Analysis of pain relief and functional recovery in patients with rotator cuff tendinopathy through therapeutic ultrasound and photobiomodulation therapy: a comparative study.

This study aimed to compare shoulder tendinopathy treatment with therapeutic ultrasound combined with LED photobiomodulation therapy using LED-infrared (850 nm) or LED-red (640 nm). The study assessed 75 patients, aged 45 to 70 years, distributed into five experimental groups (15 patients each): therapeutic ultrasound (US), infrared light irradiation (IR), visible red light irradiation (VR), infrared light and ultrasound combined (IR-US), and red light in conjunction with ultrasound (VR-US). The ultrasound parameters are 1 MHz, 0.5 W/cm2 (SATA), and 100 Hz repetition rate, applied for 4 min each session. LED irradiation protocols were as follows: 3 points, 7.5 J per point, IR-LED 750 mW, 10 s, VR-LED 250 mW, 30 s. LED irradiation is followed by ultrasound in the combined therapies. The efficiency of the five therapies was evaluated assessing 12 parameters: quality of life (Health Assessment Questionnaire, HAQ), pain intensity (Visual Analog Scale, VAS), articular amplitude of shoulder movement (flexion, extension, abduction, adduction, medial rotation, lateral rotation), muscle strength (abduction, lateral rotation), and electromyography (lateral rotation, abduction). Treatments comprised 12 sessions for 4 weeks. Intra-group analysis showed that the five therapies significantly improved the recovery of all parameters after treatment. Regarding the comparison of irradiated therapies and ultrasound, statistical analysis showed that IR-US was a better treatment than US for all 12 parameters. IR treatment exceeded US on 9 items, whereas that VR and VR-US therapies exceeded US in 7 and 10 parameters, respectively (p < 0.05). Because of that, IR-US shows to be the best treatment for rotator cuff tendinopathy. In conclusion, improvements in quality of life, pain intensity relief, shoulder amplitude motion, and muscle strength force obtained with ultrasound therapy are enhanced by adding infrared LED irradiation to ultrasound for patients suffering from rotator cuff tendinopathy. This study was registered with the Brazilian Registry of Clinical Trials (ReBEC) under Universal Trial Number (UTN) U1111-1219-3594 (2018/22/08).

The effect of inherent and incidental constraints on bimanual and social coordination.

The current investigation was designed to examine the influence of inherent and incidental constraints on the stability characteristics associated with bimanual and social coordination. Individual participants (N = 9) and pairs of participants (N = 18, 9 pairs) were required to rhythmically coordinate patterns of isometric forces in 1:1 in-phase and 1:2 multi-frequency patterns by exerting force with their right and left limbs. Lissajous information was provided to guide performance. Participants performed 13 practice trials and 1 test trial per pattern. On the test trial, muscle activity from the triceps brachii muscles of each arm was recorded. EMG-EMG coherence between the two EMG signals was calculated using wavelet coherence. The behavioral data indicated that individual participants performed the 1:1 in-phase pattern more accurately and with less variability than paired participants. The EMG coherence analysis indicated significantly higher coherence for individual participants than for the paired participants during the 1:1 in-phase pattern, whereas no differences were observed between groups for the 1:2 coordination pattern. The results of the current investigation support the notion that neural crosstalk can stabilize 1:1 in-phase coordination when contralateral and ipsilateral signals are integrated via the neuromuscular linkage between two effectors.

Age-associated differences in motor output variability and coordination during the simultaneous dorsiflexion of both feet.

Older adults are more variable than young adults on tasks that demand the simultaneous control of more than one effector, and the difference between age groups may be related to their different capacity of coordinating the force output of the involved effectors. The goal of this study was to determine whether age-associated differences in motor output variability during tasks involving the simultaneous dorsiflexion of two feet can be partially explained by differences in coordination and possibly attenuated by physical training. Ten young and 22 old adults (10 trained and 12 untrained old adults) volunteered to participate in the study. Trained older adults had experience in a high-intensity mixed modality training (MMT) regime for a minimum of 1 year. Volunteers performed successive trials of a constant force task and a goal-directed task, with and without visual feedback. Within- and between-trial variability were calculated and coordination was quantified using the uncontrolled manifold (UCM) approach (i.e., co-variation of the force outputs of both feet were used to quantify a motor synergy index). Older adults exhibited greater variability and lower synergy (p < .05), independently of physical training status, than young adults. Removal of visual feedback caused greater variability and lower synergy for all groups (p < .05). Our results suggest that older adults exhibit greater motor output variability in tasks involving the simultaneous dorsiflexion of both feet possibly due to a lack of coordination between the feet.

Pilates and Proprioceptive Neuromuscular Facilitation Methods Induce Similar Strength Gains but Different Neuromuscular Adaptations in Elderly Women.

Background/Study Context: The aging process is associated with a decline in muscle mass, strength, and conditioning. Two training methods that may be useful to improve muscle function are Pilates and proprioceptive neuromuscular facilitation (PNF). Thus, the present study aimed to compare the influence of training programs using Pilates and PNF methods with elderly women. METHODS: Sixty healthy elderly women were randomly divided into three groups: Pilates group, PNF group, and control group. Pilates and PNF groups underwent 1-month training programs with Pilates and PNF methods, respectively. The control group received no intervention during the 1 month. The maximal isometric force levels from knee extension and flexion, as well as the electromyography (EMG) signals from quadriceps and biceps femoris, were recorded before and after the 1-month intervention period. RESULTS: A two-way analysis of variance revealed that the Pilates and PNF methods induced similar strength gains from knee flexors and extensors, but Pilates exhibited greater low-gamma drive (i.e., oscillations in 30-60 Hz) in the EMG power spectrum after the training period. CONCLUSIONS: These results support use of both Pilates and PNF methods to enhance lower limb muscle strength in older groups, which is very important for gait, postural stability, and performance of daily life activities.

Low intensity laser and LED therapies associated with lateral decubitus position and flexion exercises of the lower limbs in patients with lumbar disk herniation: clinical randomized trial.

UNLABELLED: The objective of this study is to evaluate the effectiveness of laser and LED therapies, associated with lateral decubitus position and flexion exercises of the lower limbs in patients with lumbar disk herniation (LDH). It is a randomized blinded clinical trial. Fifty-four subjects with LDH L4-L5 and L5-S1 were selected and randomly allocated into groups: laser 904 nm, placebo, and LED 945 nm. The numbers of subjects for each group that completed the treatment were 18, 13, and 18, respectively. Twelve points over the lumbar spine region (L2 to S1) and eight points on the injured thigh in the path of the lumbar roots L5 and S1 were irradiated. Irradiation parameters for each point were as follows: laser wavelength 904 ± 10 nm, average power 0.038 ± 20 % W, irradiated area 0.16 cm(2), energy per point 4 J, and treatment time per point 104 s; LED wavelength 945 ± 15 nm, power 0.1 W, irradiated area 1.0cm(2), energy per point 4 J, and treatment time per point 40 s. Lateral decubitus opposite to the side of the radicular was the standard position for all patients. After phototherapy and laser placebo sessions, the subjects performed sequences of flexion exercises of the lower limbs (ten per session) for 15 daily sessions. VARIABLES STUDIED: pain intensity assessed by visual analog scale (VAS), degree of flexion of the affected hip measured by the universal goniometer and functional capacity assessed by the Oswestry Disability Index. The three groups had statistically significant improvement in lumbar and radicular pain, in hip mobility, and in the functional disability index (p ≤ 0.001). There was a statistically significant difference (p = 0.024) in radicular pain between the groups, gait claudication and Oswestry Disability Index. We can conclude that in the treatment of L4-L5 and L5-S1 LDH with radiculopathy, LED, associated with lateral decubitus position and flexion exercises of the lower limbs, showed better therapeutic performance for radicular pain, gait claudication, and functional disability.

Effects of two exercise protocols on postural balance of elderly women: a randomized controlled trial.

BACKGROUND: The aging process reduces both sensory capabilities and the capabilities of the motor systems responsible for postural control, resulting in a high number of falls among the elderly. Some therapeutic interventions can directly interrupt this process, including physical exercise. This study compares and examines the effects of two exercise protocols on the balance of elderly women. METHODS: Elderly women who participated in a local church project (n = 63) were randomly divided into three groups: the proprioceptive neuromuscular facilitation group (PNFG), Pilates group (PG), and control group (CG). Of the 63 women, 58 completed the program. A training program involving 50-min sessions was performed in the PNFG and PG three times a week for 4 weeks. The elderly women in the CG received no intervention and continued with their daily activities. Stabilometric parameters, the Berg Balance Scale score, functional reach test, and timed up and go test (TUG test) were assessed before and 1 month after participation. RESULTS: In the comparison among groups, the women in the PNFG showed a significant reduction in most of the stabilometric parameters evaluated and better Berg Balance Scale score, functional reach test result, and TUG test result than did women in the CG (p < 0.05). Women in the PG showed significantly better performance on the functional reach test and TUG test than did women in the CG (p < 0.05). CONCLUSIONS: Women in the PNFG showed significantly better static and dynamic balance than did women in the CG. Women in the PG also showed better dynamic balance than did women in the CG. However, no significant differences were observed in any of the balance variables assessed between the PNFG and PG. TRIAL REGISTRATION: clinicaltrials.gov, number NCT02278731.

Harnessing Voice Analysis and Machine Learning for Early Diagnosis of Parkinson's Disease: A Comparative Study Across Three Datasets.

OBJECTIVE: This study evaluates the efficacy of voice analysis combined with machine learning (ML) techniques in enabling the diagnosis of Parkinson's disease (PD). METHODS: Voice data, phonation of the vowel "a," from three distinct datasets (two from the University of California Irvine ML Repository and one from figshare) for 432 participants (278 PD patients) were analyzed. We employed four ML models-Artificial Neural Networks, Random Forest, Gradient Boosting (GB), and Support Vector Machine (SVM)-alongside two ensemble methods (soft voting classifier-Ensemble Voting Classifier and stacking method-Ensemble Stacking Model (ESM)). The models underwent 50 iterations of evaluation, involving various data splits and 10-fold cross-validation. Comparative analysis was done using one-way Analysis of Variance followed by Bonferroni posthoc corrections. RESULTS: The ESM, SVM, and GB models emerged as the top performers, demonstrating superior performance across metrics, including accuracy, sensitivity, specificity, precision, F1 score, and area under the receiver operating characteristic curve (ROC AUC). Despite data heterogeneity and variable selection limitations, the models showed high values for all metrics. CONCLUSIONS: ML integration with voice analysis, mainly through ESM, SVM, and GB, is promising for early PD diagnosis. Using multi-source data and a large sample size enhances our findings' validity, reliability, and generalizability. SIGNIFICANCE: Integrating advanced ML techniques with voice analysis demonstrates substantial potential for improving early PD detection, offering valuable tools for speech-language pathologists (SLPs). These findings provide clinically relevant insights that can be applied within the scope of SLP practice to refine diagnostic processes and facilitate early intervention.

Tourniquets, types and techniques in emergency prehospital care: A narrative review.

Massive uncontrolled hemorrhage is an important cause of preventable death in trauma. Therefore, applying an arterial tourniquet (TQ) is recommended as a pre-hospital measure to control bleeding after severe traumatic bleeding. Limb TQ applies circumferential compression proximally to the injury site to compress the arteries, resulting in blood flow and consequently hemorrhage interruption. The use of commercial tourniquets (C-TQ), which are designed, tested, and registered to control hemorrhages in pre-hospital care, is a consensus. However, they are still uncommon in many prehospital emergency services and the overall level of evidence in most studies is low. This narrative review aimed to characterize the importance of tourniquets use in prehospital emergency care and its application techniques. Furthermore, it proposes to stimulate the development of new devices, more accessible and easier to use, to suggest new directions of studies and medical education demands, with manikin and simulation development.

Proposing Clinicopathological Staging and Mitotic Count as Prognostic Factors for Canine Soft Tissue Sarcomas.

Soft tissue sarcomas (STSs) are a heterogeneous group of malignant mesenchymal tumors with similar histological features and biological behaviors. They are characterized by a low to moderate local recurrence rate and low metastasis, affecting approximately 20% of patients. Although this tumor set is vital in veterinary medicine, no previous unified staging system or mitotic count has been associated with patient prognosis. Therefore, this study proposed a new clinicopathological staging method and evaluated a cut-off value for mitosis related to the survival of dogs affected by STS. This study included 105 dogs affected by STS, treated only with surgery, and a complete follow-up evaluation. The new clinicopathological staging system evaluated tumor size (T), nodal involvement (N), distant metastasis (M), and histological grading criteria (G) to categorize the tumor stage into four groups (stages I, II, III, and IV). The proposed tumor staging system was able to differentiate patients' prognoses, with dogs with stage IV disease experiencing the lowest survival time and dogs with stage I disease having the highest survival time (p < 0.001). Moreover, we assessed the median mitosis (based on mitotic count) and its association with overall survival. Our study's median mitosis was 5, and patients with ≤5 mitoses had a higher survival time (p = 0.006). Overall, the proposed staging system and mitotic count seemed promising in the prediction of patient prognosis.

Long-term adaptations differ for shortening and lengthening contractions.

The purpose of this study was to determine whether practice of a sinusoidal task induces different neural adaptations for shortening and lengthening contractions performed within a task. Fourteen young adults were instructed to accurately match a sinusoidal target by lifting and lowering a light load (15% of 1 repetition maximum; 1-RM) with their index finger for 35 s. Each subject performed a total of 50 practice trials during the practice session. After 48 h, subjects performed five trials with the same sinusoidal target at each of three loading conditions: 15% (retention/savings), 7.5% (transfer to a lighter load), and 30% (transfer to a heavier load) of 1-RM. Movement error was quantified as the root mean square error of the movement trace from the target, while movement variability was quantified as the standard deviation of the acceleration of the index finger. First dorsal interosseus muscle activation was recorded using surface electromyography (EMG). The frequency structure of the acceleration and EMG signals were obtained using wavelets. Subjects were able to retain the trained task for both shortening and lengthening contractions; however, they exhibited better savings for the shortening contractions. Additionally, for the lowering segments of the task subjects exhibited better transfer to the lighter load. Short-term adaptation and transfer results may be related to changes in the agonist muscle neural activation. Finally, we found greater movement variability during lengthening contractions which was related to both the frequency structure of the acceleration and EMG signals.

Hand dominance during constant force isometric contractions: evidence of different cortical drive commands.

The purpose of this study was to investigate force variability and sensoriomotor strategies of dominant and nondominant hands of right and left-handed subjects during a submaximal isometric force production task. Twelve right-handed adults (9 men and 3 women; 23 ± 3 year) and twelve left-handed adults (4 men and 8 women; 24 ± 3 year) performed an isometric constant force contraction sustained at 30 and 50% of maximal force for 10 s. Surface EMG signals were obtained from forearm flexors and extensors. Force signals were analyzed in the time (CV of force) and frequency (0-10 Hz) domain. The neural activation of the involved muscles was investigated from the EMG structure using the cross-wavelet spectra of the interference EMG signals of six different frequency bands of the EMG signals were quantified (5-13, 13-30, 30-60, 60-100, 100-150 and 150-200 Hz). The major findings were: (1) dominant and nondominant hands of right- and left-handed subjects exhibited similar CV of force; (2) the power spectrum of force is influenced by handedness, with greater 1-3 Hz oscillations for left-handed subjects when compared to right-handed subjects; (3) right-handed subjects have greater 30-60 Hz neuromuscular activation when compared to left-handed subjects. Our results indicate that right-handed individuals may rely preferentially in visual feedback to carry out a task with visual and proprioceptive feedback because of the left hemisphere specialization on the visuomotor control.

Bayesian integration during sensorimotor estimation in elite athletes.

An experiment was designed to determine the effects of sensory uncertainty on sensorimotor estimation in elite athletes compared to non-athletes. Nineteen elite athletes and 16 non-athletes were required to estimate when and where a cursor arrived at a target location. The cursor position was displayed through its entire trajectory in the certain condition while only briefly in the uncertain condition. Accuracy and variability in time and spatial domains were calculated. A Bayesian analysis using subsets of subjects' total spatial variance was also performed. The results indicated that athletes and non-athletes used estimation strategies consistent with Bayesian integration. The results also showed a decrease in variability for spatial performance for both groups during the uncertain condition compared to the certain condition, especially when the cursor location was further away from the prior mean. This decrease in variability was significantly greater for non-athletes. By concentrating performance around the end-point mean location, an increase in spatial error occurred. More spatial and timing errors were observed in non-athletes than athletes, indicating athletes were more certain about likelihood information or their interpretation of likelihood information than non-athletes. These results suggest that athletic experience may facilitate the use of probabilistic information for optimal sensorimotor estimations.

The influence of distal and proximal muscle activation on neural crosstalk.

Previous research has indicated that neural crosstalk is asymmetric, with the dominant effector exerting a stronger influence on the non-dominant effector than vice versa. Recently, it has been hypothesized that this influence is more substantial for proximal than distal effectors. The current investigation was designed to determine the effects of distal ((First Dorsal Interosseous (FDI)) and proximal (triceps brachii (TBI)) muscle activation on neural crosstalk. Twelve right-limb dominant participants (mean age = 21.9) were required to rhythmically coordinate a 1:2 pattern of isometric force guided by Lissajous displays. Participants performed 10, 30 s trials with both distal and proximal effectors. Coherence between the two effector groups were calculated using EMG-EMG wavelet coherence. The results indicated that participants could effectively coordinate the goal coordination pattern regardless of the effectors used. However, spatiotemporal performance was more accurate when performing the task with distal than proximal effectors. Force distortion, quantified by harmonicity, indicated that more perturbations occurred in the non-dominant effector than in the dominant effector. The results also indicated significantly lower harmonicity for the non-dominant proximal effector compared to the distal effectors. The current results support the notion that neural crosstalk is asymmetric in nature and is greater for proximal than distal effectors. Additionally, the EMG-EMG coherence results indicated significant neural crosstalk was occurring in the Alpha bands (5-13 Hz), with higher values observed in the proximal condition. Significant coherence in the Alpha bands suggest that the influence of neural crosstalk is occurring at a subcortical level.

Rectification of the EMG signal impairs the identification of oscillatory input to the muscle.

Rectification of EMG signals is a common processing step used when performing electroencephalographic-electromyographic (EEG-EMG) coherence and EMG-EMG coherence. It is well known, however, that EMG rectification alters the power spectrum of the recorded EMG signal (interference EMG). The purpose of this study was to determine whether rectification of the EMG signal influences the capability of capturing the oscillatory input to a single EMG signal and the common oscillations between two EMG signals. Several EMG signals were reconstructed from experimentally recorded EMG signals from the surface of the first dorsal interosseus muscle and were manipulated to have an oscillatory input or common input (for pairs of reconstructed EMG signals) at various frequency bands (in Hz: 0-12, 12-30, 30-50, 50-100, 100-150, 150-200, 200-250, 250-300, and 300-400), one at a time. The absolute integral and normalized integral of power, peak power, and peak coherence (for pairs of EMG signals) were quantified from each frequency band. The power spectrum of the interference EMG accurately detected the changes to the oscillatory input to the reconstructed EMG signal, whereas the power spectrum of the rectified EMG did not. Similarly, the EMG-EMG coherence between two interference EMG signals accurately detected the common input to the pairs of reconstructed EMG signals, whereas the EMG-EMG coherence between two rectified EMG signals did not. The frequency band from 12 to 30 Hz in the power spectrum of the rectified EMG and the EMG-EMG coherence between two rectified signals was influenced by the input from 100 to 150 Hz but not from the input from 12 to 30 Hz. The study concludes that the power spectrum of the EMG and EMG-EMG coherence should be performed on interference EMG signals and not on rectified EMG signals because rectification impairs the identification of the oscillatory input to a single EMG signal and the common oscillatory input between two EMG signals.

Neural control of the lips differs for young and older adults following a perturbation.

Aging impairs the control of many skilled movements including speech. The purpose of this paper was to investigate whether young and older adults adapt to lower lip perturbations during speech differently. Twenty men (10 young, 26 ± 3 years of age; 10 older, 60 ± 9 years of age) were requested to repeat the word ("papa") 300 times. In 15% of the trials, the subjects experienced a mechanical perturbation on the lower lip. Displacement and neural activation (EMG) of the upper and lower lips were evaluated. Perturbations to the lower lip caused a greater increase in the maximum displacement of the lower lip for older adults compared with young adults (34.7 ± 19% vs. 13.4 ± 17%; P=0.017). Furthermore, young adults exhibited significantly greater 30-100 Hz normalized EMG power for the lower lip compared to the upper lip (P<0.005). In young adults, changes from normal to perturbed trials in the 30-50 Hz frequency band of the EMG were negatively correlated to the changes from normal to perturbed trials in the lower lip maximum displacement (R (2) =0.48; P=0.025). It is concluded that young adults adapt better to lower lip perturbations compared with older adults and that the associated neural activation strategy of the involved muscle is different for the two age groups.

Modeling the effects of intervention strategies on COVID-19 transmission dynamics.

OBJECTIVES: To model the effects of continuous, intermittent, and stepping-down social distancing (SD) strategies and personal protection measures on COVID-19 transmission dynamics. METHODS: Constant, intermittent, and stepping-down SD strategies were modeled at 4 mean magnitudes (5%, 10 %, 15 % and 20 %), 2 time windows (40-days, 80-days), and 2 levels of personal caution (30 % and 50 %). RESULTS: The stepping-down strategy was the best long-term SD strategy to minimize the peak number of active COVID-19 cases and associated deaths. The stepping-down strategy also resulted in a reduction in total time required to SD over a two-year period by 6.5 % compared to an intermittent or constant SD strategy. An 80-day SD time-window was statistically more effective in maintaining control over the COVID-19 pandemic than a 40-day window. However, the results were dependent upon 50 % of people being cautious (engaging in personal protection measures). CONCLUSION: If people exercise caution while in public by protecting themselves (e.g., wearing a facemask, proper hand hygiene and avoid agglomeration) the magnitude and duration of SD necessary to maintain control over the pandemic can be reduced. Our models suggest that the most effective way to reduce SD over a two-year period is a stepping-down approach every 80 days. According to our model, this method would prevent a second peak and the number of intensive care units needed per day would be within the threshold of those currently available.

Force, reaction time, and precision of Kung Fu strikes.

The goal was to compare values of force, precision, and reaction time of several martial arts punches and palm strikes performed by advanced and intermediate Kung Fu practitioners, both men and women. 13 Kung Fu practitioners, 10 men and three women, participated. Only the men, three advanced and seven intermediate, were considered for comparisons between levels. Reaction time values were obtained using two high speed cameras that recorded each strike at 2500 Hz. Force of impact was measured by a load cell. For comparisons of groups, force data were normalized by participant's body mass and height. Precision of the strikes was determined by a high speed pressure sensor. The results show that palm strikes were stronger than punches. Women in the study presented, on average, lower values of reaction time and force but higher values of precision than men. Advanced participants presented higher forces than intermediate participants. Significant negative correlations between the values of force and precision and the values of force and reaction time were also found.

Wavelet transform analysis of electromyography kung fu strikes data.

In martial arts and contact sports strikes are performed at near maximum speeds. For that reason, electromyography (EMG) analysis of such movements is non-trivial. This paper has three main goals: firstly, to investigate the differences in the EMG activity of muscles during strikes performed with and without impacts; secondly, to assess the advantages of using Sum of Significant Power (SSP) values instead of root mean square (rms) values when analyzing EMG data; and lastly to introduce a new method of calculating median frequency values using wavelet transforms (WMDF). EMG data of the deltoid anterior (DA), triceps brachii (TB) and brachioradialis (BR) muscles were collected from eight Kung Fu practitioners during strikes performed with and without impacts. SSP results indicated significant higher muscle activity (p = 0.023) for the strikes with impact. WMDF results, on the other hand, indicated significant lower values (p = 0. 007) for the strikes with impact. SSP results presented higher sensitivity than rms to quantify important signal differences and, at the same time, presented lower inter-subject coefficient of variations. The result of increase in SSP values and decrease in WMDF may suggest better synchronization of motor units for the strikes with impact performed by the experienced Kung Fu practitioners. Key PointsThe results show higher muscle activity and lower electromyography median frequencies for strikes with impact compared to strikes without.SSP results presented higher sensitivity and lower inter-subject coefficient of variations than rms results.Kung Fu palm strikes with impact may present better motor units' synchronization than strikes without.

The effects of height and distance on the force production and acceleration in martial arts strikes.

Almost all cultures have roots in some sort of self defence system and yet there is relatively little research in this area, outside of a sports related environment. This project investigated different applications of strikes from Kung Fu practitioners that have not been addressed before in the literature. Punch and palm strikes were directly compared from different heights and distances, with the use of a load cell, accelerometers, and high speed video. The data indicated that the arm accelerations of both strikes were similar, although the force and resulting acceleration of the target were significantly greater for the palm strikes. Additionally, the relative height at which the strike was delivered was also investigated. The overall conclusion is that the palm strike is a more effective strike for transferring force to an object. It can also be concluded that an attack to the chest would be ideal for maximizing impact force and moving an opponent off balance. Key PointsIt has been determined that the palm strike is more effective than the punch for developing force and for transferring momentum, most likely the result of a reduced number of rigid links and joints.A strike at head level is less effective than a strike at chest level for developing force and transferring momentum.Distance plays an effect on the overall force and momentum changes, and most likely is dependent on the velocity of the limb and alignment of the bones prior to impact.The teaching of self defence for novices and law enforcement would benefit from including the palm strike as a high priority technique.

Mixed Modal Training to Help Older Adults Maintain Postural Balance.

OBJECTIVE: Older adults have poorer balance compared with younger adults, but exercise may slow this age-related loss. Although the best type of exercise to optimize balance gains remains unclear, it is likely that a training regimen incorporating several different types of exercise, termed mixed modality training (MMT) (popularized by CrossFit), would be effective. Accordingly, this study aims to assess whether regular MMT leads to improved balance in older adults. METHODS: Ten trained young (28 ± 4 years, minimum of 1 year MMT) and 22 older (67 ± 6 years) adults participated in this study. Older adults were divided into 2 groups: trained (minimum of 1 year MMT) and untrained. An electronic baropodometer was used to assess baseline postural balance using the postural sway (both open and closed eyes) test. RESULTS: Compared with untrained older adults, those who trained performed similarly to young trained adults in the postural sway test. In addition, with eyes closed, trained older adults demonstrated better center of pressure total displacement area than untrained older adults. CONCLUSION: These data suggest that regular MMT can lead to a level of postural control in older adults similar to that observed in young adults. The favorable effects of MMT on postural control in older adults may be attributable to improvements in both muscle strength and proprioception.