Maximal Knee Extension Strength Research Articles

Web-Based Exercise and Nutrition Intervention to Improve Leg Muscle Strength and Physical Functioning in Older Adults: Pre-Post Pilot Study.

The lifestyle intervention ProMuscle, which combines resistance exercise and an increased protein intake, was effective in improving muscle strength, muscle mass, and physical functioning in older adults. However, due to a growing shortage of health care professionals, the rapidly growing aging population cannot be personally guided in the future. Therefore, Uni2Move, a scalable web-based variant of ProMuscle, was designed to reach larger groups of older adults without putting additional burden on health care professionals. The current study investigated the effects of a web-based lifestyle intervention on muscle strength, protein intake, and physical functioning in healthy older adults. In addition, we conducted a qualitative study to gather key insights of the participants involved, as little is known about older adults' perceptions of web-based lifestyle interventions. A pre-post pilot study was conducted in the Netherlands. In the 24-week intervention, 19 healthy adults aged >55 years were included. They performed resistance training at home twice a week for 24 weeks via web-based workout videos. Videos (45-60 minutes) were recorded by the fitness trainer and mainly focused on training leg muscles. In addition, older adults were advised on increasing protein intake via two web-based consultations by a dietitian in the first 12 weeks and via an e-learning course in the second 12 weeks. Intervention adherence and acceptance was measured in week 25. The 1 repetition maximum knee extension strength, repeated chair rise test, and protein intake were measured at baseline, week 13, and week 25. Linear mixed models were used to test differences over time. Semistructured interviews were used to gather experiences of participants. Atlas.ti version 22 was used to analyze the interviews. The mean age of participants (n=19) at baseline was 69 (SD 7) years. The 1 repetition maximum knee extension strength and repeated chair rise test improved significantly during the 24-week intervention with a mean difference of 7.0 kg (95% CI 4.8-9.3; P<.001) and -1.2 seconds (95% CI -1.7 to -0.6; P<.001), respectively. Total protein intake per day did not change, whereas protein intake during breakfast had increased significantly after 13 weeks with a mean difference of 6.9 g (95% CI 1.1-12.7; P=.01). Qualitative research revealed that advantages of the program included no need to travel and exercising in their own environment. Disadvantages were the lack of physical interaction and no corrections by the trainer. The results of the web-based exercise and nutrition intervention Uni2Move indicate potential improvements of muscle strength and physical functioning in healthy middle-aged and older adults. Providing such lifestyle interventions on the internet could reach an increased number of older adults, providing the opportunity to contribute to the health and independence of the rapidly growing aging population.

Intramuscular fatty infiltration and its correlation with muscle composition and function in hip osteoarthritis

BackgroundHip osteoarthritis patients display higher levels of fatty infiltration (FI) in the gluteus minimus (GM) compared to other hip muscles. We investigated specific histological factors such as fiber type composition and collagen deposition, and functional outcomes like muscle strength and activation associated with FI in these patients.MethodsIn twelve men (67 ± 6 y) undergoing total hip replacement (THR), hip and knee muscle strength and activation (electromyography, EMG) were assessed bilaterally. Magnetic resonance imaging (MRI) was used to compare the relative FI area and muscle cross sectional area (CSA) of the GM, rectus femoris (RF), tensor fascia latae (TFL) and vastus lateralis (VL). Adipocyte content, fiber type composition, grouping, fiber size, centrally nucleated fiber frequency, collagen deposition, satellite cell density and capillarization were assessed in intraoperative biopsies of the four muscles. Differences between GM and other muscles were assessed with repeated-measures one-way ANOVA followed by Dunnett’s post-hoc test. Pearson coefficients were calculated for the correlations between FI measurements and the other histological and functional parameters.ResultsStrength was lower in the affected limb. Knee extensor weakness was accompanied by lower VL muscle activation. Muscle CSA and FI did not differ between sides. In the affected limb, GM displayed larger relative FI area (MRI) compared to RF and VL. Biopsy adipocyte content was higher in GM than RF and TFL. Compared to the other hip muscles, GM displayed higher type 1 fiber content while its type 2X fiber content was lower. Fiber grouping levels were higher in GM than the other muscles. Collagen content was higher in GM than TFL and VL. FI in GM was associated with type 1 (r = 0.43) and type 2X (r = -0.34) fiber content, fiber grouping (r = 0.39), and collagen deposition (r = 0.37). FI in VL was negatively associated with maximal knee extension strength (r = -0.65).ConclusionsIn patients undergoing THR, the higher FI levels of GM compared to other hip muscles were associated with fiber type composition and grouping, and with higher collagen deposition. Experimental studies exploring these associations could potentially uncover new targets for the treatment of intramuscular FI and related impairments in muscle function.Trial registrationKEK number: 2016–01852, date of registration: 12-4-2017.

Improving the neuromuscular fitness of patients with type 2 diabetes by aquatic exercise training - The Diabetes and Aquatic Training Study (DATS 3): a randomized controlled trial.

To compare the effects of aquatic aerobic and combined training on neuromuscular outcomes in patients with type 2 diabetes. Patients with type 2 diabetes were randomized to an aerobic aquatic training (AERO), a combined aquatic training (COMBI) or a procedure control (CON) three weekly for 15 weeks. The sessions were 50 minutes long. Maximal strength and muscle endurance were assessed by the 1RM and maximum repetitions at 60% 1RM tests, respectively, in knee extension and elbow flexion exercises. Timed up and go test, testosterone, cortisol and testosterone:cortisol ratio also were evaluated. Participants had 59.0±8.2 years, 51% women. All groups increased (P<0.001) the maximal knee extension strength (Mean Difference: AERO: 21.1 kg; COMBI: 14.6 kg; CON: 4.4 kg), while only COMBI group increased (P<0.001) the maximal elbow flexion strength (Mean Difference: 2.6 kg). Muscle endurance in both exercises were increased in all groups. The Timed Up and Go test at the usual and maximal speed decreased in all groups. Testosterone were not modified in present study, while cortisol and testosterone:cortisol were improved in COMBI group. Aquatic training, especially combined aquatic training, improve the neuromuscular fitness of patients with type 2 diabetes.

Resistance training in women with myotonic dystrophy type 1: a multisystemic therapeutic avenue

Myotonic dystrophy type 1 (DM1) is a hereditary disease characterized by muscular impairments. Fundamental and clinical positive effects of strength training have been reported in men with DM1, but its impact on women remains unknown. We evaluated the effects of a 12-week supervised strength training on physical and neuropsychiatric health. Women with DM1 performed a twice-weekly supervised resistance training program (3 series of 6–8 repetitions of squat, leg press, plantar flexion, knee extension, and hip abduction). Lower limb muscle strength, physical function, apathy, anxiety and depression, fatigue and excessive somnolence, pain, and patient-reported outcomes were assessed before and after the intervention, as well as three and six months after completion of the training program. Muscle biopsies of the vastus lateralis were also taken before and after the training program to assess muscle fiber growth. Eleven participants completed the program (attendance: 98.5 %). Maximal hip and knee extension strength (p < 0.006), all One-Repetition Maximum strength measures (p < 0.001), apathy (p = 0.0005), depression (p = 0.02), pain interference (p = 0.01) and perception of the lower limb function (p = 0.003) were significantly improved by training. Some of these gains were maintained up to six months after the training program. Strength training is a good therapeutic strategy for women with DM1.

Specific collagen peptides increase adaptions of patellar tendon morphology following 14-weeks of high-load resistance training: A randomized-controlled trial

ABSTRACT The purpose of this study was to investigate the effect of a supplementation with specific collagen peptides (SCP) combined with resistance training (RT) on changes in structural properties of the patellar tendon. Furthermore, tendon stiffness as well as maximal voluntary knee extension strength and cross-sectional area (CSA) of the rectus femoris muscle were assessed. In a randomized, placebo-controlled study, 50 healthy, moderately active male participants completed a 14-week resistance training program with three weekly sessions (70–85% of 1 repetition maximum [1RM]) for the knee extensors. While the SCP group received 5g of specific collagen peptides daily, the other group received the same amount of a placebo (PLA) supplement. The SCP supplementation led to a significant greater (p < 0.05) increase in patellar tendon CSA compared with the PLA group at 60% and 70% of the patellar tendon length starting from the proximal insertion. Both groups increased tendon stiffness (p < 0.01), muscle CSA (p < 0.05) and muscular strength (p < 0.001) throughout the intervention without significant differences between the groups. The current study shows that in healthy, moderately active men, supplementation of SCP in combination with RT leads to greater increase in patellar tendon CSA than RT alone. Since underlying mechanisms of tendon hypertrophy are currently unknown, further studies should investigate potential mechanisms causing the increased morphology adaptions following SCP supplementation. Trial registration: German Clinical Trials Register identifier: DRKS00029244..

Effect of quadriceps training at different levels of blood flow restriction on quadriceps strength and thickness in the mid-term postoperative period after anterior cruciate ligament reconstruction: a randomized controlled external pilot study

BackgroundMore than 2 million anterior cruciate ligament (ACL) injuries occur worldwide each year. Most surgeons suggest that athletes and active persons with significant knee functional demands, including cutting motions, require and should be offered ligament reconstruction surgery. Despite concentrated rehabilitation efforts, deficits in quadriceps size and strength can persist for years after surgery. Blood flow restriction (BFR) training can help overcome disuse muscular atrophy in the mid-term postoperative period after anterior cruciate ligament reconstruction (ACLR) surgery. The purpose of this study was to evaluate the effects of quadriceps training with different levels of blood flow restriction on quadriceps strength and thickness of participants after ACLR.MethodsIn this study, 30 post-ACL reconstruction participants were randomly divided into three groups (control, 40% Arterial Occlusion Pressure [AOP] and 80% AOP groups). All patients were subjected to different levels of BFR, combined with conventional quadriceps rehabilitation, for 8 weeks. Assessments included scaled maximal isokinetic knee extension strength at 60°/s and 180°/s, the sum of the thickness of the affected femoris rectus and vastus intermedius, Y-balance test performance, and International Knee Documentation Committee questionnaire responses before and after the intervention.ResultsIn total, 23 participants completed the entire study. The 80% AOP compression group showed an increase in quadriceps femoris muscle strength and muscle thickness (p < 0.01). As compared with the control group, outcome indicators in the 40% AOP and 80% AOP group were improved (p < 0.05). After 8 weeks of experimental BFR intervention, the results were better for the 80% AOP compression group than for the 40% AOP compression group in quadriceps peak torque to body weight at 60°/s and 180°/s angular velocity, as well as the sum of the thickness of the rectus femoris and vastus intermedius.ConclusionThe combination of BFR and low-intensity quadriceps femoris training can effectively improve the muscle strength and thickness of knee extensors in participants with ACLR and help reduce the difference between the healthy and surgical sides of the knee joint while improving knee-joint function. Choosing quadriceps training with 80% AOP compression intensity could provide the most benefits. Meanwhile, BFR can accelerate the rehabilitation process of patients and allow early entry into the next rehabilitation cycle.RegistrationTrial registration Chinese Clinical Trial Registry, registration number ChiCTR2100050011, date of registration: 15/08/2021.

Relationship between individual forces of each quadriceps head during low-load knee extension and cartilage thickness and knee pain in women with knee osteoarthritis

BackgroundThis study aimed to clarify the individual forces of each quadriceps head during low-load contractions and to determine the associations between individual muscle force and cartilage thickness and symptoms in female knee osteoarthritis patients. MethodsTwenty-two women with painful knee osteoarthritis and 15 asymptomatic age-matched women (control group) participated in this cross-sectional study. Maximal knee extension strength and the cross-sectional area of each quadriceps muscle were measured. Shear modulus was calculated for each muscle during 20-Nm torque production by shear-wave elastography. Muscle force index was defined as the product of the cross-sectional area and shear modulus. Medial femur cartilage thickness was measured using an ultrasound B-mode image. Knee pain during gait was evaluated using a Numerical Rating Scale. Muscle force index, cross-sectional area, and maximal knee extension strength, which were defined as muscle functions, were compared between groups using the unpaired t-test. Correlation coefficients were calculated using muscle function, cartilage thickness, or pain. FindingsMaximal strength and vastus lateralis force index were smaller in the knee osteoarthritis group than in the control group (p < 0.001 and p = 0.005, respectively). In the knee osteoarthritis group, vastus medialis and vastus lateralis force indexes were positively correlated with cartilage thickness (r = 0.57 and r = 0.45, respectively), whereas the rectus femoris force index was negatively correlated with cartilage thickness (r = −0.45). The vastus lateralis force index was negatively correlated with knee pain (ρ = −0.56). InterpretationVasti force indices were positively associated with cartilage thickness; however, rectus femoris index was negatively associated in female patients with knee osteoarthritis.

Fatigability of the knee extensors following high- and low-load resistance exercise sessions in trained men.

Fatigability after gym-based resistance exercises with high and low loads has not been well described, thus limiting the translation of exhaustive low-weight prescription into athletic practice. We compared the fatigability and recovery of the knee extensor muscles for up to 1H after sessions that involved either high- or low-load resistance exercises. 16 trained men performed two resistance exercise sessions between 5 and 7days apart. The LIGHT session involved five sets to task failure at 50% of maximal knee-extension strength, whereas the HEAVY session accrued repetitions across seven sets at intensities ≥ 80% maximal knee-extension strength. Measures of quadriceps maximal torque and rate of torque development were measured before, after, and 1H after each exercise session. Muscle activation (electromyography and voluntary activation) and contractility were measured from doublet stimulation of the femoral nerve during and after maximal contractions, respectively. Greater declines in maximal rate of torque development were observed after the LIGHT compared with the HEAVY session (p < 0.001), with full recovery after 1H. Voluntary activation (100-Hz doublet stimulation) and surface electromyograms were reduced immediately after the HEAVY session only (p < 0.05), with greater declines in quadriceps twitch amplitudes after the LIGHT session (p < 0.01). Voluntary activation (100-Hz doublet stimulation) was reduced at 1H after both the HEAVY and LIGHT sessions (p < 0.05). Despite differences in the decreases in muscle activation and contractility after high- and low-load resistance-exercise sessions, recovery of neuromuscular function was essentially complete after 1H of rest for both sessions.

Anterior Cruciate Ligament Reconstruction Using Autologous Hamstrings Augmented With the Ligament Augmentation and Reconstruction System Versus Hamstrings Alone: A Comparative Cohort Study.

Background:Few studies have reported the return-to-sports (RTS) rate in patients after augmentation of autologous anterior cruciate ligament reconstruction (ACLR) with the Ligament Augmentation and Reconstruction System (LARS).Purpose/Hypothesis:The purpose of this study was to compare postoperative outcomes in patients who underwent ACLR with single-bundle 4-strand hamstring autograft either without augmentation (HA-ACLR group) or with LARS augmentation (AUG-ACLR group). It was hypothesized that clinical outcomes and RTS rates would be better in the AUG-ACLR group at the 1-year follow-up, with similar outcomes in both cohorts by 2 years.Study Design:Cohort study; Level of evidence, 3.Methods:Patients who underwent ACLR between April 2014 and December 2017 were included in the current comparative study if they were skeletally mature and had 1- and 2-year follow-up outcomes; patients with concomitant meniscal surgery were also included. Included were 66 patients with AUG-ACLR (mean age, 26.8 years; 67% male) and 130 patients with HA-ACLR (mean age, 27.5 years; 61% male). Subjective outcome measures included the International Knee Documentation Committee Subjective Knee Evaluation Form, Knee injury and Osteoarthritis Outcome Score, Lysholm scale, Tegner activity scale, and the Noyes sports activity rating scale. Objective measures included knee laxity, maximal isokinetic knee flexion and extension strength, and the results of 4 functional hop tests.Results:There were no significant differences between the study groups in age, sex distribution, body mass index, time to surgery, or number of concurrent meniscal surgeries. At the 1-year follow-up, the AUG-ACLR group had a significantly higher Tegner score (P = .001) and rates of RTS (P = .029) and return to preinjury level of sport (P = .003) compared with the HA-ACLR group. At the 2-year follow-up, there were no differences in these measures between groups. There were no between-group differences in other subjective outcomes, knee laxity, or strength and hop test results at either postoperative time point. There were also no differences in rerupture rates or other complications between the groups.Conclusion:Patients with AUG-ACLR had higher 1-year postoperative Tegner scores and rates of RTS and preoperative sport level compared with the HA-ACLR group. The 2-year rerupture rate for the AUG-ACLR group was low, and no intra-articular inflammatory complications were noted.

Effects of a power training program in the functional capacity, on body balance and lower limb muscle strength of elderly with type 2 diabetes mellitus.

The effects of interventions with muscle power training on balance and functionality in individuals with type 2 diabetes mellitus (T2DM) are still poorly investigated. We evaluated the efficacy of a twelve-week power training program in the functional capacity, balance and lower limb muscle power and strength of elderly with T2DM. Twenty-one subjects (14 women and seven men) were allocated into two groups. One of the groups (PTG) performed a power training program twice a week (N.=11; age 70.5±7.8 years old), and the other was an active control group (CG) that performed a weekly stretching session (N.=10; age 66±3.2 years old). Outcomes of interest were assessed at baseline and after 12 weeks, these included functional capacity, balance, muscle strength and power. The PTG participants improved their dynamic balance (P=0.027) and decrease in the time to perform the gait speed test (P<0.001), evaluated by the short physical performance battery (SPPB). Also showed a statically significant change muscle power (P=0.034) and maximal dynamic knee extension strength (P=0.023), with increments of 24% and 34%, respectively, in comparison to the CG. Both groups showed significant changes in the performance of the five-times-sit-to-stand test (P<0.001) and the SPPB score (P=0.001). The power training program was able to promote improvements in some functional parameters as on the body balance and functional capacity and muscle strength of the elderly with T2DM. The training method was effective and safe, with no adverse effects during sessions.

The Relation Between Hamstring:Quadriceps Ratio And Knee Functional Performance During Hopping Tasks

A hamstring to quadriceps strength ratio (H:Q) ≥60% and limb symmetry index (LSI) ≥90% during unilateral assessments of strength and function have been used as return to play (RTP) benchmarks following anterior cruciate ligament reconstruction (ACLR). PURPOSE: Determine the relation between H:Q and single (SH), triple (TH), triple cross-over (CH), and 6 m timed (6H) hopping assessment performance (e.g. distance achieved or time to complete). METHODS: Sixty-four ACLR patients (34 males: 20.92 ± 7.93 y, 1.83 ± .09 m, 88.34 ± 17.36 kg; 30 females: 17.63 ± 2.84 y, 1.67 ± .07 m, 63.32 ± 7.25 kg) 26.01 ± 9.57 wks post-surgery volunteered to participate. Participants completed maximal voluntary isokinetic knee extension and flexion strength testing on the injured leg (IL) and non-injured leg (NIL) through a range of 20° to 90° of knee flexion at 60°·s-1, 180°·s-1, and 300°·s-1. Participants were stratified into groups based on whether they obtained ≥60% H:Q (PASS) or <60% H:Q (FAIL) for each speed. Three trials of each hop test were performed on IL and NIL. The mean hop performance on each leg per test was normalized to participant height. Pearson correlations were used to explore the relation between hopping performance and H:Q. T-tests were used to assess for the effect of group on hopping performance. Significance was set at p < 0.05 RESULTS: Males demonstrated negative correlations for IL between SH and H:Q at 300°·s-1 (r = -.49 [-.71 -.18], p = .003), TH and H:Q at 60°·s1 (r = -.80 [-.80 to -.38], p < .001), and TH and H:Q at 180°·s-1 (r = -.63 [-.76, -.27], p < .001). Males also demonstrated negative correlations for NIL between TH and H:Q at 60°·s-1 (r = -.41 [-.65 to -.08], p = .018) and 180°·s-1 (r = -.42 [-.64, -.05], p = .027). No significant correlations between H:Q and hopping performance were identified in females. At 300°·s-1, FAIL males had greater normalized SH scores for both IL (.78 ± .18 vs. .89 ± .15; p = .04) and NIL (.82 ± .15 vs. .91 ± .14; p = .06). CONCLUSION: These results suggest a negative relation between H:Q and functional performance post-ACLR. H:Q <60% may indicate superior quadriceps strength which leads to a greater internal knee extension moment capacity and improved hopping performance. However, achieving an H:Q above an acceptable threshold may be protective and aid in knee joint translation stability.

Changes In Muscle Power After Usual Care Or Early Structured Exercise Intervention In Acutely Hospitalized Older Adults: A Secondary Analysis Of A Randomized Controlled Trial.

PURPOSE: To assess the effects of a multicomponent exercise training intervention on dynamic and isometric maximal muscle strength of lower and upper extremities and muscle power output in acutely hospitalized older adults. METHODS: A secondary analysis of a single-blind randomized clinical trial in an acute care for elderly (ACE) unit in a tertiary public hospital in Navarre (Spain). 370 hospitalized patients (aged ≥75 years) were randomly allocated to an exercise intervention (n=185) or a usual care (n=185) group. The intervention consisted of a multicomponent exercise-training program performed during 5-7 consecutive days (2 sessions/day). The usual care group received habitual hospital care, which included physical rehabilitation when needed. The main endpoints were change in maximal dynamic strength (i.e., leg-press, chest-press, and knee extension exercises) and maximal isometric knee extensors and hip flexors strength from baseline to discharge. Changes in muscle power output at submaximal and maximal loads were also measured after the intervention period. RESULTS: The physical exercise program provided significant benefits over usual care. At discharge, the exercise group showed a mean increase of 19.6 kg (95% confidence interval [CI], 16.0, 23.2; p<0.001) on the one-repetition maximum (1RM) in the leg-press exercise, 5.7 kg (95%CI, 4.7, 6.8; p<0.001) on the 1RM in the chest-press exercise, and 9.4 kg (95%CI, 7.3, 11.5; p<0.001) on the 1RM in the knee extension exercise over usual-care group. There were improvements in the intervention group also in the isometric maximal knee extension strength (14.8 Newtons (N); 95%CI, 11.2, 18.5 vs. -7.8 N; 95%CI, -11.0, -3.5 in the control group; p<0.001) and the hip flexion strength (13.6 N; 95%CI, 10.7, 16.5 vs. -7.2 N; 95%CI, -10.1, -4.3; p<0.001). Significant benefits were also observed in the exercise group for the muscle power output at submaximal loads (i.e., 30%1RM, 45%1RM, 60%1RM, and 75%1RM; all p<0.001) over usual care group. CONCLUSIONS: An individualized, multicomponent exercise-training program, with special emphasis on muscle power training, proved to be an effective therapy for improving muscle power output of lower limbs at submaximal loads and maximal muscle strength in very old patients during acute hospitalization.

Changes in muscle power after usual care or early structured exercise intervention in acutely hospitalized older adults

BackgroundA classic consequence of short‐term bed rest in older adults is the significant loss in skeletal muscle mass and muscle strength that underlies the accelerated physical performance deficits. Structured exercise programmes applied during acute hospitalization can prevent muscle function deterioration.MethodsA single‐blind randomized clinical trial conducted in an acute care for elders unit in a tertiary public hospital in Navarre (Spain). Three hundred seventy hospitalized patients [56.5% female patients; mean age (standard deviation) 87.3 (4.9) years] were randomly allocated to an exercise intervention (n = 185) or a control (n = 185) group (usual care). The intervention consisted of a multicomponent exercise training programme performed during 5–7 consecutive days (2 sessions/day). The usual‐care group received habitual hospital care, which included physical rehabilitation when needed. The main endpoints were change in maximal dynamic strength (i.e. leg‐press, chest‐press, and knee extension exercises) and maximal isometric knee extensors and hip flexors strength from baseline to discharge. Changes in muscle power output at submaximal and maximal loads were also measured after the intervention.ResultsThe physical exercise programme provided significant benefits over usual care. At discharge, the exercise group showed a mean increase of 19.6 kg [95% confidence interval (CI), 16.0, 23.2; P < 0.001] on the one‐repetition maximum (1RM) in the leg‐press exercise, 5.7 kg (95% CI, 4.7, 6.8; P < 0.001) on the 1RM in the chest‐press exercise, and 9.4 kg (95% CI, 7.3, 11.5; P < 0.001) on the 1RM in the knee extension exercise over usual‐care group. There were improvements in the intervention group also in the isometric maximal knee extension strength [14.8 Newtons (N); 95% CI, 11.2, 18.5 vs. −7.8 N; 95% CI, −11.0, −3.5 in the control group; P < 0.001] and the hip flexion strength (13.6 N; 95% CI, 10.7, 16.5 vs. −7.2 N; 95% CI, −10.1, −4.3; P < 0.001). Significant benefits were also observed in the exercise group for the muscle power output at submaximal loads (i.e. 30% 1RM, 45% 1RM, 60% 1RM, and 75% 1RM; all P < 0.001) over usual‐care group.ConclusionsAn individualized, multicomponent exercise training programme, with special emphasis on muscle power training, proved to be an effective therapy for improving muscle power output of lower limbs at submaximal loads and maximal muscle strength in older patients during acute hospitalization.

Water-based continuous and interval training in older women: Cardiorespiratory and neuromuscular outcomes (WATER study).

The purpose of this study was to investigate the effects of two water-based aerobic programs on cardiorespiratory and neuromuscular outcomes in older women. Forty-one women (60 to 75years old) volunteered to participate in the study. Participants were randomized into a water-based continuous (CTG; n=21; 63.9±2.5years) or an interval (ITG; n=20; 64.8±3.6years) aerobic training group. Both training programs were performed for 12weeks (45-min sessions twice a week), with exercise intensity based on rating of perceived exertion (Borg's RPE 6-20 Scale). Pre and post training assessments of cardiorespiratory and neuromuscular outcomes were performed. Data analyses were conducted using Generalized Estimating Equations and Bonferroni post-hoc test (α=0.05). After the intervention, the CTG and the ITG displayed similar improvements in time to exhaustion (8% vs. 11%), peak oxygen uptake (9% vs. 7%), maximal dynamic knee extension strength (5% vs. 6%), dynamic muscular endurance of knee extensors (10% vs. 11%), maximal vastus lateralis electromyographic signal amplitude (13% vs. 35%), as well as an increase in muscle thickness (5% vs. 6%) and decrease in muscle echo intensity (-2% vs. -3%) of the quadriceps femoris. In conclusion, older women benefited from water-based exercise training prescribed based on participants' RPE, with both the interval and the continuous training programs resulting in similar increases in the cardiorespiratory and neuromuscular parameters.

Comparing the Effectiveness of BloodFlow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial.

We implemented a bloodflow restriction resistance training (BFR-RT) intervention during an 8-week rehabilitation programme in anterior cruciate ligament reconstruction (ACLR) patients within a National Health Service setting. To compare the effectiveness of BFR-RT and standard-care traditional heavy-load resistance training (HL-RT) at improving skeletal muscle hypertrophy and strength, physical function, pain and effusion in ACLR patients following surgery. 28 patients scheduled for unilateral ACLR surgery with hamstring autograft were recruited for this parallel-group, two-arm, single-assessor blinded, randomised clinical trial following appropriate power analysis. Following surgery, a criteria-driven approach to rehabilitation was utilised and participants were block randomised to either HL-RT at 70% repetition maximum (1RM) (n = 14) or BFR-RT (n = 14) at 30% 1RM. Participants completed 8weeks of biweekly unilateral leg press training on both limbs, totalling 16 sessions, alongside standard hospital rehabilitation. Resistance exercise protocols were designed consistent with standard recommended protocols for each type of exercise. Scaled maximal isotonic strength (10RM), muscle morphology of the vastus lateralis of the injured limb, self-reported function, Y-balance test performance and knee joint pain, effusion and range of motion (ROM) were assessed at pre-surgery, post-surgery, mid-training and post-training. Knee joint laxity and scaled maximal isokinetic knee extension and flexion strength at 60°/s, 150°/s and 300°/s were measured at pre-surgery and post-training. Four participants were lost, with 24 participants completing the study (12 per group). There were no adverse events or differences between groups for any baseline anthropometric variable or pre- topost-surgery change in any outcome measure. Scaled 10RM strength significantly increased in the injured limb (104 ± 30% and 106 ± 43%) and non-injured limb (33 ± 13% and 39 ± 17%) with BFR-RT and HL-RT, respectively, with no group differences. Significant increases in knee extension and flexion peak torque were observed at all speeds in the non-injured limb with no group differences. Significantly greater attenuation of knee extensor peak torque loss at 150°/s and 300°/s and knee flexor torque loss at all speeds was observed with BFR-RT. No group differences in knee extensor peak torque loss were found at 60°/s. Significant and comparable increases in muscle thickness (5.8 ± 0.2% and 6.7 ± 0.3%) and pennation angle (4.1 ± 0.3% and 3.4 ± 0.1%) were observed with BFR-RT and HL-RT, respectively, with no group differences. No significant changes in fascicle length were observed. Significantly greater and clinically important increases in several measures of self-reported function (50-218 ± 48% vs. 35-152 ± 56%), Y-balance performance (18-59 ± 22% vs. 18-33 ± 19%), ROM (78 ± 22% vs. 48 ± 13%) and reductions in knee joint pain (67 ± 15% vs. 39 ± 12%) and effusion (6 ± 2% vs. 2 ± 2%) were observed with BFR-RT compared to HL-RT, respectively. BFR-RT can improve skeletal muscle hypertrophy and strength to a similar extent to HL-RT with a greater reduction in knee joint pain and effusion, leading to greater overall improvements in physical function. Therefore, BFR-RT may be more appropriate for early rehabilitation in ACLR patient populations within the National Health Service.

Minimum 10 Year Clinical and Radiological Outcomes of a Randomized Controlled Trial Evaluating Accelerated Weight Bearing After Matrix-Induced Autologous Chondrocyte Implantation

Objectives: Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging clinical outcomes in the treatment of symptomatic knee chondral defects. However, longer term results are still lacking and post-operative management has traditionally been conservative, with little available evidence on how best to progressively increase weight bearing (WB) and rehabilitation post-surgery. This study sought to investigate the longer term clinical and radiological outcomes following an accelerated (versus conservative) WB protocol after MACI. Methods: A randomized controlled study design was used to investigate outcomes in 70 patients who underwent MACI to the medial or lateral femoral condyle between November 2005 and November 2007, in conjunction with either an accelerated (AR, n=34, 8 weeks to full WB) or conservative (CR, n=36, 12 weeks to full WB) approach to post-operative WB rehabilitation. Patients were evaluated pre-surgery and at 3, 6, 12 and 24 months, as well as 5 years post-surgery. At minimum 10 year follow up (range 10.5-11.5 years), 60 patients (86%, AR=31, CR=29) were available for review. Clinical outcomes included the IKDC, KOOS, Lysholm, Cincinnati, Tegner, SF-36, Satisfaction, maximal isokinetic knee extensor and flexor strength and functional hop capacity. Limb Symmetry Indicies (LSIs) comparing the operated and non-operated limbs were calculated for strength and functional measures. High resolution magnetic resonance imaging (MRI) was undertaken to assess the quality and quantity of repair tissue as per the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system. A combined MRI composite score was also evalauted. ANOVA investigated group differecnes over time. Results: While the AR group reported significantly less knee pain in the earlier post-operative timeline, no significant differences (p&gt;0.05) were observed in patient demographics or injury/surgery characteristics between groups, nor clinical and MRI-based scores, at minimum 10 year post-operative follow up. All clinical scores across both groups significantly improved (p&lt;0.001) to 5 years, maintained to 10 years. At minimum 10 years, no differences were observed in mean LSIs for maximal isokinetic knee extension strength (AR=96.8%, CR=97.9%), or the single (AR=95.5%, CR=98.9%) and triple hop (AR=96.7%, CR=99.6%) tests for distance. At a minimum 10 years 82.4% and 83.3% of patients in the AR and CR groups, respectively, demonstrated a good-excellent MRI composite score, while 79.4% and 83.3% demonstrated good-excellent tissue infill, as per the MOCART score. Graft failure was observed on MRI in 5 patients (8.3%, AR=2, CR=3) at 10 years post-surgery. At 10 years, 93.3% of patients were satisfied with MACI for relieving their pain, with 83.4% satisfied with their ability to participate in sport. Conclusion: MACI provided high levels of patient satisfaction and tissue durability beyond 10 years. The outcomes of this randomized trial demonstrate a safe and effective accelerated WB rehabilitation protocol, with improved early patient outcomes albeit comparable longer term results.

Regional Vastus Medialis and Vastus Lateralis Activation in Females with Patellofemoral Pain.

This study aimed to investigate whether regional activation patterns in the vasti muscles differ between females with and without patellofemoral pain (PFP), and whether muscle activation patterns correlate with knee extension strength. Thirty-six females with PFP and 20 pain-free controls performed a standardized knee flexion-extension task. The activation of vastus medialis (VM) and vastus lateralis (VL) was collected using high-density surface EMG and analyzed using principal component (PC) analysis. Spatial locations and temporal coefficients of the PC, and the percent variance they explain, were compared between groups and between the concentric and the eccentric phases of the movement. Correlations were assessed between PC features and knee extension strength. The spatial weights of PC1 (general vasti activation) and PC2 (reflecting vastus-specific activation) were similar between groups (R > 0.95). Activation patterns in PFP were less complex than controls. Fewer PC features were necessary to reconstruct 90% of the signal for PFP participants in the concentric phase (P < 0.05), and the difference in bias of activation to VM (concentric phase) or VL (eccentric phase) was less between phases for PFP participants (P < 0.05). Smaller difference in vastus-specific activation in concentric and eccentric phases (less task specificity of VM/VL coordination) was related to greater maximal knee extension strength (P < 0.05, R < -0.43). These data suggest PFP involves a simpler control strategy of VM and VL. The inverse association between task specificity and maximal knee extension strength suggests different presentations of PFP: lower knee extension strength but VM/VL coordination task specificity comparable with controls, or knee extension strength comparable with controls but lower VM/VL coordination task specificity.

Accelerometer-Determined Intensity and Duration of Habitual Physical Activity and Walking Performance in Well-Functioning Middle-Aged and Older Women: A Cross-Sectional Study.

The association of physical activity (PA) intensities and duration spent in those activities with different walking tasks remains unclear. To examine the association between the duration of PA intensities and three walking speeds (usual walking speed, maximal walking speed and zig-zag walking speed). Multiple linear regression analysis was used to estimate the association of age, BMI, maximum knee extension strength, light PA, moderate PA and vigorous PA with walking speeds. University lab. Eighty-six older women (67 ± 7 years). PA was measured for 30 consecutive days using the Lifecorder-EX accelerometer. Exercise intensity was categorized as light (levels 1-3), moderate (levels 4-6) and vigorous (levels 7-9) based on the manufacturer algorithms. Usual straight walking speed (20 m), maximal straight walking speed (20 m) and zig-zag walking speed tests (10 m) were performed by each participant. For the usual straight walking speed model (R2 = 0.296, SEE = 0.15 m/s), the significant predictors were BMI, knee extension strength, light PA and vigorous PA. For the maximal straight walking speed model (R2 = 0.326, SEE = 0.20 m/s), only age was a significant predictor. For the zig-zag walking speed model (R2=0.417, SEE = 0.14 m/s), age and maximum knee strength were significant predictors in the model. Overall, the results of this study suggest that vigorous PA and maximal knee extension strength are two important factors that are associated with different walking speeds in older women.

Physical performance in relation to menopause status and physical activity.

The aim of this study was to examine differences in physical performance (muscle power, muscle strength, aerobic capacity, and walking speed) across menopausal stages and potential of leisure physical activity (PA) to modify the impact of menopause on physical performance. In this cross-sectional study, women aged 47 to 55 were randomly selected from the Finnish National Registry and categorized as premenopausal (n = 233), perimenopausal (n = 381), or postmenopausal (n = 299) based on serum concentrations of follicle-stimulating hormone and bleeding diary. Physical performance was measured by knee extension force, handgrip force, vertical jumping height, maximal walking speed, and 6-minute walking distance. PA level was assessed by self-report and categorized as low, moderate, or high. Multivariate linear regression modeling was used for data analysis. After including fat mass, height, PA, and education in the model, the postmenopausal women showed 12.0 N weaker (P < 0.001) handgrip force and 1.1 cm lower (P < 0.001) vertical jumping height than the premenopausal women. There was no significant interaction between menopausal stage and PA on physical performance. The peri- and postmenopausal women with a high PA, however, showed better performance in the maximal knee extension strength and 6-minute walking test, and showed greater lower body muscle power than those with a low PA. Menopause status is associated with muscle strength and power, whereas the association between menopause status and mobility/walking is clearly weaker. A high leisure PA level provides more capacity to counteract the potential negative influence of menopausal factors on muscle function.

Changes of Maximum Leg Strength Indices During Adulthood a Cross-Sectional Study With Non-athletic Men Aged 19-91.

Age-related loss of muscle mass and function, also called sarcopenia, was recently added to the ICD-10 as an independent condition. However, declines in muscle mass and function are inevitable during the adulthood aging process. Concerning muscle strength as a crucial aspect of muscle function, maximum knee extension strength might be the most important physical parameter for independent living in the community. In this study, we aimed to determine the age-related decline in maximum isokinetic knee extension (MIES) and flexion strength (MIFS) in adult men. The primary study hypothesis was that there is a slight gradual decrease of MIES up to ≈age 60 years with a significant acceleration of decline after this “changepoint.” We used a closed kinetic chain system (leg-press), which is seen as providing functionally more relevant results on maximum strength, to determine changes in maximum isokinetic hip/leg extensor (MIES) and flexor strength (MIFS) during adulthood in men. Apart from average annual changes, we aimed to identify whether the decline in maximum lower extremity strength is linear. MIES and MIFS data determined by an isokinetic leg-press of 362 non-athletic, healthy, and community-dwelling men 19–91 years old were included in the analysis. A changepoint analysis was conducted based on a multiple regression analysis adjusted for selected co-variables that might confound the proper relationship between age and maximum strength. In summary, maximum isokinetic leg-strength decline during adulthood averaged around 0.8–1.0% p.a.; however, the reduction was far from linear. MIES demonstrated a non-significant reduction of 5.2 N/p.a. (≈0.15% p.a.) up to the estimated breakpoint of 52.0 years and an accelerated loss of 44.0 N/p.a. (≈1.3% p.a.; p < 0.001). In parallel, the decline in MIFS (10.0 N/p.a.; ≈0.5% p.a.) prior to the breakpoint at age 59.0 years was significantly more pronounced. Nevertheless, we observed a further marked accelerated loss of MIFS (25.0 N/p.a.; ≈1.3% p.a.) in men ≥60 years. Apart from the “normative value” and closed kinetic chain aspect of this study, the practical application of our results suggests that sarcopenia prophylaxis in men should be started in the 5th decade in order to address the accelerated muscle decline of advanced age.