japan (1,878 foods) 2010. Four physical fitness items (knee extension muscle strength, sit-and-reach, one-leg standing with eyes closed, and maximum walking speed) were measured at baseline and follow-up. We analyzed the association of taurine intake with physical fitness change, employing a general linear model (GLM) and trend tests for baseline taurine intake and follow-up fitness change. Adjustments included baseline variables: sex, age, height, weight, educational level, self-rated health, smoking status, depressive symptoms, and clinical history. The estimated average daily taurine intake (standard deviation) was 207.5 (145.6) mg/day at the baseline. When examining the association with the four physical fitness parameters, higher taurine intake positively increased the change in knee extension muscle strength (T1; 0.1, T2; 0.8, T3; 1.1 (kgf) GLM, p < 0.05; p for trend <0.05) and reduced the decline in knee extension muscle strength in the subgroup analysis of participants aged ≥65 years (T1: -1.9, T2: -1.7, T3: -0.4 kgf; GLM p < 0.05, p for trend <0.05). No relationship was found between taurine intake and the remaining three fitness factors. Estimation of taurine intake showed that dietary taurine intake potentially contributes to the maintenance of knee extension muscle strength over 8 years among Japanese community-dwelling middle-aged and older individuals. This is the first study to investigate the association of dietary taurine intake with muscle strength.

Effect of outpatient cardiac rehabilitation on motor function and health-related quality of life in stroke survivors

BackgroundOutpatient cardiac rehabilitation (CR) is a promising tool for improving functional outcome in stroke survivors, however, evidence for improving emotional health is limited. We aimed to clarify the effects of outpatient CR following in-hospital stroke rehabilitation on health-related quality of life (HRQOL) and motor function. MethodsPatients with acute ischemic stroke or transient ischemic attack discharged directly home were recruited, and 128 patients who fulfilled criteria for insurance coverage of CR were divided into the CR (+) group (n = 46) and CR (-) group (n = 82). All patients underwent in-hospital stroke rehabilitation, and within 2 months after stroke onset, patients in the CR (+) group started a 3-month outpatient CR program of supervised sessions. Changes of motor function and HRQOL assessed by the short form-36 version 2 (SF-36) from discharge to 3 months post-discharge were compared between the two groups. ResultsTwenty-six patients in the CR (+) group completed the program and 66 patients in the CR (-) group were followed up at a 3-month examination. Least-square mean changes in 6-minute walk distance and isometric knee extension muscle strength were significantly higher in the CR (+) group than the CR (-) group (52.6 vs. 16.3 m; 10.1 vs. 3.50 kgf/kg). Improvement of HRQOL at 3 months was not observed in the CR (+) group. ConclusionsOutpatient CR following in-hospital stroke rehabilitation within 2 months after stroke onset improved exercise tolerance and functional strength but not HRQOL assessed by the SF-36 after completion of CR in the present cohort.

Factors associated with physical activity following total knee arthroplasty for knee osteoarthritis: a longitudinal study.

After total knee arthroplasty (TKA), patients' physical activity (PA) levels at 6 months are lower than those of healthy subjects. Few studies have investigated the factors associated with PA at 6 months after TKA by objectively measuring preoperative and postoperative PA intensity using an accelerometer and knee function using a goniometer and dynamometer. The purpose of this study was to determine the factors associated with PA levels at 6 months after TKA based on objective data. Eighty-two patients (mean [SD] age 74.5 [6.4] years) with moderate-to-severe knee osteoarthritis (OA) who were scheduled for TKA at the Nagoya Orthopaedic and Joint Replacement Clinic from July 2018 to July 2019 were enrolled in this longitudinal study. All patients underwent evaluations of knee function, including range-of-motion and knee-extension muscle strength; knee pain; performance in the timed up-and-go test; and accelerometer-measured PA both preoperatively and 6 months postoperatively. Factors associated with PA at 6 months after TKA were assessed using a hierarchical multiple linear regression analysis adjusted for age, sex, body mass index, and presence of diabetes mellitus. A higher average daily step count at 6 months after TKA was significantly associated with greater preoperative knee-extension muscle strength on the operated side (β = 0.155, p = 0.028) as well as a higher preoperative average daily step count (β = 0.834, p < 0.001). Furthermore, average daily time spent in moderate-to-vigorous-intensity PA postoperatively was significantly associated only with time spent in moderate-to-vigorous-intensity PA preoperatively (β = 0.723, p < 0.001). These findings indicate that a higher preoperative daily step count and greater preoperative knee-extension muscle strength on the operated side may be associated with a higher daily step count at 6 months after TKA. Factors associated with PA differed by the PA intensity level. Rehabilitation and interventions for psychosocial factors before TKA beginning when mild knee OA first occurs are expected to lead to increased PA in TKA patients.

The comparison of functional status and health-related parameters in ovarian cancer survivors with healthy controls

PurposeThe primary purpose of this study was to evaluate functional status and health-related parameters in ovarian cancer (OC) survivors and to compare these parameters with healthy controls. The secondary purpose of this study was to compare these parameters in early and advanced OC survivors.MethodsThirty-two OC survivors (n = 15 early stage; n = 17 advanced stage) with no evidence/suspicion of cancer recurrence after completing adjuvant local and systemic treatments for at least 12 months and 32 healthy controls were recruited for functional- and health-related assessments. Participants were assessed using the following methods of measuring the following: 6-min walk test (6MWT) for functional exercise capacity, 30-s chair stand test (30 s-CST) for functional fitness and muscle endurance, a handheld dynamometer for peripheral muscle strength, and a handheld dynamometer for lower extremity strength, Medical Micro RPM for respiratory muscle strength, International Physical Activity Questionnaire-Short Form (IPAQ-SF) for physical activity level, and Eastern Cooperative Oncology Group Performance Scale (ECOG-PS) for performance status, Checklist Individual Strength (CIS) for fatigue, Treatment/Gynecological Oncology-Neurotoxicity (FACT/GOG-NTX) for neuropathy, the Hospital Anxiety and Depression Scale (HADS) for anxiety and depression level, and the World Health Organization-Five Well-Being Index (WHO-5) for generic quality of life.ResultsAll OC survivors underwent surgery and chemotherapy, and only 9.4% received radiotherapy in addition to chemotherapy. The median recurrence-free period post-completion of adjuvant treatments was 24.00 (12.00–75.00) months. OC survivors had lower 6MWT (m) (p < 0.001, r = 1.50), peripheral muscle strength (p = 0.005, r = 0.72), knee extension (p < 0.001, r = 1.54), and respiratory muscle strength (maximal inspiratory pressure) (p < 0.001, r = 1.90) (maximal expiratory pressure) (p < 0.001, r = 1.68) compared to healthy controls. HADS-A (p = 0.005, r = 0.75) and CIS scores (p = 0.025, r = 0.59) were also higher in the OC survivors. Early-stage OC survivors had better 6MWT (m) than advanced-stage OC survivors (p = 0.005, r = 1.83). Peripheral muscle strength was lower in advanced-stage OC survivors (p = 0.013, r = 0.92). FACT/GOG-NTX scores were higher in early-stage OC survivors (p < 0.001, r = 1.42). No significant differences were observed between early- and advanced-stage OC survivors in other measures (p < 0.05).ConclusionThe findings suggest functional status, and health-related parameters are negatively affected in OC survivors. Additionally, higher levels of fatigue, neuropathy anxiety, and depression were reported in advanced OC survivors.

Improvement in Gait Speed Affects Short-term Improvement in Activities of Daily Living in Patients with Moderate and Severe Knee Osteoarthritis.

It is unclear whether improvements in knee pain or physical function lead to improvements in activities of daily living (ADL) and quality of life (QOL) in patients with moderate to severe knee osteoarthritis (KOA). This study aimed to investigate whether improvements in knee pain and physical function, achieved through exercise therapy, lead to improvements in ADL and QOL in patients with moderate to severe KOA. This case-control study included 18 patients with KOA. We evaluated knee range of motion, knee extension muscle strength (KEM), gait speed, knee pain, Knee Injury and Osteoarthritis Outcome Score (KOOS)-ADL, and KOOS-QOL at the first visit and after 3 months of exercise therapy. Patients were classified into the ADL and QOL improvement or no-improvement groups. Statistical analysis used split factorial analysis of variance with time and group as the main effects. When interactions were observed, post-hoc analysis was performed with two-sample t-tests. For ADL improvement, the improvements in KEM of the affected side and gait speed were statistically significant. At 3 months, the gait speed of the improvement group was significantly higher than that of the no-improvement group. For QOL improvement, there was no significant interaction for any of the factors evaluated. No factor showed significant contribution to improved QOL in patients with moderate to severe KOA. However, increased gait speed may improve ADL and contribute to the development of efficient rehabilitation programs for patients with moderate to severe KOA.

Relationship between quadriceps muscle computed tomography measurement and motor function, muscle mass, and sarcopenia diagnosis.

The quadriceps muscle is one of the human body's largest and most clinically important muscles and is evaluated using mid-thigh computed tomography (CT); however, its relationship with motor function and sarcopenia remains unclear. Herein, we investigated the relationship between the cross-sectional area (CSA) of the quadriceps muscle, CT attenuation value (CTV), dual-energy X-ray absorptiometry muscle mass measurements, and muscle strength and motor function to evaluate the relationship between muscle mass loss and motor function decline, determine the diagnostic ability for sarcopenia, and confirm the usefulness of quadriceps muscle CT evaluation. A total of 472 middle-aged and older community dwellers (254 men and 218 women) aged ≥40 years (mean age: 62.3 years) were included in this study. The quantity and quality of the quadriceps muscle were assessed using CSA and CTV (CSA×CTV) as a composite index multiplied by quality and quantity. Age-adjusted partial correlations by sex with eight motor functions (knee extension muscle strength, power, normal walking speed, fast walking speed, grip strength, sit-up ability, balance ability, and reaction time) were evaluated, including correction methods for height, weight, and body mass index (BMI). Further, the accuracy of sarcopenia diagnosis was evaluated using appendicular muscle mass with dual-energy X-ray absorptiometry measurements, grip strength, and walking speed as the gold standard, and receiver operating characteristic curves were plotted to evaluate diagnostic performance. In men, CSA and CSA×CTV were significantly associated with seven of the eight motor functions (p<0.05), excluding only balance ability. BMI-corrected CSA was significantly correlated with all eight motor functions in men and women (p<0.05). In the diagnosis of sarcopenia based on skeletal muscle index, CSA (area under the curve (AUC) 0.935) and CSA×CTV (AUC 0.936) and their correction by height (CSA/height (AUC 0.917) and CSA×CTV/height (AUC 0.920)) were highly accurate and useful for diagnosis in men but moderately accurate in women (CSA (AUC 0.809), CSA×CTV (AUC 0.824), CSA/height (AUC 0.799), CSA×CTV/height (AUC 0.814)). The present results showed that a single CT image of the quadriceps muscle at the mid-thigh is useful for diagnosing sarcopenic changes, such as loss of muscle mass, muscle weakness, and muscle function.

Impact of 14 Days of Bed Rest in Older Adults and an Exercise Countermeasure on Body Composition, Muscle Strength, and Cardiovascular Function: Canadian Space Agency Standard Measures

Introduction: Head-down bed rest (HDBR) has long been used as an analog to microgravity, and it also enables studying the changes occurring with aging. Exercise is the most effective countermeasure for the deleterious effects of inactivity. The aim of this study was to investigate the efficacy of an exercise countermeasure in healthy older participants on attenuating musculoskeletal deconditioning, cardiovascular fitness level, and muscle strength during 14 days of HDBR as part of the standard measures of the Canadian Space Agency. Methods: Twenty-three participants (12 males and 11 females), aged 55–65 years, were admitted for a 26-day inpatient stay at the McGill University Health Centre. After 5 days of baseline assessment tests, they underwent 14 days of continuous HDBR followed by 7 days of recovery with repeated tests. Participants were randomized to passive physiotherapy or an exercise countermeasure during the HDBR period consisting of 3 sessions per day of either high-intensity interval training (HIIT) or low-intensity cycling or strength exercises for the lower and upper body. Peak aerobic power (V̇O2peak) was determined using indirect calorimetry. Body composition was assessed by dual-energy X-ray absorptiometry, and several muscle group strengths were evaluated using an adjustable chair dynamometer. A vertical jump was used to assess whole-body power output, and a tilt test was used to measure cardiovascular and orthostatic challenges. Additionally, changes in various blood parameters were measured as well as the effects of exercise countermeasure on these measurements. Results: There were no differences at baseline in main characteristics between the control and exercise groups. The exercise group maintained V̇O2peak levels similar to baseline, whereas it decreased in the control group following 14 days of HDBR. Body weight significantly decreased in both groups. Total and leg lean masses decreased in both groups. However, total body fat mass decreased only in the exercise group. Isometric and isokinetic knee extension muscle strength were significantly reduced in both groups. Peak velocity, flight height, and flight time were significantly reduced in both groups with HDBR. Conclusion: In this first Canadian HDBR study in older adults, an exercise countermeasure helped maintain aerobic fitness and lean body mass without affecting the reduction of knee extension strength. However, it was ineffective in protecting against orthostatic intolerance. These results support HIIT as a promising approach to preserve astronaut health and functioning during space missions, and to prevent deconditioning as a result of hospitalization in older adults.

Relationship between Mild Cognitive Impairment, Pre-Frailty, Physical and Psychological Functioning, and Functional Capacity among Community-Dwelling Older Adults.

Mild cognitive impairment (MCI) is associated with a high risk of dementia. Reportedly, 54.6% of older adults with MCI fall into the pre-frailty category. However, it is unclear what differences exist in older adults with regard to their physical, psychological, and functional capacities, which depend on MCI, pre-frailty, or a combination of the two. This study aimed to examine the differences between the association between physical function, psychological function, and functional capacity by examining a combination of MCI and pre-frailty among community-dwelling older Japanese individuals. The participants in the analysis were 236 older people living in the community. They were classified into four groups, as follows: normal, MCI only, pre-frailty only, and pre-frailty/MCI; furthermore, their physical, psychological, and functional capacities were compared. In addition, a multinomial logistic regression analysis was performed using MCI and pre-frailty as dependent variables. No associated factors were identified for MCI only, and a depressive mood was only associated with pre-frailty. When pre-frailty and MCI were combined, knee extension muscle strength, fastest gait speed, the s30 s chair stand test, depressed moods, and the instrumental activities of daily living (IADL) were correlated. Our results suggest that when MCI and pre-frailty are combined, declines in both physical and psychological functions and IADL are likely to occur.

Effectiveness of single leg standing up exercise for recovery of knee muscle strength and lower extremity motion function following anterior cruciate ligament reconstruction

PurposeWe investigated the effectiveness of single-leg standing exercise (SLSE) as a home-based self-exercise for the recovery of knee joint muscle strength and lower limb motor function after anterior cruciate ligament (ACL) reconstruction. MethodsIn addition to postoperative rehabilitation, 55 patients who underwent ACL repair were asked to begin SLSE as a home-based self-exercise 50 times per day using a platform elevated at 40 ​cm for 2 months, 30 ​cm at 3 months, 20 ​cm at 4 months, and 10 ​cm at 5 months (intervention group). Sixty-four patients who underwent ACL reconstruction and followed the existing rehabilitation protocol were included in the control group. Isokinetic knee extension and flexion at 60° angular velocity at 3, 8, and 10 months after surgery and lower limb motor function performance at 8 and 10 months after surgery were compared within and between the two groups. ResultsKnee extension and flexion muscle strength and lower-extremity motor function recovered over time in both groups. There were no significant differences in knee extension and flexion muscle strength between the two groups at 3 months after surgery. However, knee extension strength, flexion strength, and triple hop test (THT) results were significantly higher in the intervention group (p ​< ​0.01) 8 months after surgery. In addition, knee flexion strength and THT were significantly higher in the intervention group (p ​< ​0.01) 10 months after surgery. ConclusionsThe results of this study suggest that SLSE can be an effective exercise for recovering knee joint muscle strength and lower limb motor function.

Effects of Inspiratory Muscle Training in Patients With Pulmonary Hypertension

The study aimed to examine the effects of inspiratory muscle training (IMT) in patients with pulmonary hypertension (PH). A total of 24 patients with PH were included in the randomized controlled evaluator-blind study. IMT was performed at 40% to 60% of the maximal inspiratory pressure for 30min/d, 7d/wk (1day supervised) for 8weeks. Respiratory muscle strength, dyspnea, diaphragm thickness (DT), pulmonary functions, 24-hour ambulatory blood pressure (BP), arterial stiffness, exercise capacity, upper extremity functional exercise capacity, physical activity levels, fatigue, anxiety-depression levels, activities of daily living (ADL), and quality of life were evaluated. A total of 24 patients (treatment=12, control=12) completed the 8-week follow-up. There was no significant difference between the patient groups in terms of demographic and clinical characteristics (p>0.05). Considering the change between the groups in the treatment and control groups, brachial and central BP, dyspnea, respiratory muscle strength, DT in total lung capacity, knee extension muscle strength, functional exercise capacity, upper extremity functional exercise capacity, physical activity, ADL, fatigue, anxiety, and quality of life improved in favor of the IMT group (p<0.05). In conclusion, IMT has improved brachial and central BP, dyspnea, respiratory muscle strength, DT in total lung capacity, knee extension muscle strength, functional exercise capacity, upper extremity functional exercise capacity, physical activity, ADL, fatigue, anxiety, and quality of life compared with the control group. IMT is an effective method in cardiopulmonary rehabilitation for patients with PH.

Knee Extensor Weakness Potently Predicts Postoperative Outcomes in Older Gastrointestinal Cancer Patients

ObjectivesMuscle weakness, assessed by grip strength, has been shown to predict postoperative mortality in older patients with cancer. Because lower extremity muscle strength well reflects physical performance, we examined whether lower knee extension muscle strength predicts postoperative mortality better than grip strength in older patients with gastrointestinal cancer. DesignProspective, observational study in a single institution. Setting and ParticipantsA total of 813 patients (79.0 ± 4.2 years, 66.5% male) aged 65 years or older with gastrointestinal cancer who underwent preoperative evaluation of grip strength and isometric knee extension muscle strength between April 2012 and April 2019 were included. MethodsThe study participants were prospectively followed up for postoperative mortality. Muscle weakness was defined as the lowest quartile of grip strength or knee extension strength (GS-muscle weakness and KS-muscle weakness, respectively). ResultsAmong the study participants, 176 patients died during a median follow-up of 716 days. In the Kaplan-Meier analysis, we found that patients with both GS-muscle weakness and KS-muscle weakness had a lower survival rate than those without muscle weakness. As expected, higher clinical stages and abdominal and thoracic surgeries compared with endoscopic surgery were associated with increased all-cause mortality. In addition, we found that KS-muscle weakness, but not GS-muscle weakness, was an independent prognostic factor after adjusting for sex, body mass index, cancer stage, surgical technique, and surgical site in the Cox proportional hazard model. Conclusions and ImplicationsIn older patients with gastrointestinal cancer, muscle weakness based on knee extension muscle strength can be a better predictor of postoperative prognosis than muscle weakness based on grip strength.

Effect of diabetes mellitus on physical activity in patients with knee osteoarthritis: A cross-sectional study.

Knee osteoarthritis (OA) may be comorbid with diabetes mellitus (DM), and physical activity is a recommended lifestyle strategy for both diseases. The present study investigated the physical activity differences by intensity between knee OA patients with or without DM, and evaluated if physical activity was associated with the presence of DM in knee OA patients. A total of 183 patients (mean age 74.9 ± 6.4years) with moderate-to-severe knee OA underwent evaluation of knee function (i.e., knee flexion/extension range-of-motion, knee-extension muscle strength, and knee pain), the timed up-and-go (TUG) test, and physical activity measurement using an accelerometer. Physical activity by intensity was compared between knee OA patients with and without DM. The association between physical activity, including knee function and the TUG test time, and DM was assessed. The 2 groups (with or without DM) did not differ significantly in knee OA severity or age. Compared to knee OA patients without DM, knee OA patients with DM had a significantly lower average daily step count (p < 0.001), and significantly shorter times spent performing light-intensity physical activity (LPA; p < 0.001) and moderate-to-vigorous-intensity physical activity (MVPA; p = 0.006). After adjusting for age, sex, and body mass index, we found that a lower average daily step count and shorter LPA time significantly correlated with DM (β = -0.200, p = 0.006; β = -0.216, p = 0.004, respectively) and a longer TUG test time (β = -0.196, p = 0.014; β = -0.208, p = 0.011, respectively). A shorter MVPA time significantly correlated with lower contralateral knee-extension muscle strength (β = 0.187, p = 0.032). Knee OA patients with DM had significantly lower physical activity levels than those without DM. Furthermore, the presence of DM correlated with a lower step count and a shorter LPA time in knee OA patients.

Not only muscle mass but also muscle quality is associated with knee extension muscle strength in patients with hip fractures

This study aimed to assess the relationship between isometric knee extension muscle strength on the operated or nonoperated sides and PhA in patients with hip fractures at approximately 6months postoperatively. This study was a cross-sectional study. Skeletal muscle index (SMI), PhA, knee extension muscle strength on the operated and nonoperated sides, and other physical function variables were assessed at approximately 6months postoperatively. To identify predictors of knee extension muscle strength on the operated and nonoperated sides, hierarchical multiple regression analysis was performed. A total of 90 patients with hip fractures were included (mean age, 80.1 ± 6.9years). SMI (0.45) and PhA on the operated side (0.27) were the significant associated factors extracted for isometric knee extension muscle strength on the operated side (standardized partial regression coefficients), independent of age, sex, and body mass index (BMI). Movement control during one-leg standing on the nonoperated side (0.26), SMI (0.32), and PhA on the nonoperated side (0.40) were the significant associated factors extracted for isometric knee extension muscle strength on the nonoperated side, independent of age, sex and BMI. Our results revealed that the decrease in isometric knee extension muscle strength on the operated and nonoperated sides in patients with hip fractures at approximately 6months postoperatively was associated with not only a decrease in skeletal muscle mass but also a decrease in muscle quality, characterized by a decreased PhA.