Relationship Between Knee Frontal Plane Projection Angle and Lower Limb Muscle Activity in Female Athletes.

CONTEXT: Anterior cruciate ligament injuries are directly related to the control of dynamic knee valgus in the landing of a jump, and this is mainly due to the correct activation and neuromuscular function of the lower-extremity muscles. The aim of the study is to assess the relationship between lower limb muscle activity during a single-legged drop jump and knee frontal plane projection angle (FPPA). DESIGN: A correlation study. METHODS: Thirty healthy collegiate female athletes were included in the study. Main outcomes measures were peak knee FPPA and muscle activity (% of maximal voluntary isometric contraction). Peak knee FPPA during a single-legged drop jump test was identified using a 2-dimensional motion analysis system. Muscle activity was assessed using a surface electromyograph for gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius, and lateral gastrocnemius. All variables were assessed for both dominant and nondominant limbs. A correlation analysis between peak knee FPPA and muscle activity was performed. Statistical significance was set at P <.05. RESULTS: A mean peak knee FPPA of 14.52° and 13.38° was identified for dominant and nondominant limb single-legged drop jump test, respectively. Muscle activity (% of maximal voluntary isometric contraction) for muscles assessed ranged from 43.97% to 195.71% during the single-legged drop jump test. The correlation analysis found no significant correlation between any of the muscles assessed and peak knee FPPA during the single-legged drop jump test (Pearson coefficient between -.3 and .1). CONCLUSIONS: There is no association between muscle activity from the lower limb muscles and the knee FPPA during a single-legged drop jump in female athletes. Thus, different muscle properties should be assessed in order to understand such an important movement as the knee FPPA during a jump.

Quadriceps and gluteus medius activity during stable and unstable loading exercises in athletes. A cross-sectional study.

The aim of this study was to evaluate the muscle activation of the vastus medialis, vastus lateralis, and gluteus medius during different strength and stability exercises with a water tank compared with a sandbag. A cross-sectional study was conducted in the Functional Anatomy Laboratory, and the sample consisted of 28 athletes. The main outcome measures were surface electromyography (dependent variable), water tank and sandbag, and exercise type (independent variables): Isometric Single Leg Stance (ISLS), One Leg Deadlift (OLDL), Front Rack Forward Lunge (FRFL), and Lateral Lunge (LL). Repeated measures analysis of variance (ANOVA) revealed a significant Group × Time interaction in gluteus medius root mean square (RMS) (F = 14.198, p < 0.001, ŋ2 = 0.35), vastus lateralis RMS (F = 24.374, p < 0.001, ŋ2 = 0.47), and vastus medialis RMS (F = 27.261, p < 0.001, ŋ2 = 0.50). In the between-group analysis, statistically significant differences were observed in gluteus medius RMS in the ISLS: 28.5 ± 15.8 water tank and 20.8 ± 12.6 sandbag (p < 0.001, ŋ2 = 0.08) and OLDL: 29.7 ± 13.3 water tank and 26.5 ± 13.1 sandbag (p < 0.001, ŋ2 = 0.01). In vastus lateralis in ISLS: 30.4 ± 37.6 water tank and 19.0 ± 26.7 sandbag (p < 0.001, ŋ2 = 0.03). In vastus medialis in ISLS: 14.2 ± 13.0 water tank and 7.0 ± 5.6 sandbag (p < 0.001, ŋ2 = 0.12), OLDL: 21.5 ± 16.9 water tank and 15.5 ± 10.7 sandbag (p = 0.002, ŋ2 = 0.04), and LL: 51.8 ± 29.6 water tank and 54.3 ± 29.3 sandbag (p = 0.017, ŋ2 = 0.00). These results confirm significantly greater activation of the gluteus medius and vastus medialis in the ISLS and OLDL exercises, and of the vastus lateralis in the water tank ISLS exercise. However, the vastus medialis shows greater activation in the LL exercise.

High-Intensity Interval Training (HIIT) on Biological and Body Composition Variables in Patients with Musculoskeletal Disorders: A Systematic Review and Meta-Analysis.

In order to assess the impact of high-intensity interval training (HIIT) on biological and body composition variables in patients with musculoskeletal disorders (MSKD), a systematic search on PubMed (Medline), CENTRAL, CINAHL, Web of Science, SPORTDiscus, and Scopus was conducted. Standardized mean differences (SMD) and 95% confidence intervals were calculated and pooled in a meta-analysis using the random-effects model. The effectiveness of HIIT on waist circumference, muscle mass, resting heart rate, resting systolic and diastolic blood pressure, C-reactive protein, body weight, and body fat were determined. GRADE, risk of bias 2, and PEDro scales were employed. HIIT compared to no intervention, minimal intervention, or usual care did not show significant results in its favor on any of the variables studied, except for the resting heart rate when compared with no intervention (SMD = -0.33; 95% CI: -0.63, -0.04; heterogeneity Q value: 0.14; p = 0.93; I2 = 0%). In addition, HIIT also does not seem to be more effective than moderate-intensity continuous training. Based on the results, it seems that HIIT has almost no significant effects on biological and body composition variables, except for resting heart rate, in patients with MSKD.

Effects of Adding an Online Exercise Program on Physical Function in Individuals Hospitalized by COVID-19: A Randomized Controlled Trial.

The worldwide pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has impacted all healthcare systems. One potential sequela experienced by hospitalized coronavirus disease 2019 (COVID-19) survivors includes muscle weakness with a reduction in strength and, consequently, a possible increase in frailty. The aim of this clinical trial was to evaluate the efficacy of adding an online therapeutic exercise program for 8 weeks to the medical prescriptions on functional variables in patients hospitalized due to COVID-19. A randomized controlled trial including 70 previously hospitalized COVID-19 survivors was conducted. Patients were randomly allocated to an experimental (n = 35) or control (n = 35) group. Both groups received regular prescriptions provided by their medical doctors. The experimental group also received a live online therapeutic exercise program for 8 weeks (3 sessions/week). Handgrip strength, gait speed, lower-extremity strength, balance, and frailty were assessed at baseline, at the end of the program, and one month after the end of the intervention. The repeated measures analysis of variance revealed significant Group*Time interactions for all the outcomes: (handgrip dominant: F = 17.395, p < 0.001, η2 = 0.24; handgrip non-dominant: F = 33.197, p < 0.001, η2 = 0.33; 4 m walk test (4WT): F = 13.039, p = 0.001, η2 = 0.16; short physical performance battery (SPPB): F = 26.421, p < 0.001, η2 = 0.28; the five chair-raise test (5CRT): F = 5.628, p = 0.004, η2 = 0.08; FRAIL scale: F = 11.249, p = 0.001, η2 = 0.14): patients in the experimental group experienced greater improvements in all outcomes than those assigned to the control group. This study revealed that the addition of an online exercise program for 8 weeks obtained greater improvements in handgrip strength, gait speed, lower-extremity strength, balance, and frailty in a sample of previously hospitalized COVID-19 survivors than application of just usual medical prescription.

Effectiveness of a Multicomponent Training Program on Physical Performance and Muscle Quality in Older Adults: A Quasi-Experimental Study.

Aging is associated with a decrease in functional capacity, manifested by a loss of strength, physical performance and muscle quality. Multicomponent training (MCT), characterized by the combination of at least three types of training, could be a good strategy to counteract these changes. To date there are no studies evaluating the effectiveness of MCT in improving both physical performance and muscle quality simultaneously. The aim of this study is to evaluate the changes produced by an MCT program on both physical performance and muscle quality in a population of healthy older adults. Sixteen healthy older adults were recruited to perform a 15-session multicomponent training intervention. Physical performance was assessed by different functional tests, and muscle quality was assessed by tensiomyography and myotonometry. The main results of this study show some improvement in functional tests, but not in muscle quality parameters, except for vastus lateralis stiffness. MCT is able to generate improvements in the physical performance of older adults, but these improvements are not reflected in muscle quality parameters measured by tensiomyography and myotonometry.

Relationship between lower limb EMG activity and knee frontal plane projection angle during a single-legged drop jump.

OBJECTIVES: To assess a relationship between lower limb muscle activity and the frontal plane knee kinematics during a single-legged drop jump. DESIGN: Correlation study; SETTING: Functional Anatomy Laboratory. PARTICIPANTS: 35 healthy collegiate male athletes. MAIN OUTCOME MEASURES: Muscle activity (%MVIC) of gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius and lateral gastrocnemius; peak knee frontal plane projection angle; and Pearson's correlation coefficients between muscle activity and peak knee frontal plane projection angle. All outcomes were assessed for both dominant and non-dominant limbs. RESULTS: Significant correlations (r = 0.46-0.60, P < 0.05) were found between the muscle activities of the gluteus maximus, gluteus medius, biceps femoris, and semitendinosus, when compared to the knee frontal plane projection angle. CONCLUSION: Gluteal muscles and hamstring muscles are associated with the peak knee frontal plane projection angle during a single-legged drop jump test. Thus, gluteal and hamstring muscle activities should be considered when developing rehabilitation or injury prevention programs.

Biceps Femoris Activation during Hamstring Strength Exercises: A Systematic Review.

BACKGROUND: The aim of the study was to systematically evaluate the biceps femoris long head activation across cross-sectional hamstring strength exercise studies. METHODS: A systematic review design was followed. The search strategy conducted in PubMed, Cochrane Library, and Web of Sciences databases found a total of 3643 studies. Once inclusion and exclusion criteria were applied, 29 studies were finally included in this systematic review. A total of 507 participants and 114 different exercises were analyzed. Exercises were evaluated individually and grouped into several categories: Nordics, isokinetic exercises, lunges, squats, deadlifts, good mornings, hip thrusts, bridges, leg curls, swings, hip and back extensions, and others. RESULTS: Results showed the isokinetic and Nordic exercises as the categories with highest biceps femoris activation (>60% of Maximal Voluntary Isometric Contraction). Nordic hamstring exercise ankle dorsiflexion was the exercise that achieved the highest biceps femoris long head activation (128.1% of its Maximal Voluntary Isometric Contraction). CONCLUSIONS: The results from this systematic review suggest that isokinetic and Nordic exercises seem to be the best option to activate biceps femoris long head. Future studies evaluating the implementation of these exercises in prevention programs are needed.

Normative data and correlation between dynamic knee valgus and neuromuscular response among healthy active males: a cross-sectional study.

The dynamic knee valgus (DKV) during different sport maneuvers has been widely described as risk factor to develop an anterior cruciate ligament injury. Hip and knee muscles seem to have a crucial role to prevent the dynamic knee valgus. This study aimed to give normative and correlational data about DKV and hip and knee neuromuscular response (NMR) among healthy active males. The hypothesis is that DKV could be correlated with hip NMR. A cross-sectional correlational study. Research Anatomy Laboratory. The study was carried out among 50 active, non-injured males. Dynamic Knee-Valgus angle and lower limb posterior chain muscles Neuromuscular Response. DKV was measured using Kinovea software during a Single-Legged Drop Jump test and NMR was measured using tensiomyography and myotonometry for gluteus maximum, biceps femoris, semitendinosus, lateral and medial gastrocnemius. Right and left limbs were both performed and analyzed independently. No significant correlation was observed between DKV and hip and knee muscles NMR. This study shows normative and correlational data about dynamic knee valgus, tensiomyography and myotonometry for healthy and active males. The DKV control seems to be non-correlated with isolated hip and knee muscles NMR so this suggests it is more about Central Nervous System activity than about isolated muscles NMR.

Effect of a brief progressive resistance training program in hospital porters on pain, work ability, and physical function.

BACKGROUND: Hospital porters are possibly exposed to the greatest mechanical loads within the hospital environment. However, the evidence about preventive strategies in this population is scarce. OBJECTIVE: To investigate the effect of a workplace-based progressive resistance-training program on musculoskeletal pain among hospital porters. METHOD: A total of 37 hospital porters (27 women, 10 men) participated. Participants allocated to the intervention group performed five brief resistance training sessions/week, for 9 weeks during working hours at the hospital. Intensity was progressively increased. Participants allocated to the control group maintained their usual physical activity. The primary outcome was pain assessed with the patient global impression of pain change scale. Secondary outcome measures were average pain intensity, work ability, use of analgesics, and physical function. Additionally, perceived general changes were evaluated at follow-up: wellness, satisfaction at work, desire to exercise, motivation to eat healthy, energy to be with family and friends, and socialization with colleagues. RESULTS: For the primary outcome, the intervention group showed lower general pain (p < 0.0001) and greater wellbeing (p < 0.0001), work satisfaction (p = 0.0048), desire for practicing exercise (p = 0.0007), and energy (p = 0.0474) compared with the control group. Significant between-group interactions were found for work impairment due to diseases (d = -1.2), hips/thighs pain (d = 0.7), ankles/feet pain (d = 0.4), the Biering-Sorensen test (d = -0.6) and the push-ups test (d = -2.3) favoring the intervention group. All between-group differences were clinically important. CONCLUSION: A progressive resistance training program performed at the workplace is feasible and effective in reducing musculoskeletal pain and improving work ability and physical function among hospital porters.

Professional experience, work setting, work posture and workload influence the risk for musculoskeletal pain among physical therapists: a cross-sectional study.

PURPOSE: Physical therapists (PTs) have a high risk of developing musculoskeletal pain (MP) due to the physically demanding nature of their work tasks. Experience or the specialty area, have been associated with MP, however, previous studies are few and small. The aim of this study was to investigate the association between work-related factors and MP among PTs. METHODS: In this cross-sectional study, we collected information about MP and work-related factors of 1006 PTs using an online questionnaire. Associations between various work-related factors and MP were modelled using logistic regression controlled for various confounders. RESULTS: Neck (57%) and low back pain (49%) were most common. Work-related factors associated with higher risk for having moderate-to-high MP (≥ 3 on a scale of 0-10) were "treating more patients at the same time" [OR 2.14 (95% CI 1.53-2.99)], "working ≥45 h per week" [OR 1.73 (95% CI 1.05-2.84)], and "work in a seated position" [OR 2.04 (95% CI 1.16-3.57)] for the low back. "More years of experience" showed a negative association for elbow pain [OR 0.41 (95% CI 0.21-0.78)] and low back pain [OR 0.48 (95% CI 0.29-0.79)] compared with their less experienced counterparts. CONCLUSIONS: The lack of professional experience, working in private clinics, working in a seated position and high workload are associated with the higher risk for MP among PTs. These results add further insight about the relevance of such factors, which might be considered for developing effective interventions to prevent work-related MP and better working conditions among PTs.

Tolerability and Muscle Activity of Core Muscle Exercises in Chronic Low-back Pain.

Most of the studies evaluating core muscle activity during exercises have been conducted with healthy participants. The objective of this study was to compare core muscle activity and tolerability of a variety of dynamic and isometric exercises in patients with non-specific low back pain (NSLBP). 13 outpatients (average age 52 years; all with standing or walking work in their current or latest job) performed 3 consecutive repetitions at 15-repetition maximum during different exercises in random order. Surface electromyography was recorded for the rectus abdominis; external oblique and lumbar erector spinae. Patients rated tolerability of each exercise on a 5-point scale. The front plank with brace; front plank and modified curl-up can be considered the most effective exercises in activating the rectus abdominis; with a median normalized EMG (nEMG) value of 48% (34-61%), 46% (26-61%) and 50% (28-65%), respectively. The front plank with brace can be considered the most effective exercise in activating the external oblique; with a nEMG of 77% (60-97%). The squat and bird-dog exercises are especially effective in activing the lumbar erector spinae; with nEMG of 40% (24-87%) and 29% (27-46%), respectively. All the exercises were well tolerated; except for the lateral plank that was mostly non-tolerated. In conclusion; the present study provides a variety of dynamic and isometric exercises; where muscle activity values and tolerability can be used as guide to design evidence-based exercise programs for outpatients with NSCLBP.

Which Seems to Be Worst? Pain Severity and Quality of Life between Patients with Lateral Hip Pain and Low Back Pain.

Purpose: The aim of this study was to compare the pain severity, health-related quality of life (HRQoL), and risk of continue having pain with prognostic risk scores (PRS), between patients referring greater trochanteric pain syndrome (GTPS) and chronic low back pain (CLBP). Methods: A descriptive, cross-sectional design using nonprobability convenience sampling was performed. A total sample of 102 patients were recruited from two primary health-care centers and divided into GTPS (n = 51) and CLBP (n = 51) groups. The primary outcome was pain severity which was assessed with the Spanish version of the Graded Chronic Pain Scale (GCPS). The secondary outcome was the HRQoL which was measured using the Spanish version of EuroQoL Five Dimensions and Five Levels (EQ-5D-5L) as well as the PRS. Results: Significant differences (P<0.05) were found within both groups in the pain severity global score with a medium effect size showing greater values for the CLBP group with regards to the GTPS group. The PRS in both groups did not show statistical differences (P>0.05). Nevertheless, subjects referring CLBP showed greater levels in the PRS than patients with GTPS. Comparing both groups, the HRQoL showed statistical differences (P<0.05) in the "pain/discomfort" domain in the CLBP group with respect to the GTPS group, but not in the other domains. Conclusions: Patients who suffered from CLBP showed greater pain severity and HRQoL discomfort with regard to patients with GTPS. Despite greater scores for CLBP, the PRS did not seem to be different between both conditions.

Fear Avoidance Beliefs and Risk of Long-Term Sickness Absence: Prospective Cohort Study among Workers with Musculoskeletal Pain.

BACKGROUND AND OBJECTIVE: Musculoskeletal pain is common in the population. Negative beliefs about musculoskeletal pain and physical activity may lead to avoidance behavior resulting in absence from work. The present study investigates the influence of fear avoidance beliefs on long-term sickness absence. METHODS: Workers of the general working population with musculoskeletal pain (low back, neck/shoulder, and/or arm/hand pain; n = 8319) from the Danish Work Environment Cohort Study were included. Long-term sickness absence data were obtained from the Danish Register for Evaluation and Marginalization (DREAM). Time-to-event analyses (cox regression) controlled for various confounders estimated the association between fear avoidance beliefs (very low, low, moderate [reference category], high, and very high) at baseline and long-term sickness absence (LTSA; ≥6 consecutive weeks) during a 2-year follow-up. RESULTS: During the 2-year follow-up, 10.2% of the workers experienced long-term sickness absence. In the fully adjusted model, very high-level fear avoidance increased the risk of LTSA with hazard ratio (HR) of 1.48 (95% CI 1.15-1.90). Similar results were seen analyses stratified for occupational physical activity, i.e., sedentary workers (HR 1.72 (95% CI 1.04-2.83)) and physically active workers (HR 1.48 (95% CI 1.10-2.01)). CONCLUSION: A very high level of fear avoidance is a risk factor for long-term sickness absence among workers with musculoskeletal pain regardless of the level of occupational physical activity. Future interventions should target fear avoidance beliefs through information and campaigns about the benefits of staying active when having musculoskeletal pain.