Isokinetic Protocol Research Articles

Analysis of intrarater and interrater reliability of the interactive line protocol for evaluating neuromuscular function in patients with knee injury and observation of psychological state changes.

The isokinetic interactive line protocol (ILP) appears to enhance neuromuscular function and may reduce posttraumatic stress and anxiety. However, the reliability of the protocol has not been investigated, nor has it been analyzed in relation to psychological states. A total of 165 participants took part in this study, with ages ranging from 21 to 24 years. The gender distribution was 68.4% male and 31.6% female. There was no significant difference in injury duration between males and females (z=-0.922, P=0.357). The intrarater reliability of the ILP, as indicated by the intraclass correlation coefficient, was high for both concentric and eccentric contractions of the quadriceps (ranging from 0.891 to 0.980). Likewise, the interrater reliability for these contractions was also high (range, 0.873-0.943). Additionally, during the ILP, there was a significant reduction in posttraumatic stress (t=9.795, P<0.001) and anxiety (t=5.965, P<0.001) related to knee reinjury after 2 weeks. Ultimately, the isokinetic game ILP demonstrates high intra- and interrater reliabilities and can be concluded to effectively reduce posttraumatic stress and anxiety when incorporated into retesting.

Isokinetic Knee Strengthening Impact on Physical and Functional Performance, Pain Tolerance, and Quality of Life in Overweight/Obese Women with Patellofemoral Pain Syndrome.

Background/Objectives: Patellofemoral syndrome is a common osteoarticular condition that affects many individuals. Various treatment options are available, with a significant emphasis on targeted muscle-strengthening exercises. The purpose of this study was to investigate the effect of isokinetic muscle strengthening on muscle strength, joint range of motion, quality of life, physical performance, and pain tolerance in overweight/obese women with patellofemoral syndrome. Methods: Twenty-four overweight or obese women with patellofemoral syndrome participated in the study during September and October 2023 in a private medical facility for physical medicine and functional rehabilitation. They were randomly assigned to one of two groups for six weeks of isokinetic muscle strengthening. The first group (ISO.G) followed a rehabilitation program combined with isokinetic muscle strengthening. A second group (PCM.G) followed a rehabilitation program that includes an isokinetic protocol in passive compensation movement. The extensors' peak torque was measured before and after training. Results: The flexors' peak torque, stair climbing test, 10 m walk, chair lift, monopodal support, goniometric knee flexion test, heel-buttock distance measurement, pain, and quality of life scores improved significantly in both groups. The ISO.G, on the other hand, benefited from a significant increase in quadriceps muscle strength revealed by the extensors' peak torque. Conclusions: For the treatment of patellofemoral syndrome, isokinetic muscle strengthening in concentric mode appears to have a significant advantage over the classic rehabilitation program with isokinetic passive compensation, particularly in muscle strength gain, in addition to the improvement of joint range of motion, quality of life, physical performance, and pain tolerance. Isokinetic training may be recommended as a beneficial approach for the rehabilitative treatment of patellofemoral pain syndrome in overweight/obese women.

Biomechanical Examination of Wrist Flexors and Extensors with Biodex System Dynamometer-Isometric, Isokinetic and Isotonic Protocol Options.

Background and Objectives: Biodex System® is an advanced dynamometer used for testing various biomechanical parameters of muscles. Test outcomes allow for the identification of muscle pathology and consequently lead to a clinical diagnosis. Despite being widely used for the testing and rehabilitation of the human musculoskeletal system, no universal and acceptable protocol for wrist examination has been proposed for patients with wrist pathology. In this study, the authors aim to identify the most appropriate protocol for testing the biomechanical parameters of flexors and extensors of the wrist. Materials and Methods: A group of 20 patients with symptomatic tennis elbow and 26 healthy volunteers were examined using three different protocols: isokinetic, isometric and isotonic. Protocol order for each study participant was assigned at random with a minimum of a 24 h break between protocols. All protocol parameters were set according to data obtained from a literature review and an earlier pilot study. Following completion of each protocol, participants filled out a questionnaire-based protocol, assessing pain intensity during the exam, difficulty with exam performance and post-exam muscle fatigue. Results: The isotonic protocol showed the best patient tolerance and the highest questionnaire score. There was a significant difference (p < 0.05) between the three protocols in average pain intensity reported by study participants. All participants completed the isotonic protocol, but not all patients with symptomatic tennis elbow were able to complete the isometric and isokinetic protocols. The isotonic protocol was deemed "difficult but possible to complete" by study participants. Conclusions: The isotonic protocol is most suitable for testing the flexors and extensors of the wrist. It gives the most biomechanical data of all protocols, is well tolerated by patients and rarely causes pain during examination even in symptomatic participants.

Comparison of isokinetic exercise and standard exercise protocol in patients with spondyloarthropathies

Introduction: Spondyloarthropathy is a group of different chronic rheumatic diseases. There are a number of physiotherapy interventions that all aim to support the trunk flexors and extensors, relieve pain, and mobilize the joints. The aim of this study is to compare isokinetic exercises (IE) with a standard exercise protocol in patients with spondyloarthropathies. Methods: A total of 16 subjects participated in the study and were randomly divided into two groups: The group with the standard protocol (SP) and the other in the isokinetic protocol (IP). Both groups underwent the same follow-up testing: Muscle strength, pain, and functional status. Both groups underwent a total of 15 physiotherapy interventions over a 3-week period. Results: The mean age in the standard group was 36 ± 7.93 and in the isokinetic group 46.13 ± 13.88. In the isokinetic group, there was a difference in pain intensity between the second and third measurements (p = 0.016). There was an improvement in muscle strength in the isokinetic group (Cohen’s d = 0.33). At an angular velocity (AV) of 60°/s, this group is better than the delayed SP, while it is directly better at an AV of 90°/s (d = 0.30). The delayed measurement of the groups (IP) showed a lower functional deficit than the SP group (p = 0.012). Conclusion: Based on the results of this study and a search of the scientific literature, we can conclude that IE has been shown to be beneficial rather than harmful. Further longitudinal studies with a larger number of subjects are needed to investigate the effects of isokinetics on functional outcomes in rheumatology patients.

Evaluation de la force musculaire chez le lombalgique chronique: Comparaison entre reeducation isocinetique et reeducation classique

Chronic low back pain is a public health problem in view of its functional repercussions and the functional rehabilitation is an integral part of its management. To compare the evolution of muscle strentgh of spinal extensors and flexors in chronic low back pain patients after an isokinetic rehabilitation protocol and a conventional rehabilitation one. This was a prospective and comparative study carried out in the Physical Medicine Department of the Tunis Military Hospital over a period of 7 months. Fifty patients were included, randomly divided into two groups of 25. The first group (G1) benefited from an isokinetic rehabilitation protocol and the second one (G2) from a classic active physiotherapy. We performed a clinical (Sorensen test and Shirado test) and isokinetic evaluation of the trunk muscles before and after rehabilitation. The mean age of the general population was 42±8.6 years old. Clinical evaluation showed a deficit in the extensor and flexor muscles of the spine, more important in the extensors in both groups. After rehabilitation, there was a significant improvement in clinical tests of muscular endurance in G1 and G2. Isokinetic assessment showed a greater muscle deficit in the extensors in both groups. After isokinetic rehabilitation, peak torque for flexors and extensors increased by 21% and 23% respectively, power was 34% and 37% higher, and total work increased by 26% and 47%. On the other hand, the (F/E) ratios were unchanged for all three speeds. In Group 2, peak torque values for flexors and extensors increased by 22 and 15% respectively, power was higher by 31 and 23% and total work was also up by 29 and 17%, while F/E ratios were also unchanged. Group 1 showed the greatest improvement in extensor strength at 60°/s, and in power at 90°/s for the various muscles. In our study, we concluded that endurance and muscular strength improved the most after isokinetic rehabilitation.

Association between Serum Biomarkers of Muscle Damage after Isokinetic Eccentric Exercise in Trained Males and Females

Eccentric exercise is well-known to induce muscle damage, and biomarkers may be related to the magnitude of impact on muscle force and muscle soreness after exercise. However, this phenomenon still needs to be investigated in more detail. The present study aimed to analyze if a correlation between muscle force, soreness, and biomarkers after eccentric exercise exists in healthy, trained 11 males and females. Eleven volunteers with previous resistance training experience performed 6 x 10 maximal isokinetic eccentric contractions of the elbow flexors in the muscle performance laboratory up to 72 hours after exercise. Peak torque was measured by maximal voluntary isometric contractions (MVIC) and muscle soreness by visual analogic scale (VAS) before, 24h, 48h, and 72h after the isokinetic eccentric exercise protocol. A fluorescence immunoassay analyzer determined Myoglobin and C-reactive protein levels. The MVIC significantly decreased while muscle soreness increased 24h, 48h, and 72h post eccentric exercise. Myoglobin significantly increased 48h and 72h after exercise. Muscle soreness was inversely correlated with MVIC 24h, 48h, and 72h and positively correlated with myoglobin 48h and 72h after eccentric exercise. The myoglobin was not correlated with muscle force. No significant correlation between C-reactive protein and muscle soreness and MVIC was found. In conclusion, our data suggest that myoglobin could be a valuable biomarker to be assessed alongside exercise-induced muscle soreness.

Shoulder rotator strength in judo athletes: A cross-sectional study with different experience levels

BACKGROUND: Judo practice requires high effort from athletes, mainly focused on the upper limbs, involving the shoulder complex. OBJECTIVE: To compare the shoulder internal (IR) and external (ER) rotation peak torque and conventional ratio (ER: IR) between judo athletes from different experience levels (novice vs. advanced) and to verify the distribution of athletes according to the ER: IR ratio classification. METHODS: Thirty-nine male judo athletes were divided into two groups (advanced: 20.5 ± 2.8 years and novice: 22.1 ± 5.5 years). The athletes performed a shoulder isokinetic protocol to measure IR and ER strength and the ER: IR ratio in novice and advanced groups. Chi-square tests were used to investigate the distribution of athletes according to the different groups of ER: IR ratio classification, and t-tests were used to compare the IR and ER peak torque and the ER: IR ratio between novice and advanced groups, with the level of significance set at 5%. RESULTS: The main results showed higher values of IR peak torque (77.3 ± 15.7 N⋅m in advanced vs. 48.2 ± 8.4 N⋅m in novices; p= 0.013), and a lower ER: IR conventional ratio in advanced athletes compared to novices (0.63 ± 0.1 advanced vs. 0.73± 0.2 in novice; p= 0.01). When individual values were analyzed, advanced athletes presented higher imbalance (&lt; 0.66 ER: IR ratio) than novices (p= 0.023). CONCLUSION: Advanced athletes presented higher shoulder IR peak torque, but higher imbalance in the ER: IR ratio than novices, probably because the long-term training induced an increase in IR strength without concomitant development in ER strength. Coaches and strength and conditioning trainers should monitor shoulder rotator strength in judo athletes to avoid muscle imbalances in this region, which is frequently employed in judo training routines.

Relationship between Volitional and Non-Volitional Quadriceps Muscle Endurance in Patients with Chronic Obstructive Pulmonary Disease.

Volitional assessment of quadriceps muscle endurance is clinically relevant in patients with chronic obstructive pulmonary disease (COPD). However, studies that determine the construct validity of volitional tests by comparing them to non-volitional measures are lacking. Therefore, the aim of the current study is to evaluate the correlation between volitional and non-volitional quadriceps muscle endurance in patients with COPD. Quadriceps muscle endurance was evaluated in twenty-six patients with COPD. A volitional isometric and a volitional isokinetic protocol were performed on a computerised dynamometer to determine the isometric time and isokinetic work fatigue index, respectively. Non-volitional assessment of quadriceps muscle endurance was evaluated using repetitive electrical stimulations to establish the isometric muscle force decline. Sixteen patients (61 ± 8 years, 63% male, FEV1 47 (32-53)%) performed all three quadriceps endurance tests conforming to pre-defined test criteria. Both volitional isometric time and isokinetic work fatigue index did not significantly correlate with non-volitional muscle force decline (both p > 0.05). There was a strong correlation between volitional isometric time and isokinetic work fatigue index (rho = -0.716, p = 0.002). To conclude, this study suggests that volitional measures evaluate partly different aspects of quadriceps muscle endurance compared to non-volitional measures. Accordingly, these outcome measures cannot be used interchangeably.

Exploring the issue of ‘functionality’ in isokinetic dynamometry

ABSTRACT Strength is a primary and modifiable contributor to performance, injury risk, and rehabilitative success. The gold standard measure of strength is the isokinetic dynamometer, providing the clinician with the opportunity to manipulate contraction modality, range, and speed about a joint. However, criticism has highlighted a lack of functional relevance, with arbitrary selection of speed across the full range. To better understand function, biomechanical analysis of movement can inform a bespoke isokinetic data collection protocol. In this case, we use walking gait, a function goal for daily living and clinically assessed following knee replacement surgery for example. Concentric knee flexor and extensor demand was evident at an average angular velocity of 70°·s−1, whilst eccentric knee flexor and extensor demands were evident at speeds of 192°·s−1 and 165°·s−1, respectively. The efficacy of isokinetic dynamometry can be enhanced with bespoke data collection protocols, which better reflect the functional demands of the clinical movement objective.

Differences in Strength and Fatigue Resistance of Scapular Protractors and Retractors Between Symptomatic and Asymptomatic Dyskinesis.

Scapular dyskinesis is a shoulder dysfunction that can be asymptomatic or associated with pain or weakness. Reduced strength and fatigue resistance of the scapular protractor and retractor muscles that stabilize the scapula might contribute to dyskinesis. To determine the strength and fatigue resistance profiles of participants with symptomatic or asymptomatic scapular dyskinesis and compare them with healthy control (HC) individuals using isokinetic assessment. Cross-sectional study. University hospital. Twenty HC individuals and 21 overhead athletes with symptomatic (n = 10) or asymptomatic (n = 11) scapular dyskinesis. Strength (peak torque, maximum work), fatigue resistance (total work), and protraction:retraction ratios measured during a closed chain isokinetic protocol (40 repetitions in concentric mode at 24.4 cm/s). The scapular protractors' strength and fatigue resistance were higher (P < .01) in HC individuals (peak torque = 5.0 ± 0.9 N/kg, maximum work = 2.4 ± 0.5 J/kg, total work = 72.4 ± 0.6 J/kg) than in asymptomatic (peak torque = 3.4 ± 0.7 N/kg, maximum work = 1.7 ± 0.4 J/kg, total work = 50.0 ± 13.7 J/kg) or symptomatic (peak torque = 3.8 ± 0.6 N/kg, maximum work = 1.8 ± 0.3 J/kg, total work = 58.1 ± 12.9 J/kg) dyskinetic participants. The symptomatic dyskinetic group presented the highest retractor strength and fatigue resistance (P < .01) values (peak torque = 5.2 ± 0.6 N/kg, maximum work = 2.9 ± 0.8 J/kg, total work = 87.7 ± 22.7 J/kg), followed by the HC individuals (peak torque = 4.7 ± 1.0 N/kg, maximum work = 2.1 ± 0.5 J/kg, total work = 65.3 ± 17.9 J/kg) and the asymptomatic dyskinetic participants (peak torque = 3.9 ± 1.0 N/kg, maximum work = 1.9 ± 0.6 J/kg, total work = 58.6 ± 18.5 J/kg). The protraction:retraction ratios showed a gradual decrease (P < .001) from the HC individuals (1.1) to the asymptomatic (0.9) and symptomatic (0.7) dyskinetic participants. Scapular dyskinesis is characterized by weaker scapular protractors and reduced agonist:antagonist ratios, especially when patients are symptomatic. Targeting the scapular protractors to achieve a better balance of scapular musculature in rehabilitation and strengthening programs may improve shoulder symptoms and function, but more interventional studies are required.

Learning effect on an isokinetic knee strength test protocol among male adolescent athletes.

Learning effect occurs when the best performance is not achieved at the earliest trial of a repeated protocol of evaluation. The present study examined, within testing session, the intra-individual variation in an isokinetic strength protocol composed of five reciprocal concentric and eccentric contractions of knee extensors (KE) and knee flexors (KF) among male adolescent swimmers. Additionally, test-retest reliability was determined as intra-individual mean differences between two consecutive testing sessions. The sample included 38 swimmers aged 10.1-13.3 years. A subsample (n = 17) completed a second visit. Isokinetic dynamometry was used to assess concentric and eccentric contractions of KE and KF at an angular velocity of 60°.s-1. The protocol included three preliminary repetitions that were not retained for analysis, a 60-second interval, and five reciprocal maximal concentric contractions (cc). The preceding sequence was repeated for eccentric contractions (ecc) of KE and KF. Multilevel regression confirmed intra-individual and inter-individual levels as significant sources of variance in peak torque (PT) values. Intra-class correlation (ICC) fluctuated between 0.582 and 0.834 and, in general, a substantial percentage of participants need more than three repetitions to attain their best PT: KEcc (36.8%), KEecc (23.7%), KFcc (39.5%), KFecc (18.4%). For the subsample of 17 swimmers who completed a second testing session, intra-individual mean differences of the best PT were trivial or small. In summary, the validity of shorter protocols may be compromised if swimmers do not attain their best peak torque in the first few attempts, and the reliability of a 5-repetition protocol seemed acceptable.

Development of a Control Strategy in an Isokinetic Device for Physical Rehabilitation.

Robotic-assisted rehabilitation is currently being applied to improve the effectiveness of human gait rehabilitation and recover the mobility and strength after a stroke or spinal cord injury; a robotic assistant can allow the active participation of the patient and the supervision of the collected data and decrease the labor required from therapists during the patient's training exercises. The goal of gait rehabilitation with robotic-based assistance is to restore motor function by using diverse control strategies, taking account of the physical interaction with the lower limbs of the patient. Over the last few years, researchers have extracted useful information from the patient's biological signals that can effectively reflect movement intention and muscle activation. One way to evaluate progress in rehabilitation is through isokinetic prototype tests that describe the dynamic characteristics of an isokinetic leg extension device for rehabilitation and control action. These tests use an isokinetic system to assess muscle strength and performance in a patient during isometric or isokinetic contraction. An experimental prototype shown in the following work allows the device's performance to be evaluated in a controlled environment before the patient's use. New features provide a control system that can be teleoperated for distributed structures, enabling the remote operation and management of the device. In order to achieve physical recovery from musculoskeletal injuries in the lower limbs and the reintegration of the affected subject into society as an independent and autonomous individual in their daily activities, a control model that introduces a medical isokinetic rehabilitation protocol is presented, in which the element that carries out such protocol consists of a magnetic particle brake whose control action is strongly influenced by the dynamics of the system when in contact with the end user-specifically, the patient's legs in the stretch from the knee to the ankle. The results of these tests are valuable for health professionals seeking to measure their patient's progress during the rehabilitation process and determine when it is safe and appropriate to advance in their treatment.

Changes in knee flexion-extension performance and hamstring-to-quadriceps ratio during a fatiguing isokinetic protocol in male professional futsal players

ABSTRACT Knee flexion (KF) and extension (KE) performance and hamstring-to-quadriceps (H:Q) ratio are used to estimate injury risk and readiness to return to sport. However, the traditional measures (i.e. non-fatigued state and by peak torque [PT]) may not reflect the thigh and knee injury conditions (i.e. high-speed actions and fatigue presence). We verified the effects of a high-speed isokinetic fatigue protocol (30 consecutive KF and KE concentric contractions at 300°/s) on KF and KE performance and H:Q ratios assessed through different parameters (i.e. PT, work, average and peak power) in male professional futsal players (n = 17). A significant (p < 0.01) time × muscle group interaction was verified. There were reductions (p < 0.01) in KF by PT (84.79 ± 15.05 to 50.29 ± 15.29 Nm), work (87.28 ± 14.46 to 39.00 ± 13.83 Nm), average power (227.81 ± 39.31 to 104.75 ± 31.24 W) and peak power (383.40 ± 59.90 to 191.39 ± 48.35 W). Similarly, KE performance decreased (p < 0.01) for all parameters (PT: 131.36 ± 16.05 to 81.61 ± 9.15 Nm; work: 148.83 ± 20.88 to 90.72 ± 11.89 Nm; average power: 148.83 ± 20.88 to 90.72 ± 11.89 W; peak power: 664.74 ± 85.32 to 398.38 ± 42.42 W). KF (−55.18 ± 13.91% to −40.94 ± 12.66%) showed a higher percentage decrease than KE (−40.46 ± 7.38% to −37.45 ± 6.61%). Finally, reductions (p < 0.01) in H:Q ratio by work, average and peak power but not by PT (p = 0.25) were verified. The tested methods can provide additional information about the athlete’s condition.

Eccentric, but not concentric muscle contraction induce inflammation and impairs fibrinolysis in healthy young men.

Different types of muscle contraction can cause different damage to the musculature and differences in inflammatory responses. Acute increases in circulatory inflammation markers can influence the crosstalk between coagulation and fibrinolysis processes, increasing the risk of thrombus formation and detrimental cardiovascular events. The aim of this study was to analyze the effects of concentric and eccentric exercise on hemostasis markers, C-reactive protein (CRP), and the relationship between these variables. Eleven healthy subjects with a mean age of 25.4±2.8, non-smokers, with no history of cardiovascular disease and blood type O, randomly performed an isokinetic exercise protocol consisting of 75 concentric (CP) or eccentric (EP) contractions of knee extension, divided into five sets of 15 repetitions combined with 30-s rest. Blood samples for analysis of FVIII, von Willebrand factor, tissue plasminogen activator (t-PA), plasminogen activator inhibitor type-1 (PAI-1), and CRP were collected pre, post, 24 h, and 48 h after each protocol. Increased levels of CRP at 48 h in EP versus CP (p=0.002), increased PAI-1 activity 48 h in EP versus CP (p=0.044), and a reduction in t-PA at 48 h when compared with post-protocol in both protocols (p=0.001). A correlation was found between CRP and PAI-1 at 48 h of PE (r2=0.69; p=0.02). This study showed that both EP and CP increase the clotting process, albeit only the exercise performed eccentrically induces inhibition of fibrinolysis. This is possibly due to the increase in PAI-1 48 h after the protocol, which correlates with the increase in inflammation as demonstrated by the CRP levels.

The Effectiveness of an Isokinetic Training Protocol on Muscular Imbalances in Professional Soccer Players Following an ACL Reconstruction

It has been indicated that strength imbalances following an ACL reconstruction are essential indicators of incomplete rehabilitation programs and increased risk for re-injury. This study evaluated the effectiveness of an isokinetic training protocol on muscular imbalances in soccer players who underwent ACL surgery. Twenty-four elite male soccer players who were found to have strength imbalances six months post-surgery were recruited and randomly assigned to either the control or the experimental group. The isokinetic knee strength was assessed before and after the 5-week intervention program. Two-way analysis of variance (ANOVA) revealed a significant main effect of training intervention on torque production for the quadriceps [F(1,22)= 34.95, p<0.001, <img src=image/19927570_01.gif>=0.61] and the hamstring [F(1,22)= 11.49, p<0.05, <img src=image/19927570_01.gif>=0.34] of the operated leg. Furthermore, there was a significant interaction between the exercise condition and torque production for the quadriceps [F(1,22)= 23.46, p<0.001, <img src=image/19927570_01.gif>=0.52] and the hamstring of the operated leg [F(1,22)=6.27, p<0.05, <img src=image/19927570_01.gif>=0.22]. Planned comparisons revealed that the experimental group produced significantly greater quadriceps [t(11)= -5.42, p<0.01, d=1.22] and hamstring [t(11)=-3.09, p<0.01, d=0.45] torque post-training compared to the pre-training intervention. Additionally, there was a main effect of training intervention on the deficits of the quadriceps [F(1,22)=67.95, p<0.01, <img src=image/19927570_01.gif>=0.76] and a significant interaction between the exercise intervention and quadriceps deficits for the two groups [F(1,22)= 32.48, p<0.001, <img src=image/19927570_01.gif>=0.59]. Our results indicate that the isokinetic training program efficiently restored the muscular imbalances post-surgery, and therefore physical therapists and rehabilitation experts should consider incorporating this program into their therapy protocols.

The effect of knee angle and subject position on plantar flexors isokinetic performance and muscular activity

BACKGROUND: Assessment of the plantar flexion (PF) isokinetic performance has been greatly diverse and based on personal preferences rather than standardized guidelines. OBJECTIVE: To examine the performance of the plantar flexors under different settings including knee joint angle and subject position. METHODS: Thirteen women and 20 men took part in this study. The isokinetic protocol (60∘/s) was set to ankle movement between 10∘ dorsiflexion to 30∘ PF. Participants performed three repetitions of concentric PF in randomly-ordered knee angles; 15∘, 45∘ and 90∘, and in seated and supine positions. Surface electromyography (EMG) data were collected from the Soleus (SOL) and Gastrocnemius. RESULTS: Knee angle impacted the PF moment (P⩽ 0.001–0.026) and work (P⩽ 0.05) measures in both genders. The moment and work measures were significantly less in the 90∘ than those in the 45∘ and 15∘ positions. The 45∘ position had the highest values, particularly in sitting in the male participants. Only the GL EMG data was significantly impacted (P= 0.017) by the subject position. However, the difference was trivial (1.6%). The SOL muscle showed a consistent pattern of increased activity when the knee was in flexion. CONCLUSION: The 45∘ position seems to be optimal for obtaining the highest isokinetic PF scores.

Age differences in upper extremity joint moments and strength during a laboratory-based tether-release forward fall arrest in older women

Age-related declines in upper extremity muscle strength may affect an older adult’s ability to land and control a simulated forward fall impact. The role of individual upper extremity joints during a forward fall impact has not been examined. The purpose was to evaluate the age differences in upper extremity joint moment contributions during a simulated forward fall and upper extremity muscle strength in older women. A convenience sample of 68 older women (70 (8) yrs) performed three trials of a simulated forward fall. Percentage joint moments of the upper extremity were recorded. Upper extremity muscle strength was collected via handgrip, hand-held dynamometry of the shoulder and elbow and a custom multi-joint concentric and eccentric strength isokinetic dynamometer protocol. Percentage joint moment contributions differed between women in their sixties and seventies with significantly greater relative shoulder joint involvement (P =.008), coupled with lower elbow joint contributions (P =.004) in comparison to 80 year olds. An increase in each year of age was associated with a 4% increase in elbow contribution (Beta = -0.421, r2 = 17.9, P = 0.0001) and a 3.7% decrease in shoulder contribution (Beta = 0.373, r2 = 14.6, P = 0.002). Older women exhibit different landing strategies as they age. Fall injury prevention research should consider interventions focused on these differences taking into account the contributions of upper extremity strength.

Blood Pressure and Heart Rate Responses to an Isokinetic Testing Protocol in Professional Soccer Players.

The aim of this study was to determine blood pressure (BP) and heart rate (HR) responses triggered during an isokinetic testing protocol in professional soccer players and compare cardiovascular parameters at completion of this isokinetic protocol with those during a treadmill test. Using purposive sampling, 63 professional soccer players were recruited. Cardiovascular responses were measured noninvasively during a bilateral testing protocol of knee flexion and extension. Treadmill ergospirometry following an incremental speed protocol was performed to analyze the same cardiovascular parameters at rest and at completion of this test. There were significant differences in diastolic blood pressure (DBP) and HR according to field position. The parameters presented high homogeneity at both competitive levels. Systolic blood pressure, mean arterial pressure, HR, and rate pressure product at completion of the treadmill test were significantly higher than those at completion of the isokinetic protocol. Intermittent isokinetic testing protocol of the knee triggers normal and safe BP and HR responses in healthy professional soccer players. The HR of the defenders was higher than those of the forwards and midfielders but was independent of the competitive level. The values of cardiovascular parameters at isokinetic protocol completion were lower than those during the treadmill test.

Isokinetic hamstring and quadriceps strength interpretation guideline for football (soccer) players with ACL reconstruction: a Delphi consensus study in the Netherlands

ABSTRACT Strength testing is a key part of rehabilitation and return to sport (RTS) decision making for football players after anterior cruciate ligament reconstruction (ACLR). Isokinetic testing has been the gold standard for strength measurement for decades, but a uniform protocol and clinical implications of test results are lacking. Therefore, this study aimed to 1) develop a uniform protocol for football players based on knowledge and experience from experts in the field of ACL rehabilitation and 2) clarify the clinical interpretation of different isokinetic test outcomes. In a structured Delphi consensus procedure 42 experts (98% full response rate) fulfilled three rounds that involved a survey, content analysis and anonymised feedback report for each round. Surveys addressed the isokinetic protocol, evaluation report and torque–angle curve of the isokinetic test for strength evaluation in football players after ACLR. The final protocol consisted of concentric knee flexion and extension isokinetic testing with 5 repetitions at 60°/sec, 20 repetitions at 180°/sec and 15 repetitions at 300°/sec and 60 seconds rest between sets. All parameters were deemed valuable, with Peak Torque, Max Rep Total Work, Total Work, Range of Motion and Agonist to Antagonist ratio being considered key for clinical interpretation. For qualitative assessment, it was advised to assess the shape, course, volume, potential dips, peak, and build-up to the peak of the parabola. This Delphi consensus study provided a guideline for data collection and clinical interpretation of isokinetic strength testing in football players after ACLR.

Effect of eccentric and concentric contraction mode on myogenic regulatory factors expression in human vastus lateralis muscle.

Skeletal muscle contractions are caused to release myokines by muscle fiber. This study investigated the myogenic regulatory factors, as MHC I, IIA, IIX, Myo-D, MRF4, Murf, Atrogin-1, Decorin, Myonection, and IL-15 mRNA expression in the response of eccentric vs concentric contraction. Eighteen healthy men were randomly divided into two eccentric and concentric groups, each of 9 persons. Isokinetic contraction protocols included maximal single-leg eccentric or concentric knee extension tasks at 60°/s with the dominant leg. Contractions consisted of a maximum of 12 sets of 10 reps, and the rest time between each set was 30s. The baseline biopsy was performed 4 weeks before the study, and post-test biopsies were taken immediately after exercise protocols from the vastus lateralis muscle. The gene expression levels were evaluated using Real-Time PCR methods. The eccentric group showed a significantly lower RPE score than the concentric group (P ≤ 0.05). A significant difference in MyoD, MRF4, Myonection, and Decorin mRNA, were observed following eccentric or concentric contractions (P ≤ 0.05). The MHC I, MHC IIA, IL-15 mRNA has been changed significantly compared to the pre-exercise in the concentric group (P ≤ 0.05). While only MHC IIX and Atrogin-1 mRNA changed significantly in the eccentric group (P ≤ 0.05). Additionally, the results showed a significant difference in MyoD, MRF4, IL-15, and Decorin at the follow-up values between eccentric or concentric groups (P ≤ 0.05). Our findings highlight the growing importance of elucidating the different responses of muscle growth factors associated with a myogenic activity such as MHC IIA, Decorin, IL-15, Myonectin, Decorin, MuRF1, and MHC IIX mRNA in following various types of exercise.