Knee Extensor Strength Research Articles

Effects of inclined treadmill training on inadequate ankle control during walking in individuals after stroke: A pilot randomized controlled trial.

Inadequate ankle control influences walking ability in people after stroke. Walking on inclined surface activates ankle muscles and movements. However, the effect of inclined treadmill training on ankle control is not clear. To investigate the effects of inclined treadmill training on ankle control in individuals with inadequate ankle control after chronic stroke. This was a randomized single-blinded study. Eighteen participants were randomly assigned to receive 12 sessions of 30 min inclined (n = 9) or regular (n = 9) treadmill training and 5 min over-ground walking training. The outcomes included ankle control during walking, muscle strength of affected leg, walking performance, and stair climbing performance. Inclined treadmill training significantly improved ankle dorsiflexion at initial contact (p = 0.002), increased tibialis anterior activities (p = 0.003 at initial contact, p = 0.006 in swing phase), and decreased dynamic plantarflexors spasticity (p = 0.027) as compared with regular treadmill training. Greater improvements were also shown in stair climbing with affected leg leading (p = 0.006) and affected knee extensors strength (p = 0.002) after inclined treadmill training. Inclined treadmill training was proposed to improve inadequate ankle control after chronic stroke. Inclined treadmill training also improved the stair climbing ability accompanied with increased muscle strength of the affected lower extremity.

Training-induced improvements in knee extensor force accuracy are associated with reduced vastus lateralis motor unit firing variability.

New Findings What is the central question of this study? Can bilateral knee extensor force accuracy be improved following 4 weeks of unilateral force accuracy training and are there any subsequent alterations to central and/or peripheral motor unit features? What is the main finding and its importance? In the trained limb only, knee extensor force tracking accuracy improved with reduced motor unit firing rate variability in the vastus lateralis, and there was no change to neuromuscular junction transmission instability. Interventional strategies to improve force accuracy may be directed to older/clinical populations where such improvements may aid performance of daily living activities. Muscle force output during sustained submaximal isometric contractions fluctuates around an average value and is partly influenced by variation in motor unit (MU) firing rates. MU firing rate (FR) variability seemingly reduces following exercise training interventions; however, much less is known with respect to peripheral MU properties. We therefore investigated whether targeted force accuracy training could lead to improved muscle functional capacity and control, in addition to determining any alterations of individual MU features. Ten healthy participants (seven females, three males, 27 ± 6 years, 170 ± 8 cm, 69 ± 16 kg) underwent a 4‐week supervised, unilateral knee extensor force accuracy training intervention. The coefficient of variation for force (FORCECoV) and sinusoidal wave force tracking accuracy (FORCESinu) were determined at 25% maximal voluntary contraction (MVC) pre‐ and post‐training. Intramuscular electromyography was utilised to record individual MU potentials from the vastus lateralis (VL) muscles at 25% MVC during sustained contractions, pre‐ and post‐training. Knee extensor muscle strength remained unchanged following training, with no improvements in unilateral leg‐balance. FORCECoV and FORCESinu significantly improved in only the trained knee extensors by ∼13% (P = 0.01) and ∼30% (P < 0.0001), respectively. MU FR variability significantly reduced in the trained VL by ∼16% (n = 8; P = 0.001), with no further alterations to MU FR or neuromuscular junction transmission instability. Our results suggest muscle force control and tracking accuracy is a trainable characteristic in the knee extensors, which is likely explained by the reduction in MU FR variability which was apparent in the trained limb only.

Can phase angle from bioelectrical impedance analysis associate with neuromuscular properties of the knee extensors?

Maintenance and improvement of neuromuscular functions is crucial for everyone regardless of age. An easy way to assess neuromuscular properties without muscle contraction is useful especially for those who cannot perform strenuous muscular force production, such as older adults and patients with orthopedic or cognitive disorders. Bioelectrical impedance analysis (BIA) can assess body electrical properties e.g., phase angle (PhA) which is regarded as muscle quantity/quality index. The purpose of this study was to investigate associations of PhA with neuromuscular properties of the knee extensors in 55 young (n = 23) and older (n = 32) adults. The values of PhA of the right thigh and whole-body were determined with BIA at 50 kHz. The participants performed 4-s maximal voluntary isometric contraction (MVIC) to measure peak torque (PTMVIC), and 1-s brief MVIC to assess rate of torque development (RTD) over the time interval of 0–200 ms. As markers of physiological mechanisms of muscle force production, twitch contractile properties (peak twitch torque, rate of twitch torque development, and time-to-peak twitch torque) of the knee extensors obtained by femoral nerve electrical stimulation, and muscle activity assessed as root mean square values of electromyographic activity (EMG-RMS) during PTMVIC and RTD measurements were measured. Thigh and whole-body PhA significantly correlated with PTMVIC (r ≥ 0.555, p < 0.001) and electrically evoked twitch parameters (peak twitch torque, rate of twitch torque development, and time-to-peak twitch torque; |r| ≥ 0.420, p ≤ 0.001), but not RTD (r ≤ 0.237, p ≥ 0.081) or EMG-RMSs (|r| ≤ 0.214, p ≥ 0.117). Stepwise multiple linear regression analysis revealed that thigh PhA was selected as a significant variable to predict PTMVIC but not RTD. Whole-body PhA was not selected as a significant variable to predict PTMVIC or RTD. In conclusion, both thigh and whole-body PhA can associate with maximal voluntary muscle strength of the knee extensors, and this association may be due to intrinsic contractile properties but not neural aspects. Regarding prediction of the knee extensor strength, thigh PhA is preferable as the predictor rather than whole-body PhA which is used as a widely acknowledged indicator of sarcopenia.

BJS Prize 1 Postoperative electrical muscle stimulation attenuates loss of muscle mass and function following major abdominal surgery: A split body randomised control trial

Abstract Aims Significant loss of muscle mass and function occurs after major abdominal surgery. Neuromuscular electrical stimulation (NMES) has been shown to reduce muscle atrophy in some patient groups, but evidence in postoperative patients is limited. This study assesses the efficacy of NMES in attenuating muscle atrophy following major abdominal surgery. Methods Fifteen patients undergoing open colorectal resection were recruited to a split body randomised control trial and their lower limbs randomised to control (CON) or NMES (STIM). The STIM limb underwent 15 minutes of quadriceps NMES twice daily on postoperative day (POD) 1 to 4. Ultrasound measurement of Vastus Lateralis (VL) cross sectional area (CSA) and muscle thickness (MT) was made preoperatively and on POD 5, as was dynamometer measurement of knee extensor strength (KES). All outcomes were analysed using linear mixed model techniques. The study was approved by NHS research ethics committee (ref 20/EM/069). Results NMES significantly reduced the loss of CSA (-2.52% vs -9.16%, p&amp;lt;0.001), MT (-2.76% vs -8.145, p=0.001) and KES (-10.35% vs -19.69%, p=0.03). No adverse events occurred, and patients reported that NMES caused minimal or no discomfort. Conclusions NMES reduces loss of muscle mass and function following major abdominal surgery and may be an important tool in aiding recovery to normal activity levels. This will be especially important in preventing postoperative loss of independence in the increasingly physiologically frail patients undergoing major abdominal surgery. Further studies should establish the efficacy of bilateral whole-leg NMES for improving patient-centred outcomes.

WE4.6 Postoperative muscle atrophy: an overlooked cause of morbidity

Abstract Aims A significant proportion of patients never fully recover baseline activity levels following major abdominal surgery. Postoperative muscle atrophy may be a major contributing factor to this, but is often overlooked. This study aimed to quantify the degree of muscle loss in patients undergoing routine recovery following major abdominal surgery and in patients admitted to critical care. Methods Fifteen patients undergoing major open colorectal resection were recruited. Cross surface area (CSA) and muscle thickness (MT) of a quadriceps muscle, Vastus Lateralis (VL) were measured pre-operatively and on post-operative day (POD) 5 using ultrasound. Knee extension strength was also measured pre-operatively and on POD5 using a handheld dynamometer. A systematic literature review was performed to identify studies reporting muscle loss in patients admitted to an intensive treatment unit (ITU), with pooled means of changes in quadriceps muscle CSA calculated. Results By POD 5 VL CSA had decreased by 9.16% (± 2.0), and MT had decreased by 8.14% (± 5.93). Associated with this, knee extensor strength decreased by 19.69% (± 12.91). Systematic review identified 4 studies reporting muscle loss in ITU patients, including a total of 126 patients. Pooled mean of quadriceps CSA in patient admitted to ITU decreased by 13.9% (-12.5% -20.75%) by POD7. Conclusions Major abdominal surgery is associated with a significant loss of muscle mass and function. Losses are larger in patients requiring ITU admission. This may have a significant impact on patients’ full recovery to baseline function and further work is required to investigate this.

Fortalecimento do quadríceps através do método Kaatsu Training em mulheres com dor femoropatelar

ABSTRACT This is a cross-sectional, comparative, and randomized study aimed to evaluate the effects of the partial vascular occlusion technique (Kaatsu Training) associated with low load exercises in the muscle strengthening of quadriceps in women with patellofemoral pain. We evaluated 18 women with patellofemoral pain, aged from 18 to 35 years, allocated into two groups. The experimental group performed the strengthening with blood flow reduction with the aid of a sphygmomanometer, associated with low load (≅20% RM). Whereas the control group performed exercises with the same load, but without blood flow reduction. The treatment was performed three times a week for six weeks, totaling 18 sessions. We used the numerical pain rating scale (NPRS) and the anterior knee pain scale (AKPS) questionnaire for evaluation; we evaluated the muscle strength of knee extensors by the digital dynamometer. The results showed that the partial vascular occlusion technique significantly improved the values of quadriceps strength gain in the right, 6.22kg (p=0.03) and left limb, 6.98kg (p=0.04), in women with patellofemoral pain. Therefore, training with partial vascular occlusion can be useful for strengthening of the knee extensor musculature in women with patellofemoral pain who, because of the pain, have low tolerance to high load exercises for muscle strengthening. An effective, safe and cost-effective technique, which does not require an investment in a leg extension machine, since, with a cuff, low load exercises can offer significant results.

Residual limb strength and functional performance measures in individuals with unilateral transtibial amputation

BackgroundIndividuals with lower limb amputation exhibit lower residual limb strength compared to their sound limb. Deficits in residual limb knee flexion and extension strength may impact functional performance during tasks relevant to daily living. Research questionDoes knee flexor and extensor strength in the residual limb impact functional outcome measures, such as walking energetics and performance metrics, in individuals with unilateral transtibial amputation? MethodsFourteen individuals with traumatic unilateral transtibial amputation were recruited for this observational study. Participants completed metabolic testing at three standardized speeds based on leg length, as well maximum isokinetic knee flexion and extension strength for both residual and sound limbs. Participants also completed a series of functional outcome tests, including a two-minute walk test, timed stair ascent test, and four-square step test. Walking energetics (metabolic cost, heart rate, and rating of perceived exertion) and performance metrics were compared to percent deficit of residual limb to sound limb knee flexion and extension muscle strength. A linear regression assessed significant relationships (p < 0.05). ResultsA significant relationship was observed between percent deficit of knee extension strength and heart rate (p = 0.024) at a fast walking speed. Additionally, percent deficit knee flexion strength related to rating of perceived exertion at slow and moderate walking speeds (p = 0.038, p = 0.024). Percent deficit knee extension strength related to two-minute walk time performance (p = 0.035) and percent deficit knee flexion strength related to timed stair ascent time (p = 0.025). SignificanceThese findings suggest the importance of strength retention of the residual limb knee flexion and extension musculature to improve certain functional outcomes in individuals with unilateral transtibial amputation.

O101 Increased contractile activity through electrical stimulation attenuates postoperative loss of muscle mass and function, even in the presence of inadequate nutrition

Abstract Introduction Significant muscle atrophy occurs after major abdominal surgery. Lack of physical activity and protein intake may play a significant role. This study assesses the efficacy of neuromuscular electrical stimulation (NMES) in attenuating loss of muscle mass and function following open colorectal resection. Methods Fifteen patients were recruited, and their lower limbs randomised to control (CON) or NMES (STIM). Vastus Lateralis (VL) cross sectional area (CSA), muscle thickness (MT) and knee extensor strength (KES) were measured preoperatively and repeated on postoperative day (POD) 5. Dietary intake was recorded, and nutritional intake calculated. Fifteen minutes of NMES was applied to the quadriceps of the STIM leg twice a day on POD 1–4. All outcomes were analysed using linear mixed model approaches. The study was approved by the NHS REC (ref 20/EM/069). Results NMES significantly reduced the loss of CSA (mean difference (MD) 1.18, 95%CI: 0.75–1.61, p&amp;lt;0.001), MT (MD 0.12, 95%CI: 0.04–0.2, p=0.001) and KES (MD 4.48, 95%CI: 0.00–8.97, p=0.03). Total energy and protein intakes over POD1 - 4 were 42.6% (± 19.7) and 21.1% (± 11.4) of the ESPEN recommended daily amount for perioperative patients. No adverse events occurred, and patients reported that NMES caused minimal or no discomfort. Conclusion NMES has been demonstrated to reduce loss of muscle mass and function following major abdominal surgery and may be an important tool in aiding recovery to normal functional state. Further studies should establish the efficacy of bilateral whole-leg NMES for improving patient centred outcomes. Take-home message Loss of muscle mass and function after major abdominal surgery causes significant morbidity. Neuromuscular electrical stimulation reduces this muscle loss and should be investigated further as a potential therapy.

The Relationship Between Edema and Body Functions in Patients With Chronic Kidney Disease: A Preliminary Study.

Introduction: Chronic kidney disease (CKD) is known to be a risk factor for falls. In addition, numerous factors such as impaired body balance and loss of muscle mass were reported as risk factors for falls. Patients with CKD often have edema in their lower extremes. In Japan, edema, as well as physical factors, are listed as fall assessment items. Little is known about the relation between body functions and edema in patients with CKD. Thus, we conducted a multivariate regression analysis to investigate the factors related to knee extension muscle strength and dynamic balance in motion (TUG).Materials and methods: Thirty patients with CKD participated in this study. The basic characteristics were sex, age, blood pressure, body mass index (BMI), and medications. The laboratory data were estimated glomerular filtration rate (eGFR), hemoglobin (Hb), and C-reactive protein (CRP). Edema and muscle mass was measured by using InBody S10 (Inbody Japan Inc., Tokyo, Japan). The balance function while standing at rest and motion was measured as the total trajectory length of the center of gravity and the index of postural stability (IPS) using a kinetogravicorder 7100 (Anima Inc., Tokyo, Japan). Dynamic balance was assessed by the timed up & go (TUG) test. Knee extension muscle strength was measured by the Micro Total Analysis System (μ-Tas) F-1 (Anima Inc., Tokyo, Japan) test. Nutritional assessment was measured by the geriatric nutritional risk index (GNRI). Activities of daily living were measured using the functional independence measure (FIM). We conducted a multivariate regression analysis to investigate the factors related to knee extension muscle strength and dynamic balance in motion.Results: Extracellular water/total body water (ECW/TBW) was not significantly correlated with balance at rest and IPS. The ECW/TBW was associated with knee extension muscle strength, TUG, albumin (Alb), Hb, and GNRI with statistical significance. After adjusting for sex and age, knee extension muscle strength was associated with ECW/TBW and TUG (p=0.044). The TUG was also associated with ECW/TBW after being adjusted for age and sex (p=0.046). Conclusion: Patients with CKD who have edema may have decreased knee extensor strength and body balance function. Investigation of knee extension muscle strength and the body balance test in addition to the presence of leg edema at the time of physical examination may help predict a functional decline in CKD patients.

Pre-operative knee extensor and flexor torque after secondary ACL rupture: a comparative retrospective analysis

BackgroundSecondary anterior cruciate ligament (ACL) ruptures are a relevant clinical concern after surgical treatment of a primary ACL rupture. However, there is a lack of scientific evidence related to the role of muscle strength prior to revision surgery in a second ACL rupture. The aim of this study was to assess differences in knee extensor and flexor strength in patients before primary and secondary ACL reconstruction compared to healthy controls.MethodsIn total, n = 69 age, weight and sex matched individuals were included in the study: n = 23 patients with isolated primary ACL rupture, n = 23 with secondary ACL rupture, and n = 23 matched healthy controls. Maximal isokinetic knee extension and flexion torque normalized to body mass was assessed for both legs.ResultsFor patients with secondary ACL ruptures, torques were reduced in the non-injured (extension: 1.94 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.25 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.70 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.14 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. For patients with a primary ACL rupture torques were reduced in the non-injured (extension: 1.92 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.24 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.38 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.01 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. There were no differences between patients with primary and secondary ruptures, except of the knee extension on the injured leg showing higher values after a secondary ACL rupture (1.38 Nm/kg vs. 1.70 Nm/kg, p < 0.05).ConclusionsThe findings indicate that maximal knee torques were significantly reduced in patients with primary and secondary ACL ruptures before surgical reconstruction for the non-injured and injured leg as compared to healthy controls. Further investigations are needed to assess strength abilities before and after a second revision within a prospective design.

Isokinetic Muscle Strength in Elite Soccer Players 3 and 6 months After Anterior Cruciate Ligament Reconstruction.

Milutinović, A, Jakovljević, V, Dabović, M, Faude, O, Radovanović, D, and Stojanović, E. Isokinetic muscle strength in elite soccer players 3 months and 6 months after anterior cruciate ligament reconstruction. J Strength Cond Res 37(4): e297-e304, 2023-The aim of this study was to evaluate interlimb symmetry in quadriceps and hamstring peak torque of elite soccer players at 3 months (stage 1) and 6 months (stage 2) after anterior cruciate ligament (ACL) reconstruction. Eight male professional soccer players competing at the highest level across different European countries, who had undergone ACL reconstruction, participated in this study. All patients underwent a supervised physiotherapy program after surgery. Data analyses included the use of separate two-way repeated-measures analyses of variance and effect sizes. Although knee extensor and flexor strength of the non-injured limb was found to be relatively unaltered ( g = -0.10 to 0.00) between stage 1 and stage 2, comparisons across time points revealed moderate improvements in quadriceps peak torque ( p = 0.01, g = 0.52), hamstring peak torque ( p = 0.07, g = 0.51), and hamstring:quadriceps (H/Q) ratio ( p = 0.03, g = -0.68) of the injured leg, as well as small-large improvements in the quadriceps ( p = 0.004, g = 1.24) and hamstring limb symmetry index (LSI) ( p = 0.056, g = 0.41). A time-dependent moderate-large asymmetry observed at stage 1 between the injured and noninjured leg in quadriceps peak torque ( p < 0.001, g = -1.83), hamstring peak torque ( p = 0.157, g = -0.67), and the H:Q ratio ( p = 0.06, g = 1.01), as well as between the hamstring and quadriceps LSI ( p = 0.03, g = -0.74) was eliminated at stage 2 ( g = -0.31 to 0.42). Our findings indicate the importance of supervised and comprehensive therapy, as well as strength screening to assist in recovery aimed at optimizing identified strength deficits following ACL reconstruction.

Lower limb muscle quality and phase angle contribute to the reduced walking speed among older adults.

This cross-sectional study aimed to determine the predictors of a walking speed <1m/s. Factors associated with the health of muscle cells, including the phase angle analyzed using bioimpedance analysis, answers to the mini-nutritional assessment-short form, albumin levels, leg muscle quality and vitamin D levels, were assessed. The study participants were outpatients from the Locomotor Frailty Outpatient Clinic which was established at our center in 2016 (231 women, 76.5 ± 7.6 years; 137 men, 78.0 ± 6.3 years). Participants were classified into two groups, with 1m/s walking speed as the cutoff value. Binominal logistic regression analysis was performed with walking speed as the dependent variable, and age, leg muscle quality, mini-nutritional assessment-short form answers, albumin levels, vitamin D levels and the phase angle as explanatory variables. Leg muscle quality was defined as the mean value of both lower limbs' isometric knee extensor strength, divided by the mean value of both lower limbs' muscle mass through bioimpedance analysis. The explanatory variables associated with decreased walking speed among women were leg muscle quality (P=0.004, odds ratio: 0.57) and phase angle (P=0.017, odds ratio: 0.42). Men were also more likely to have leg muscle quality (P=0.004, odds ratio: 0.43). Leg muscle quality and the phase angle of lower extremities were independently associated with low walking speeds (<1m/s) among older outpatients. Geriatr Gerontol Int 2022; 22: 603-609.

Paper 24: The Power of Information: Influence of Interim Function Assessments on Patient Outcomes at the time of Return to Sport Progression Following Anterior Cruciate Ligament Reconstruction

Objectives:The administration of return to sport assessments have become common in patients following Anterior Cruciate Ligament Reconstruction (ACLR). However, they are often administered after the time of clinical supervision which may leave patients without access to clinical personnel to appropriately address the functional deficits identified. It is currently unknown if patient outcomes would benefit from interim functional assessments while under clinical supervision. The purpose of this study is to compare patient outcomes at the time of return to sport (RTS) progression between those with a prior interim assessment and those without. We hypothesize that patients with prior interim assessments will demonstrate stronger and more symmetric quadriceps strength, greater hopping performance, and higher subjective function.Methods:Patients following ACLR were retrospectively identified through an ongoing RTS assessment program where patients were referred from a sports medicine subspecialist orthopedic clinic to complete a battery of functional assessments This program assessed knee extensor and flexor strength (Nm/kg) and symmetry (%) and patient reported outcomes. Patients were stratified into “Single Test”: first assessment between 6- and 9-months post-ACLR and “Repeat Test”: prior assessment performed at least 2-months before RTS assessment between 6- and 9-months post-ACLR (Figure 1). Patients were matched based on time post-surgery, age, pre-injury activity level, and graft type.Results:A total of 392 patients were included (Single Test n=303, Repeat Test n=89.) Once matched, 169 patients (21.1±7.0 years, 7.3±.9 mo. post-ACLR) were analyzed (n=69 per group, Figure 2.) Controlling for age, activity level, graft type, and time of the assessment, Repeat Test patients demonstrated higher measures of subjective function (P=.028) and greater knee flexion symmetry (P=.006) compared to Single Test patients. There were no differences in quadriceps strength (P=.82) and symmetry (P=.18) between groups.Conclusions:Patients that received interim functional assessments reported better subjective function and higher hamstring symmetry at the time of return to sport progression compared to patients that completed their first and only assessment at this time-point. Interim referral for functional assessments may identify limitations which medical provides can address prior to the time of RT progression.

Correlation between dynamic balance ability and lower limb muscle strength of university students

Objective: To study the correlation between dynamic balance ability and lower limb muscle strength of university students. Methods: 50 students of Zunyi Medical University (23 boys and 27 girls) were selected as the subjects. The dynamic balance ability of university students was tested by the YBT test system. Isokinetic muscle strength tester tests knee flexion and extension muscle strength under different angular velocity conditions. Results: 1) At different angular velocities, there was a moderate positive correlation between knee flexion and extension muscle strength and YBT reaching all directions. Only when the angular velocity was set to 200° / s, there was a low positive correlation between knee flexion muscle strength and the front side of the YBT test. 2) There is a more significant correlation between the maximum distance of each direction of dynamic balance and the peak torque of knee extensor than that of flexor. Research conclusions: For university students, there is a significant indigenous correlation between the directions of YBT arrival, and the correlation between the posterolateral and the posterolateral is stronger. The stronger the lower limb muscle strength is, the better the dynamic balance ability is, and the correlation between dynamic ability and knee extensor muscle strength is higher, which may be related to the fact that knee flexion control balance can more effectively activate knee extensor muscle group. University students generally have bilateral asymmetry of the lower limbs.

남성 심부전 환자의 넙다리 네갈래근 근력이 최대 유산소 능력과 재입원에 미치는 영향

Purpose: The cardiopulmonary exercise test (CPET) is widely used to evaluate the clinical prognosis in patients with heart failure (HF). However, some patients with HF cannot perform CPET at maximal exercise intensity because of unstable medical condition or musculoskeletal problems. Thus, the study aimed to investigate the effects of quadriceps maximal voluntary isometric contraction (Q-MVIC) strength on aerobic capacity and re-hospitalization (RH). Methods: Patients with HF (n = 60, 59.03 ± 13.4 years, male 100%) were recruited in this study. We evaluated the Q-MVIC strength and aerobic capacity after discharge from hospitalization and followed up the RH rate during home-based self-care periods. Results: The RH (n = 15, 64.00 ± 14.69) group showed significantly lower Q-MVIC strength (p = .028) than the no RH(NRH, n = 45, 57.78 ± 13.15) group. In addition, the RH group showed significantly lower peak VO2 (p &lt; .001) than the NRH group. Moreover, the Q-MVIC strength and peak VO2 demonstrated significant correlation (r = .414, p &lt; .001). Conclusion: Our study showed that the knee extensor strength has strong predictive values on aerobic capacity and RH rate in patients with HF.

Interrelationship among thigh intermuscular adipose tissue, cross-sectional area, muscle strength, and functional mobility in older subjects.

The aim of this cross-sectional study was to investigate the association between lower limb strength, muscle mass and composition, and balance ability in elders.Thirthy-four older participants (Age: 65.6 ± 4.73 years; male = 10 and female = 24) were assessed for muscle strength (maximal isometric strength of knee extensors and one repetition maximum by leg press, the one repetition maximum [1RM]), balance and gait capacity (Mini-BESTest), body composition by whole-body dual energy x-ray absorptiometry (obtaining Appendicular Skeletal Muscle Mass Index, ASMMI), and magnetic resonance imaging of thigh to evaluate Intermuscular Adipose Tissue (IMAT) and muscle Cross Sectional Area (CSA).Positive correlations between 1RM and ASMMI (rs = 0.64, P < .0001) and thigh CSA (rs = 0.52, P = .0017), but not with thigh IMAT, were found. In addition, significant correlations between knee extensors strength and ASMMI (rs = 0.48, P = .004) and thigh CSA (rs = 0.49, P = .0033) and IMAT (rs = -0.35, P = .043) were observed, whereas no significant correlations between the Mini-BESTest with ASMMI, thigh CSA, and IMAT were observed.Lower limb strength positively correlated with appendicular muscle mass. Further, the maximal isometric strength of knee extensors negatively correlated with thigh IMAT in elderly patients, whereas the dynamic balance ability did not correlate with any of the morphological variables of the muscle (i.e., ASMMI, CSA, and IMAT). A reduced muscle size and strength could affect movement and reduce physical function in older patients. Improving the composition and size of muscle in elder subjects could reduce frailty and risk of falls.

Loaded Functional Strength Training versus Traditional Physical Therapy on Hip and Knee Extensors Strength and Function Walking Capacity in Children with Hemiplegic Cerebral Palsy: Randomized Comparative Study.

Objective: This study’s objective was to see how loaded functional strengthening exercises using a plantigrade foot position and a shoe supporter affected muscle strength and walking ability in spastic hemiplegic children. Methods: Seventy-two children with spastic hemiplegic cerebral palsy, both sexes, aged ten to twelve years, were randomly assigned into two groups equal in number (control and intervention groups). The control group received a specially designed physical therapy program, whereas the intervention group received a loaded functional strengthening exercises program using a shoe supporter to maintain a plantigrade foot position. The training program was carried out for 60 min, three times per week for three consecutive months. All participants were evaluated both before and after the therapy program by using a Medical Commander Echo Manual Muscle Tester dynamometer to assess isometric muscle power of hip and knee extensors on the affected side. To assess functional walking capacity, a 6 min walking (6MWT) test was used. Results: Study groups were comparable with respect to all outcome measures at entry (p > 0.05). Within-group comparison showed significant improvements in all measured variables. Furthermore, between-group comparison revealed significantly greater improvements (p < 0.05) in hip and knee extensors strength as well as the functional walking capacity in favor of the intervention group. Conclusions: In all the analyzed variables, loaded functional strength exercises from the plantigrade foot position were found to be considerably more effective in the intervention group than in the control group.

Running interval training combined with blood flow restriction increases maximal running performance and muscular fitness in male runners

We investigated the effects of 8 weeks (3 days per week) of running interval training (RIT) combined with blood flow restriction (RIT-BFR) on the maximal running performance (RPmax), isokinetic muscle strength, and muscle endurance in athletes. Twenty endurance-trained male runners were pair-matched and randomly assigned to the RIT-BFR and RIT groups. The RIT-BFR group performed RIT (50% heart rate reserve, 5 sets of 3 min each, and 1-min rest interval) with inflatable cuffs (1.3× resting systolic blood pressure), and the RIT group performed the same RIT without inflatable cuffs. RPmax, isokinetic muscle strength, and muscle endurance were assessed at pre-, mid-, and post-training. Compared with the RIT group, the RIT-BFR group exhibited a significantly (p < 0.05) greater increase in RPmax, isokinetic knee extensor and flexor strength, and knee extensor endurance after 24 training sessions. These results suggested that RIT-BFR may be a feasible training strategy for improving muscular fitness and endurance running performance in distance runners.

762 FOR OLDER PATIENTS WITH FRAILTY, SIX WEEKS OF ENFORCED IMMOBILITY HAS NO DETRIMENTAL IMPACT ON MUSCLE STRENGTH OR THICKNESS

Abstract Introduction Immobility can lead to rapid reductions in muscle size, strength and function. Understanding these changes could inform interventions to prevent or slow decline. This longitudinal study aimed to assess the extent of muscle changes in older patients admitted with fragility fractures where clinical management was immobilisation (non-weight bearing) of the affected limb for at least 6 weeks. Method Handgrip strength (HGS); knee extensor strength(KES); Vastus Lateralis thickness and cross-sectional area at ultrasound (VLMT, VLCSA); and skeletal mass index (SMI; bioimpedance analysis) were measured in the non-injured limb of 50 patients (88% female) aged ≥70. Pre-existing physical frailty meant patients were limited to transfers only while non-weight bearing. Measurements were performed at hospital admission, 1, 3 and 6 weeks. One-way repeated measures ANOVA was used to assess changes in measurements over time. Additionally, baseline measurements in female patients (n = 36) were compared to 11 healthy, non-frail, non-hospitalised females with comparable BMI, aged ≥70, using independent t-tests. Data are mean + SD. Results Patient Clinical Frailty Score (median, IQR) was 5 (4–6). At hospital admission, female patients were older (84 ± 7 years vs. 77 ± 6 years, p &amp;lt; 0.05), weaker (HGS of 9.2 ± 4.7 kg vs. 19.9 ± 5.8 kg, p &amp;lt; 0.001; KES 4.5 ± 1.5 kg vs. 7.8 ± 1.3 kg, p &amp;lt; 0.001) and had lower VLMT (1.38 ± 0.47 cm vs. 1.75 ± 0.30 cm, p = 0.02) than non-frail female controls. Six weeks immobility had no temporal effect on any variable: HGS (F(2,51) = 1.04,p = 0.38,n = 27), KES (F(3,45) = 3.22,p = 0.81,n = 16), VLMT (F(3,54) = 2.52,p = 0.07,n = 19), VLCSA (F(3,42) = 0.74,p = 0.53,n = 15) and SMI (F(2,59) = 0.09,p = 0.94,n = 26). Conclusion Older patients admitted with fragility fractures were weaker and had lower VLMT compared to healthy, non-frail older people. This, together with the lack of decline in muscle strength and thickness with 6 weeks immobility strongly suggests muscle resilience was attenuated pre-admission, such that immobility had no further detrimental effect. These results differ from muscle changes seen in younger and non-frail cohorts, and warrants assessment of clinical interventions aimed at increasing muscle mass and function specifically in older people with frailty.

The sit-to-stand test as a patient-centered functional outcome for critical care research: a pooled analysis of five international rehabilitation studies

BackgroundWith ICU mortality rates decreasing, it is increasingly important to identify interventions to minimize functional impairments and improve outcomes for survivors. Simultaneously, we must identify robust patient-centered functional outcomes for our trials. Our objective was to investigate the clinimetric properties of a progression of three outcome measures, from strength to function.MethodsAdults (≥ 18 years) enrolled in five international ICU rehabilitation studies. Participants required ICU admission were mechanically ventilated and previously independent. Outcomes included two components of the Physical Function in ICU Test-scored (PFIT-s): knee extensor strength and assistance required to move from sit to stand (STS); the 30-s STS (30 s STS) test was the third outcome. We analyzed survivors at ICU and hospital discharge. We report participant demographics, baseline characteristics, and outcome data using descriptive statistics. Floor effects represented ≥ 15% of participants with minimum score and ceiling effects ≥ 15% with maximum score. We calculated the overall group difference score (hospital discharge score minus ICU discharge) for participants with paired assessments.ResultsOf 451 participants, most were male (n = 278, 61.6%) with a median age between 60 and 66 years, a mean APACHE II score between 19 and 24, a median duration of mechanical ventilation between 4 and 8 days, ICU length of stay (LOS) between 7 and 11 days, and hospital LOS between 22 and 31 days. For knee extension, we observed a ceiling effect in 48.5% (160/330) of participants at ICU discharge and in 74.7% (115/154) at hospital discharge; the median [1st, 3rd quartile] PFIT-s difference score (n = 139) was 0 [0,1] (p < 0.05). For STS assistance, we observed a ceiling effect in 45.9% (150/327) at ICU discharge and in 77.5% (79/102) at hospital discharge; the median PFIT-s difference score (n = 87) was 1 [0, 2] (p < 0.05). For 30 s STS, we observed a floor effect in 15.0% (12/80) at ICU discharge but did not observe a floor or ceiling effect at hospital discharge. The median 30 s STS difference score (n = 54) was 3 [1, 6] (p < 0.05).ConclusionAmong three progressive outcome measures evaluated in this study, the 30 s STS test appears to have the most favorable clinimetric properties to assess function at ICU and hospital discharge in moderate to severely ill participants.