Rotational kinematics of pelvis and upper trunk at butterfly stroke: Can fins affect the dynamics of the system?

Acute effect of dry needling on trunk kinematics and balance of patients with non-specific low back pain

BACKGROUND

Limited knowledge exists about the effectiveness of dry needling (DN) concerning the torso kinematics in patients with non-specific low back pain (NS-LBP). Acute effects of DN in NS-LBP patients from a functional perspective were investigated.

METHODS

Sixteen NS-LBP patients and 11 healthy individuals (HG) were examined. NS-LBP patients received a single session of DN at the lumbar region. Baseline and immediate post-treatment measurements during flexion-extension and lateral bending of the trunk were conducted for the NS-LBP patients. HG were measured only at baseline to be used as a reference of NS-LBP patients' initial condition. Algometry was applied in NS-LBP patients. Centre of pressure, range of motion of the trunk and its' derivatives were obtained.

FINDINGS

HG performed significantly faster, smoother and with greater mobility in the performed tasks compared to the pre intervention measurements of the NS-LBP patients. For the NS-LBP patients, significant greater angular velocity in frontal plane and significant lower jerk in the sagittal plane were demonstrated post intervention. DN alleviated pain tolerance significantly at the L5 level. Regarding the effectiveness of the DN upon spine kinematics, their derivatives were more sensitive.

INTERPRETATION

It appeared that the pathological type of torso movement was acutely affected by DN. NS-LBP patients showcased smoother movement immediately after the intervention and better control as imprinted in the higher derivative of motion although range of motion did not improve. This quantitative variable may not be subjected to acute effects of DN but rather need additional time and training to be improved.

A Pilot Study on Continuous Breaststroke Phase Recognition with Fast Training Based on Lower-Limb Inertial Signals

In this study, we proposed a continuous stroke phase recognition method with lower-limb inertial signals. The aim of the method was to decrease the time needed and to relieve the burdensome manual configurations in the tasks of human underwater motion recognition. The method automatically segmented the data of a period of time into stroke cycles and three sub-phases (propulsion, glide and recovery). K-nearest neighbor algorithm (k-NN) was used as the classifier to train the segmented data and classify the new data on each sample interval. To validate the proposed recognition method, three elite swimmers were recruited. We also designed an wearable sensing system for human underwater motion sensing with inertial measurement units (IMUs). With only data of 5 stroke cycles for training, the recognizer produced accurate recognition results. The average precision across the phases and the subjects was 93.7% and the average recall was 92.6%. We also investigated the time difference of the key stroke events (stroke phase transitions) between the recognized decisions and the reference ones. The average time difference was 66.2 ms, which accounted for the 4.2% of a single stroke phase. The results of the pilot study proved the feasibility of the new method for human aquatic locomotion assistance tasks. Future efforts will be paid in this new direction for more promising results.

Classification methods can identify external constrains in swimming

The purpose of the present study is to examine whether the use of fins is identifiable based on swimmers' technique and to find out technique-related features that depict fins' influence. First, a number of features were extracted from kinematic data given by movement sensors attached to swimmers' bodies during butterfly swimming technique. Then, dimensionality reduction, feature selection and classification methods were applied to the extracted features. Two classification tasks were defined, one for the three classes of long, short and no fins, attaining accuracy up to 70, 62 and 70%, respectively, and the two-class simplified version (long fins, no fins) with accuracy up to 78%. These high accuracy levels were also found statistically significant and suggest that the use of fins influences swimming technique in a recognizable way and that the selected features that depict those differences are swimming type depended.

High Rate of Return to Swimming After Hip Arthroscopy for Femoroacetabular Impingement

PURPOSE

To evaluate patients' ability to return to swimming after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) with capsular closure.

METHODS

Consecutive FAIS patients who had undergone hip arthroscopy for the treatment of FAIS by a single fellowship-trained surgeon were reviewed. The inclusion criteria included patients with a diagnosis of FAIS who self-reported being swimming athletes with a minimum clinical follow-up duration of 2 years. For all patients, we assessed demographic data; preoperative physical examination findings, imaging findings, and patient-reported outcome (PRO) scores including the modified Harris Hip Score, Hip Outcome Score-Activities of Daily Living subscale, Hip Outcome Score-Sports-Specific subscale, and visual analog scale for pain; and postoperative examination findings and PROs at a minimum of 2 years after surgery, including a swimming-specific questionnaire.

RESULTS

The study included 26 patients (62% female patients; average age, 31.3 ± 7.2 years; average body mass index, 24.2 ± 2.7 kg/m²). Preoperatively, 24 patients (92%) were unable to swim at their preinjury level, and swimming was either decreased or discontinued entirely at an average of 6.0 ± 4.0 months before surgery. All 26 patients (100%) returned to swimming at an average of 3.4 ± 1.7 months after surgery, including 14 (54%) who returned at a higher level of performance than their preoperative state, 10 (38%) who returned to the same level, and 2 (7%) who returned at a lower level. The ability to return at a higher level of performance was not associated with age (P = .81), sex (P = .62), or body mass index (P = .16). At an average of 31.2 ± 4.95 months' follow-up, postoperative PRO scores improved significantly from preoperative values (Hip Outcome Score-Activities of Daily Living subscale from 68.5 ± 19.9 to 93.9 ± 5.7, P < .0001; Hip Outcome Score-Sports-Specific subscale from 44.0 ± 21.0 to 85.2 ± 16, P < .0001; and modified Harris Hip Score from 59.5 ± 12.1 to 94 ± 8.6, P < .0001). The average patient satisfaction level was 93% ± 9%.

CONCLUSIONS

Recreational and amateur swimmers return to swimming 100% of the time after hip arthroscopy for FAIS, with just over half returning at a higher level, and most of these patients return within 4 months after surgery. This information is critical in counseling patients on their expectations with respect to returning to swimming after hip arthroscopy for FAIS.

LEVEL OF EVIDENCE

Level IV, case series.