Extensor Function Research Articles

The Effect of Isometric Exercise Position on the Effectiveness of Isolated Work of the Thigh Flexor Muscles Based on the Results of the sEMG Study.

The main function of the hamstring muscles is to bend the knee joint and support the function of the hip extensors. Their frequent injuries are the result of overload related to, among others, dynamic running or jumping, and inadequate preparation for athletics activities. The asymmetry of the work of individual flexor muscle groups is clearly marked in the case of valgus or varus of the knee joint, i.e., in different positions of the lower limb. The aim of the study was to determine the position and form of a rehabilitation exercise in which an isolated group of muscles flexing the knee joint will show the greatest bioelectrical activity. The study involved 25 students of the Jagiellonian University Medical College. The students were aged 20-26. The average age was 22.9 (±1.4). The study participants included 17 women with an average age of 23.0 (±1.1) and 8 men with an average age of 22.6 (±1.9). Women constituted 68% and men 32% of all respondents. All participants agreed to participate in the study. Surface electromyography measurements in both lower limbs provided an initial number of 50 cases. The activity of the knee flexor muscles during isometric contraction with resistance was measured in correlation with three foot and lower leg settings: internal rotation, neutral position, and external rotation. The bioelectrical activity of the semitendinosus muscle is significantly higher (p < 0.01) in the internal rotation position than in the neutral position of the lower leg, while the bioelectrical activity of the biceps femoris muscle is inversely higher (p < 0.01) in the external rotation position than in the neutral position. The results are significant for both average and maximum values of muscle stimulation. During isometric contraction with resistance, the semitendinosus muscle shows the greatest bioelectrical activity in the internal rotation position of the lower leg and foot, and the biceps femoris muscle in the external rotation position of the lower leg and foot. The above information has important implicational applications when improving isolated groups of hamstrings. In the future, this may contribute to more effective rehabilitation of patients with injuries of the muscles described in the article.

Efficacy of self-care foam rolling intervention on muscle function and pain conducted by postoperative patients who underwent total knee arthroplasty from the second to the third postoperative week

BackgroundThis study aimed to investigate whether self-care foam rolling (FR) intervention, in addition to regular physical therapy, effectively improves pain, knee joint range of motion (ROM), muscle function (knee extension strength and gait speed), and balance function in patients who underwent total knee arthroplasty (TKA) during the second and third postoperative weeks. MethodsA total of 15 patients admitted to the hospital and who underwent TKA for knee osteoarthritis were enrolled. FR was performed for more than 10 min in the morning and 10 min in the afternoon each day from the second to the third postoperative week. Knee flexion and extension ROM, pain (resting and stretching position), 10 m walk speed, timed up-and-go test (TUG), one-leg stand, and maximal voluntary isometric contraction torques of knee extensors were assessed. ResultsSignificant improvements in knee flexion pain, knee flexion ROM, knee extension ROM, knee extension strength, 10 m walk speed, TUG, and one-leg stand were observed from the second to the third postoperative week. However, at rest, no statistically significant differences in pain were found. ConclusionsMuscle function of the knee extensors improved following the self-care FR intervention probably attributed to the adjusted pain level.

Effect of open vs. closed kinetic chain exercises in ACL rehabilitation on knee joint pain, laxity, extensor muscles strength, and function: a systematic review with meta-analysis.

PROSPERO [CRD42023475230].

Using Free Chimeric Anterolateral Thigh Flap For Reconstruction Of Composite Dorsal Hand Defect

Simultaneous repair of the extensor tendons and soft tissues in hand injuries remains challenging. The free chimeric anterolateral thigh (ALT) flap with fascia lata (FL) flap represents an alternative for hand reconstruction. This report describes the reconstruction of the extensor tendon and skin defects using free chimeric ALT flaps with FL. Eight patients (one female and seven male) underwent reconstruction of complex hand defects with free chimeric ALT and FL flaps. The defects were caused by crushing injuries, burns, snakebite scars, and animal bite wounds. The average skin defect was 116 cm2. Perforators were selected for the skin paddle and the FL flap. The thinning procedure was performed microsurgically. The skin paddle size ranged from 12 to 23cm in length and 6 to 11cm in width, and the FL flaps ranged from 3×5 to 12×5cm. The mean pedicle length was 7.88cm. Nine extensor tendons were repaired with FL flaps. The flap thickness after thinning was only 3-6mm. The donor site was closed primarily in six patients, and skin grafts were used in two cases. All flaps survived without complications. The follow-up period lasted from 17 to 80 months. Range of motion was achieved with satisfaction. The chimeric-thinned ALT and FL flap is a valuable material, and it should be considered a reconstructive option for hand soft tissue and extensor tendon reconstruction. This technique allows us to achieve a good appearance and extensor function without donor-site morbidity.

Acute effects of isotonic eccentric exercise on the neuromuscular function of knee extensors vary according to the motor task: impact on muscle strength profiles, proprioception and balance.

Eccentric exercise has often been reported to result in muscle damage, limiting the muscle potential to produce force. However, understanding whether these adverse consequences extend to a broader, functional level is of apparently less concern. In this study, we address this issue by investigating the acute and delayed effects of supramaximal isotonic eccentric exercise on neuromuscular function and motor performance of knee extensors during tasks involving a range of strength profiles, proprioception, and balance. Fifteen healthy volunteers (23.2 ± 2.9 years old) performed a unilateral isotonic eccentric exercise of the knee extensors of their dominant lower limb (4 × 10 reps at 120% of one Repetition Maximum (1RM)). The maximum voluntary isometric contraction (MVC), rate of force development (RFD), force steadiness of the knee extensors, as well as knee joint position sense and mediolateral (MLI) and anteroposterior stability (API) of the dominant lower limb, were measured pre-, immediately, and 24 h after the eccentric exercise. The EMG amplitude of the vastus medialis (VM) and biceps femoris (BF) were concomitantly evaluated. MVC decreased by 17.9% immediately after exercise (P < 0.001) and remained reduced by 13.6% 24 h following exercise (P < 0.001). Maximum RFD decreased by 20.4% immediately after exercise (P < 0.001) and remained reduced by 15.5% at 24 h (P < 0.001). During the MVC, EMG amplitude of the VM increased immediately after exercise while decreasing during the RFD task. Both values returned to baseline 24 h after exercise. Compared to baseline, force steadiness during submaximal isometric tasks reduced immediately after exercise, and it was accompanied by an increase in the EMG amplitude of the VM. MLI and knee joint position sense were impaired immediately after isotonic eccentric exercise (P < 0.05). While MLI returned to baseline values 24 h later, the absolute error in the knee repositioning task did not. Impairments in force production tasks, particularly during fast contractions and in the knee joint position sense, persisted 24 h after maximal isotonic eccentric training, revealing that neuromuscular functional outputs were affected by muscle fatigue and muscle damage. Conversely, force fluctuation and stability during the balance tasks were only affected by muscle fatigue since fully recovered was observed 24 h following isotonic eccentric exercise.

Maintenance of internal load despite a stepwise reduction in external load during moderate intensity heart rate clamped cycling with acute graded normobaric hypoxia in males

ObjectivesTo investigate the acute effects of graded hypoxia on external and internal loads during 60 min of endurance cycling at a clamped heart rate. DesignRepeated measures. MethodsOn separate visits, 16 trained males cycled for 60 min at a clamped heart rate corresponding to 80 % of their first ventilatory threshold at sea-level and 2500 m, 3000 m, 3500 m and 4000 m simulated altitudes (inspired oxygen fractions of 20.9 %, 15.4 %, 14.5 %, 13.6 % and 12.7 %, respectively). Markers of external (power output) and internal (blood lactate concentration, tissue saturation index, cardio-respiratory and perceptual responses) loads were measured every 15 min during cycling. Neuromuscular function of knee extensors was characterised pre- and post-exercise. ResultsCompared to sea-level (101 ± 22 W), there was a stepwise reduction in power output with increasing hypoxia severity (−17.9 ± 8.9 %, −27.1 ± 10.7 %, −34.2 ± 12.0 % and − 44.6 ± 15.1 % at 2500 m, 3000 m, 3500 m, and 4000 m, respectively, all p < 0.05). Blood lactate and tissue saturation index were not different across hypoxia severities, and perceptual responses were exacerbated at 4000 m only, with increased breathing difficulty. Knee extensor torque decreased post-exercise (−14.5 ± 9.0 %, p < 0.05), independent of condition. ConclusionsIncreasing hypoxia severity reduces cycling power output and arterial oxygen saturation in a stepwise fashion without affecting exercise responses between sea-level and simulated altitudes up to 3500 m despite breathing difficulty being elevated at 4000 m.

Lower Body Joint Moments during the Golf Swing in Older Adults: Comparison to Other Activities of Daily Living.

Golf participation has increased dramatically in the last several years. With this increase in participation, clinicians need better evidenced based strategies to advise those golfers with different pathologies when it is safe to return to the game. Golf teaching professionals also need to understand how to alter golf mechanics to protect injured and/or diseased joints in golfers to allow them to play pain free and avoid further injury. This study used a 3-dimensional link segment model to calculate the net joint moments on the large lower limb joints (knee and hip) during golf (lead and trail leg) and two commonly studied activities of daily living (gait and sit-to-stand) in 22 males, healthy, adult golfers. It also examined the correlations between these knee and hip joint loads and club head speed. The external valgus knee moment and the internal hip adduction moment were greater in the lead leg in golf than in the other activities and were also correlated with club head speed. This indicates a strategy of using the frontal plane GRF moment during the swing. The internal hip extension and knee flexion moment were also greater in the golf swing as compared with the other activities and the hip extension moment was also correlated with club head speed. This emphasizes the importance of hip extensor (i.e., gluteus maximus and hamstring) muscle function in golfers, especially in those emphasizing the use of anterior-posterior ground reaction forces (i.e., the pivoting moment). The golf swing places some loads on the knee and the hip that are much different than the loads during gait and sit-to-stand tasks. Knowledge of these golf swing loads can help both the clinician and golf professional provide better evidence-based advice to golfers in order to keep them healthy and avoid future pain/injury.

PATELLA FRACTURES, EPIDEMIOLOGY, ANATOMY, FUNCTION, MECHANISMS OF ACTION, CLASSIFICATION, CLINICAL PRESENTATION, IMAGING PRESENTATION, TREATMENT AND COMPLICATIONS

Introduction: The patella has a great importance in the extension and flexion activities of the knee, being paramount in the patient's quality of life. Nowadays the surgical options that stand out the most are open reduction plus internal fixation and resection of the patella. The patella increases the leverage of the quadriceps. Management following patella injury has been based on preservation of bone and vascular supply, in addition to joint restoration and extensor function. In patella fractures, it is essential to reflect on the biomechanics of the bone and the fixation technique to be used. Objective: to detail the current information related to patella fractures, epidemiology, anatomy, function, mechanisms of action, classification, clinical presentation, imaging presentation, treatment and complications. Methodology: a total of 32 articles were analyzed in this review, including review and original articles, as well as clinical cases, of which 24 bibliographies were used because the other articles were not relevant for this study. The sources of information were PubMed, Google Scholar and Cochrane; the terms used to search for information in Spanish, Portuguese and English were: patella, patellar fractures, knee trauma. Results: Patellar fractures comprise 1% of all fractures in humans, with a 2:1 male to female ratio. They occur more frequently in individuals between 20 and 50 years of age. The frequencies of pseudarthrosis and infection are relatively lower after the surgical procedure. Approximately 2 to 7% of patellar fractures are open fractures. Their classification is descriptive. Conclusions: The patella is the largest sesamoid bone in the human body with several important functions. Frequently, patellar fractures appear after falls on the knee, blows and unexpected and energetic muscular pulls. The diagnosis is made by means of clinical history, physical examination and complementary radiography. Anteroposterior and lateral projections of the knee should be performed. For conservative treatment it is essential that the knee extensor mechanism is intact. There are several methods of surgical treatment, in general the open reduction and internal fixation present good results. Complications include post-traumatic osteoarthritis, alteration or loss of mobility of the knee, refracture, fixation failure, osteonecrosis, intolerance to osteosynthesis material, loss of strength of the extensor mechanism, loss of extension, instability of the patella and pseudoarthrosis. KEY WORDS: patella, knee, fracture, treatment, osteosynthesis.

Lateral retraction could achieve better early postoperative knee function than patellar eversion in total knee arthroplasty: a systematic review and meta-analysis.

Comparisons between patellar eversion (PE) and lateral retraction (LR) in total knee arthroplasty (TKA) are still inconclusive. To determine the most suitable procedure, we aimed to evaluate the safety and efficacy of PE and LR in TKA in this meta-analysis. This meta-analysis complied with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Web-based literature databases, including WANFANG, VIP, CNKI, the Cochrane Library, Embase, and PubMed, were utilized to conduct a comprehensive literature search for studies published until June 2022 that compared PE with LR in primary TKA. The quality of the selected randomized controlled trials (RCTs) was evaluated using guidelines of the Cochrane Reviews Handbook 5.0.2. A total of 10 RCTs, including 782 patients and 823 TKAs, were selected in this meta-analysis. Our results showed that using LR improved postoperative knee extensor function and range of motion (ROM). In addition, PE and LR resulted in similar clinical benefits in terms of Knee Society Function score, pain, length of hospital stay, Insall-Salvati ratio, the occurrence of patella baja, and complications related to the operation. Existing evidence suggested that using LR in TKA improved early postoperative knee function. Similar clinical and radiographic outcomes were obtained 1 year after the procedures were performed. Based on these findings, we recommended the use of LR in TKA. However, studies with large sample sizes are needed to validate these findings.

Individualized Mental Fatigue Does Not Impact Neuromuscular Function and Exercise Performance.

Recent studies have questioned previous empirical evidence that mental fatigue negatively impacts physical performance. The purpose of this study is to investigate the critical role of individual differences in mental fatigue susceptibility by analyzing the neurophysiological and physical responses to an individualized mental fatigue task. In a pre-registered (https://osf.io/xc8nr/), randomized, within-participant design experiment, twenty-two recreational athletes completed a time to failure test at 80% of their peak power output under mental fatigue (individual mental effort) or control (low mental effort). Before and after the cognitive tasks, subjective feeling of mental fatigue, neuromuscular function of the knee extensors, and corticospinal excitability were measured. Sequential Bayesian analysis until it reached strong evidence in favor of the alternative hypothesis (BF10 > 6) or the null hypothesis (BF10 < 1/6) were conducted. The individualized mental effort task resulted in a higher subjective feeling of mental fatigue in the mental fatigue condition: 0.50 (95%CI 0.39 - 0.62) AU compared to control: 0.19 (95%CI 0.06 - 0.339) AU. However, exercise performance was similar in both conditions (control; 410 (95%CI 357 - 463) vs. mental fatigue 422 (95%CI 367 - 477) seconds, BF10 = 0.15). Likewise, mental fatigue did not impair knee extensor maximal force generating capacity (BF10 = 0.928) and did not change the extent of fatigability or its origin after the cycling exercise. There is no evidence that mental fatigue adversely affects neuromuscular function or physical exercise, even if mental fatigue is individualized, computerized tasks seem not to affect physical performance.

Sports activity level after ACL reconstruction is predicted by vastus medialis or vastus medialis obliquus thickness, single leg triple hop distance or 6-m timed hop, and quality of life score.

Recovery after anterior cruciate ligament reconstruction (ACLR) may take > 2years, and younger athletes have higher re-injury risk. The purpose of this prospective longitudinal study was to determine how the early to mid-term Tegner Activity Level Scale (TALS) scores of athletically active males ≥ 2years post-ACLR follow-up was predicted by bilateral isokinetic knee extensor and flexor torque, quadriceps femoris thickness, single leg hop test performance, and self-reported knee function (Knee Injury and Osteoarthritis Outcome Score (KOOS); International Knee Documentation Committee(IKDC) Subjective Assessment score). After ACLR with a hamstring tendon autograft and safely returning to sports at least twice weekly, 23 men (18.4 ± 3.5years of age) were evaluated at final follow-up (mean = 4.5, range = 2-7years). Exploratory forward stepwise multiple regression was used to determine the relationship between independent surgical and non-surgical lower limb variables peak concentric isokinetic knee extensor-flexor torque at 60°/sec and 180°/sec, quadriceps femoris muscle thickness, single leg hop test profile results, KOOS subscale scores, IKDCSubjective Assessment scores, and time post-ACLR on TALS scores at final follow-up. Subject TALS scores were predicted by KOOS quality of lifesubscale score, surgical limb vastus medialis obliquus (VMO) thickness, and surgical limb single leg triple hop for distance (SLTHD) performance. Subject TALS scores were also predicted by KOOS quality of lifesubscale score, non-surgical limb vastus medialis (VM) thickness, and non-surgical limb 6m single leg timed hop (6MSLTH) performance. TALS scores were influenced differently by surgical and non-surgical lower extremity factors. At ≥ 2years post-ACLR, ultrasound VM and VMO thickness measurements, single leg hop tests that challenge knee extensor function, and self-reported quality of life measurements predicted sports activity levels. The SLTHD test may be better than the 6MSLTH for predicting long-term surgical limb function.

The comparison between foam rolling either combined with static or dynamic stretching on knee extensors' function and structure.

Static stretching (SS) and dynamic stretching (DS) in combination with foam rolling (FR) have been attracting attention as warm-up routines in sports. However, the combined and intervention order effects of SS or DS and FR on flexibility, muscle strength, and jump performance are still unclear. Therefore, this study aimed to compare the combined effects of FR and SS or DS with the various intervention orders (i.e., SS + FR, DS + FR, FR + SS, DS + FR) on the function and properties of the knee extensors. Using a crossover, random allocation design, 17 male university students (21.0 ± 1.1 y) performed four conditions combining FR and SS or DS. The measurement included knee flexion range of motion (ROM), pain pressure threshold (PPT), tissue hardness, maximum voluntary isometric contraction (MVC-ISO), maximum voluntary concentric contraction (MVC-CON) torque, and single-leg countermovement jump (CMJ) height of the knee extensors. All interventions significantly (p < 0.01) increased knee flexion ROM (SS + FR: d = 1.29, DS + FR: d = 0.45, FR + SS: d = 0.95, FR + DS: d = 0.49), and significantly (p < 0.01) decreased tissue hardness (SS + FR: d = -1.11, DS + FR: d = -0.86, FR + SS: d = -1.29, DS + FR: d = -0.65). There were no significant changes in MVC-ISO, MVC-CON, and CMJ height in all conditions, but a near significant, small magnitude (p = 0.056, d = -0.31) decrease of MVC-ISO was observed in the FR + SS condition. Our results showed that all the combinations of SS or DS and FR effectively decreased tissue hardness and increased ROM without decreasing muscle strength. Also, effect sizes indicated the largest increase in ROM and decrease in tissue stiffness after SS + FR without decreasing muscle strength and jump performance.

Influence Of Knee Extensor Strength On Spatiotemporal Gait Parameters In Adults With Prader-willi Syndrome

Adults with Prader-Willi Syndrome (PWS) are at greater risk for falls, which may be due to impaired muscle and gait performance. PURPOSE: To compare spatiotemporal gait parameters between adults with and without PWS, and to explore associations between knee extensor strength and spatiotemporal gait parameters in adults with PWS. METHODS: 10 adults with PWS, and 10 controls with and 10 without obesity completed isometric knee extensor (KE) strength assessments and gait analyses. Strength outcomes included peak KE torque, and early and late KE rate of torque development (RTD). Gait outcomes included speed, step length, step width, double support time, cadence, and gait-stability ratio (GSR). Step length and width were normalized to height, and strength outcomes were normalized to lean mass. Gait and strength outcomes were compared between groups with one-way MANOVA, and post hoc tests were made using Tukey’s HSD. Associations between strength and gait outcomes were explored using 1-tailed Pearson and Spearman correlations in the group with PWS. RESULTS: Gait (Pillai’s Trace = 0.86, p = 0.01) and strength outcomes (Pillai’s Trace = 0.52, p = 0.01) differed between groups. Adults with PWS had shorter step length (p < 0.01), longer double support (p = 0.01), and slower gait speed (p = 0.02) compared with controls without obesity, and higher GSR compared with controls without obesity (p = 0.01) and with obesity (p = 0.04). Adults with PWS had less KE torque (p < 0.01), early (p < 0.01) and late (p < 0.001) RTD compared with controls without obesity; and less KE torque (p = 0.01), less early (p = 0.03) and late (p = 0.01) RTD. In adults with PWS, greater KE torque was associated with faster speed (rho = 0.57, p < 0.01), smaller step width (r = -0.62, p = 0.03), shorter double support time (r = -0.57, p = 0.04), and lower GSR (rho = -0.79, p < 0.01). Greater late RTD was associated a faster speed (rho = 0.79, p = 0.01), lower GSR (rho = -0.71, p = 0.01), and longer step length (rho = 0.71, p = 0.01). CONCLUSIONS: Adults with PWS have different spatiotemporal gait parameters compared with controls that contribute to slower gait speed and reduced mobility. Larger GSR may reflect an adaptive strategy to increase ground contact time and avoid dynamic portions of the gait cycle. Improving knee extensor function may be useful to increase gait performance in adults with PWS.

Assessment of Viscoelastic Parameters of Muscles in Children Aged 4-9 Months with Minor Qualitative Impairment of the Motor Pattern after Vojta Therapy Implementation.

The aim of this study was to assess if there are any objective changes in the viscoelastic parameters of the erector spinae muscle after Vojta stimulation. The study involved 22 healthy children at an average age of 7 months and with an Apgar score of 8–10 points, who were referred for rehabilitation due to a slight delay in the phases of psychomotor development. The first group consisted of 11 children with increased muscle tone (IMT) and the second group consisted of 11 children with non-increased muscle tone (nonIMT). All study participants received a one-time Vojta therapy session, which was continued for 4 weeks by parents at home. The viscoelastic parameters of the dorsal extensor muscle were measured three times. In the first study group, changes in the viscoelastic parameters of the extensor muscles of the back occurred immediately after the therapy at the first examination, whereas changes in the supporting and extensor function of the limbs occurred in both groups at the second examination. Analysis featuring an objective assessment allows physiotherapists to diagnose local changes in the viscoelastic parameters after the implementation of therapy. These studies are the first pilot studies to be continued with a 30- or 60-day follow-up.

Peripheral muscle function during repeated changes of direction in professional soccer players.

To evaluate peripheral muscle function of the knee extensors during repeated changes of direction in professional soccer players by examining differences between competitive levels, periods of the season and playing positions, and to investigate the relationships between peripheral muscle function and physical activities during matches. Knee extensor peripheral muscle function (twitch peak torque, PT) of 593 male soccer players from 13 European professional clubs competing at 3 different levels was evaluated 4 times during the season. The main outcomes were PTmax (maximal PT, muscle contractility), MPmax (maximal metabolic power exercise intensity) and PTdec (PT decline, muscle fatigability) obtained during intermittent runs of increasing intensity with multiple changes of direction interspersed with electrically evoked contractions. Relative total and sprint distances covered during a whole match and during short intervals were quantified from a sub-sample. PTmax and MPmax were higher for first than for second division (p < 0.047; d = 0.15-0.23) and Under-19 players (p < 0.007; d = 0.17-0.25). MPmax was lower (p < 0.016; d = 0.23-0.32) and PTdec was higher (p < 0.004; d = 0.26-0.39) in the pre-season compared to all the other time points. MPmax was higher for fullbacks than attackers and defenders (p < 0.041; d = 0.20-0.22). PTdec was higher for defenders than fullbacks, midfielders and wings (p < 0.029; d = 0.21-0.28). PTmax was associated with whole-match relative total distance (p = 0.004; d = 0.26). PTdec was associated with whole-match relative total distance and relative short-interval sprint distance (p < 0.050; d = 0.18-0.22). The ability to sustain repeated change of direction efforts at high intensities while preserving peripheral muscle function should be considered an important determinant of soccer physical performance.

Very old adults show impaired fatigue resistance compared to old adults independently of sex during a knee-extensors isometric test.

The present study aimed to investigate age-related differences in fatigability induced by an isometric quadriceps intermittent fatiguing test in 30 young (<35years old, 15 females), 19 old (>60years old, 9 females) and 30 very old (>80years old, 15 females) adults. Maximal force loss, contractile function and voluntary activation of the knee extensors were evaluated throughout an isometric fatiguing test using femoral nerve magnetic stimulations. Older adults performed more contractions (index of relative performance) than young (P=0.046) and very old adults (P=0.007), without differences between young and very old adults (P=1.000). Force-time integral (absolute performance) was greater for young and old adults compared to very old adults (P<0.001), without differences between young and old adults (P=0.124). At exhaustion, force loss was greater for young (-28±9%) compared to old adults (-19±8%; P=0.002), but not very old adults (-23±8%; P=0.106), and no difference between old and very old adults (P=0.414). Data from the interpolated twitch technique suggested similar alteration in contractile function with age, with no impairments in voluntary activation. Impairments were similar across sexes. This study showed that older adults were less fatigable than young adults during an isometric intermittent fatiguing task of the knee extensors. This greater fatigue resistance was not maintained in very old adults independent of sex. Fatigability at exhaustion was likely due to impairments in contractile function for the three age groups.

Sagittal Spinal Mobility and Back Extensor Muscle Function in Older Females with Age-Related Hyperkyphosis

Introduction: Spinal range of motion (ROM) is a potential and modifiable variable that may contribute to the maintenance of upright sagittal alignment. The present study aimed to compare spinal ROM in older females with and without hyperkyphosis and investigate associations between thoracic kyphosis and spinal ROM, back extensor strength (BES), and back extensor endurance (BEE).Materials and Methods: Sagittal spinal curvature and ROM were measured with the Spinal Mouse. Also, BES and BEE were assessed with a load cell. Variables were compared between older females with and without hyperkyphosis with the independent sample t test. We used the Pearson correlation coefficient to calculate associations between variables. Multiple linear regression was used to find which variable is best associated with kyphosis.Results: Lumbar and total spinal ROM were lower in the hyperkyphosis compared to the normal group (P&lt;0.05). Thoracic kyphosis was associated with total lumbar ROM (r=-0.30, P=0.03), total spinal ROM (r=-0.35, P=0.01), BES (r=-0.73, P&lt; 0.001), and BEE (r=-0.60, P&lt; 0.001). Multiple linear regression analysis after adjusting for age, weight, and BMI showed that BES (P&lt;0.001) and BEE (P=0.01) but not spinal ROM (P=0.16) were significantly associated with thoracic kyphosis.Conclusion: Females with hyperkyphosis had lower spinal ROM than those with normal kyphosis. While thoracic kyphosis was significantly associated with total lumbar ROM, total spinal ROM, BES, and BEE, multivariate regression showed that ROM was not a significant contributor to thoracic kyphosis. BES and BEE were significant contributors to thoracic kyphosis and should be targeted in the rehabilitation of hyperkyphosis.

Evaluation of tautening method in repair of advanced mallet finger without bone fracture

Many different repair methods have been described in the frequently seen mallet finger deformity, but without consensus. The present study aimed to present an alternative tautening technique in mallet finger repair and to compare it versus classical direct repair. Patients with untreated chronic mallet finger of more than three months’ progression, treated surgically between March 2017 and October 2020, were included. Two surgical methods were applied to restore extensor function of the distal interphalangeal joints. In the first group, the granulation tissue was excised and the extensor tendon was repaired directly. In the second group, granulation tissue was not excised, and the extensor tendon was tautened by plication. Outcomes were evaluated according to Miller’s criteria. Fort-six patients were included: group 1, 25 patients; group 2, 21 patients. Mean age in group 1 was 36.2 years and 33.4 years in group 2. Mean follow-up in group 1 was 14.8 months and 13.9 in group 2. Extensor lag was similar (5.6°) in both groups at the end of the sixth month. On Miller’s mallet finger criteria, group 1 scored 3.4 points and group 2 3.4 points (p > 0.05). The tendon tautening method helps to start physiotherapy early, the learning curve is short, and it provides functionally positive results and a low complications rate. We think that this method should be evaluated in chronic mallet finger deformities without bone fracture.

Age-related reduction in peak power and increased postural displacement variability are related to enhanced vestibular-evoked balance responses in females.

Adult aging is associated with reductions in muscle function and standing balance control. However, whether sensorimotor function adapts to maintain upright posture in the presence of age-related muscle weakness is unclear. The purpose was to determine whether vestibular control of balance is altered in older compared to younger females and whether vestibular-evoked balance responses are related to muscle power. Eight young (22.6±1.8years) and eight older (69.7±6.7years) females stood quietly on a force plate, while subjected to random, continuous electrical vestibular stimulation (EVS; 0-20Hz, root mean square amplitude: 1.13mA). Medial gastrocnemius (MG) and tibialis anterior (TA) surface electromyography (EMG) and force plate anterior-posterior (AP) forces were sampled and associated with the EVS signal in the frequency and time domains. Knee extensor function was evaluated using a Biodex multi-joint dynamometer. The weaker, less powerful older females exhibited a 99 and 42% greater medium-latency peak amplitude for the TA and AP force (p<0.05), respectively, but no other differences were detected for short- and medium-latency peak amplitudes. The TA (<10Hz) and MG (<4Hz) EVS-EMG coherence and EVS-AP force coherence (<2Hz) was greater in older females than young. A strong correlation was detected for AP force medium-latency peak amplitude with center of pressure displacement variability (r=0.75; p<0.05) and TA medium-latency peak amplitude (r=0.86; p<0.05). Power was negatively correlated with AP force medium-latency peak amplitude (r=-0.47; p<0.05). Taken together, an increased vestibular control of balance may compensate for an age-related reduction in power and accompanies greater postural instability in older females than young.

Physiological Responses to Acute Cycling With Blood Flow Restriction.

Aerobic exercise with blood flow restriction (BFR) can improve muscular function and aerobic capacity. However, the extent to which cuff pressure influences acute physiological responses to aerobic exercise with BFR is not well documented. We compared blood flow, tissue oxygenation, and neuromuscular responses to acute cycling with and without BFR. Ten participants completed four intermittent cycling (6 × 2 min) conditions: low-load cycling (LL), low-load cycling with BFR at 60% of limb occlusion pressure (BFR60), low-load cycling with BFR at 80% of limb occlusion pressure (BFR80), and high-load cycling (HL). Tissue oxygenation, cardiorespiratory, metabolic, and perceptual responses were assessed during cycling and blood flow was measured during recovery periods. Pre- to post-exercise changes in knee extensor function were also assessed. BFR60 and BFR80 reduced blood flow (~33 and ~ 50%, respectively) and tissue saturation index (~5 and ~15%, respectively) when compared to LL (all p < 0.05). BFR60 resulted in lower VO2, heart rate, ventilation, and perceived exertion compared to HL (all p < 0.05), whereas BFR80 resulted in similar heart rates and exertion to HL (both p > 0.05). BFR60 and BFR80 elicited greater pain compared to LL and HL (all p < 0.05). After exercise, knee extensor torque decreased by ~18 and 40% for BFR60 and BFR80, respectively (both p < 0.05), and was compromised mostly through peripheral mechanisms. Cycling with BFR increased metabolic stress, decreased blood flow, and impaired neuromuscular function. However, only BFR60 did so without causing very severe pain (>8 on pain intensity scale). Cycling with BFR at moderate pressure may serve as a potential alternative to traditional high-intensity aerobic exercise.