Purpose: The application of Poincaré-plot analysis to heart-rate variability (HRV) is a common method for the assessment of autonomic balance. However, results obtained from the indexes provided by this analysis tend to be difficult to interpret. In this study the authors aimed to prove the usefulness of 2 new indexes: the stress score (SS) and the sympathetic:parasympathetic ratio (S:PS ratio).Methods: 25 professional Spanish soccer players from same team underwent 330 resting measurements of HRV. All subjects experienced 10 min of HRV monitoring through an R-R-interval recorder. The following parameters were calculated: (1) Poincaré-plot indexes: SD1 (transverse axis), which is proportional to parasympathetic activity; SD2 (longitudinal axis), which is inversely proportional to sympathetic activity; and the SD1:SD2 ratio; (2) time-domain parameters: standard deviation of R-R intervals (SDNN), root-mean-square differences of successive heartbeat intervals (rMSSD), and percentage of successive R-R-interval pairs differing in more than 50 ms in the entire recording divided by the total number of R-R intervals (pNN50); and (3) the proposed 2 new indexes: the SS and the S:PS ratio.Results: The study found a high negative correlation between the SS and SDNN (R² = .94). The S:PS ratio correlated inversely to rMSSD (R² = .95), SDNN (R² = .94), and pNN50 (R² = .74). The S:PS ratio showed a strong correlation with SD1 (R² = .95) and SS (r = .87, R² = .88).Conclusions: The application of the SS as sympathetic-activity index and the S:PS ratio as a representation of autonomic balance (SS:SD1) provides a better understanding of the Poincaré-plot method in HRV.

Objective: To analyse HRV at rest in healthy people and in patients with acute myocardial infarction (AMI) and how it changes during aerobic exercise. Methods: The heartbeat signal was recorded beat to beat for 15 minutes at rest and 15 minutes while pedalling in 10 healthy and active men (H group) and 10 cardiac patients (C group). The statistical parameters in the time domain were calculated as well as the spectral analysis applying the Fast Fourier Transform (FFT) and Poincare’s graphic analysis (PGA). Results: At rest, H group have an average SDRR (standard deviation of RR intervals) of 71.24 msec, a pRR50 (percentage of differences higher than 50 msec in RR intervals) of 9.97% and a PGA called “comet-type”. The C group have a SDRR of 36.69 msec, a pRR50 of 1.69%, and a PGA “torpedo-type”. These data show a low or moderate risk for healthy people and a high risk for patients. The FFT analysis lies in the very-low-frequency (VLF) zone in both groups. During exercise, H group shows a significant decrease in all parameters; the PGA turns to “torpedo-type” and the FFT remains in the VLF zone. However, C group is characterised by the maintenance of pRR50, no change in PGA and a second peak in FFT in the high-frequency zone. Conclusion: The HRV at rest and during aerobic exercise follows a different pattern in healthy people and in patients and it provides further information about performance during exercise.

Heart rate variability (HRV) can provide useful information on physiological adaptations to training, but its role is unknown in professional soccer. The aim of this study was to determine an HRV profile in professional soccer over a season. A total of 504 records were made of the heart beat signal throughout a season from 22 professional soccer players. HRV was recorded in a sitting position, early morning and fasting for a period of 10 min. Standard deviation 1 and 2 (SD1, SD2), standard deviation of normal to normal R-R intervals (SDNN), Root Mean Square of the Successive Differences (rMSSD), percentage of RR intervals > 50 ms (pNN50), Sample Entropy (SampEn), Stress Score (SS) and sympathetic/parasympathetic ratio (S/PS ratio) were calculated. SDNN, rMSSD, pNN50, SD1 and SD2 showed an identical behaviour throughout the season, with lower values in the pre-season and the end of the season. SS and S/PS ratio indicated a sympathetic stress alert in the same periods. A weekly recording of the HRV over a 10 min period that includes a Poincaré plot with SS and S/PS ratio and at least one variable of the time domain is a useful tool for the follow-up of the individual assimilation of weekly workloads, including the game.

Damage to intramuscular tendons is very common in sports injuries, specifically in soleus muscle injuries. This study sought to compare the effects of applying ultrasound‐ (US‐) guided percutaneous needle electrolysis (PNE) in combination with an eccentric exercise program on pain and functionality in dancers with chronic soleus injury, located in the central tendon. Thirty dancers with injured central tendon of the soleus muscle were randomly allocated to a PNE group (n = 10), an eccentric exercise group (n = 10), or a combined group (n = 10). Pain, ankle dorsiflexion range of motion (DROM), endurance, the heel raise test, the DFOS questionnaire, and the minimal clinically important difference (MCID) were analyzed at baseline and after treatment (four weeks). Over half (52%) of the dancers had a chronic soleus muscle injury. Variables for pain, DROM, the heel rise test, ADL, technique, DFOS total, and DFOS‐subjective variables showed significant differences (P < 0.05) in pretreatment and posttreatment in all groups, whereas no significant differences were observed between intervention groups. However, the combined group showed a higher percentage of changes compared to the other groups, and these dancers had greater perceived changes (MCID = 4.70 ± 1.42). The conclusion of the study was that dancers with chronic soleus injury, located in the central tendon, treated with a combination of US‐guided PNE and an eccentric exercise program displayed improved outcomes compared to the application of PNE therapy or eccentric exercise alone. The US‐guided PNE, combined with an eccentric exercise program, is a useful therapeutic tool for the treatment of chronic soleus injury, located in the central tendon. The trial is registered with NCT04042012.

Background Ultrasound (US)-guided percutaneous needle electrolysis (PNE) is a novel minimally invasive approach, which involves the application of a galvanic current via an acupuncture needle. As in any procedure involving needling, vagal reactions have been reported during PNE. Objective To examine for changes in autonomic activity during the US-guided PNE technique on healthy patellar tendons by measurement and analysis of heart rate variability (HRV). Methods Twenty-two male footballers were randomly allocated to: a control group (11 players), for whom HRV was recorded for 10 min, both at rest and during an exhaustive US examination of the patellar tendon and adjacent structures; and an experimental group (11 players), for whom HRV was recorded for 10 min, both at rest and during application of US-guided PNE on the patellar tendon. The following HRV parameters were assessed: mean NN interval, mean heart rate, time domain parameters (SDNN, rMSSD, pNN50), diameters of the Poincaré plot (SD1, SD2), stress score, and sympathetic/parasympathetic ratio. Results There were no differences between groups in any baseline measurements, nor were there any significant differences between control group measurements (baseline vs intervention). The experimental group exhibited statistically significant increases in SDNN/SD1 (p=0.02/p=0.03) and SD2 (p=0.03), indicating increased parasympathetic and decreased sympathetic activity, respectively. Conclusions US-guided PNE was associated with an autonomic imbalance characterised by greater parasympathetic activity, which could potentially result in a vasovagal reaction. Care should be taken to monitor for adverse reactions during US-guided PNE and simple HRV indicators may have a role in early detection.