Repeated Measures Correlation Research Articles

Active matrix metalloproteinase-8 and interleukin-6 detect periodontal degeneration caused by radiotherapy of head and neck cancer: a pilot study

ABSTRACT Background: This cohort study investigated the role of the active matrix metalloproteinase-8 (aMMP-8) and interleukin-6 (IL-6) as oral fluid biomarkers for monitoring the periodontal degeneration occurring in head and neck cancer (HNC) patients treated by radiotherapy. Research design and methods: Eleven patients, aged 28–74, diagnosed with HNC were included in the study. Complete periodontal and oral examinations were performed pre-radiotherapy and 1 month after radiotherapy. Mouthrinse samples (pre-radiotherapy, after 6 weeks of radiotherapy and 1 month after radiotherapy) were assayed by aMMP-8 point-of-care-kit (PerioSafe®/ORALyzer®) for aMMP-8 and ELISA for IL-6. Results: HNC radiotherapy had a deteriorating impact on the periodontium and a significant impact on periodontal biomarkers aMMP-8 and IL-6 and increased their levels in mouthrinse. Clinical-attachment-loss (CAL) (site of greatest loss: mean = 1.7 mm, range = 1–3 mm) corresponding to rapid progression of periodontitis. There was a positive repeated measures correlation (rmcorr = 0.667) between the aMMP-8 and IL-6 levels. Conclusions: Elevated aMMP-8 levels were observed 1 month after radiotherapy among some HNC patients suggesting a prolonged increased susceptibility to further periodontal tissue destruction. Currently available aMMP-8 point-of-care testing could be useful to monitor and assess quantitatively online and real-time the risk of deterioration of periodontal health during HNC radiotherapy.

Use of Numerically Blinded Ratings of Perceived Exertion in Soccer: Assessing Concurrent and Construct Validity.

To examine the concurrent and construct validity of numerically blinded ratings of perceived exertion (RPEs). A total of 30 elite male youth soccer players (age 16.7 [0.5]y) were monitored during training and matches over a 17-wk in-season period. The players' external loads were determined via raw 10-Hz global positioning system. Heart rate (HR) was collected continuously and expressed as Bannister and Edwards training impulses, and minutes >80% of the players predetermined the maximum HR by the Yo-Yo Intermittent Recovery Test Level 1. RPE was collected confidentially 10 to 15min after training/matches using 2 methods: (1)a traditional verbal response to the 0 to 100 category-ratio "centiMax" scale (RPE) and (2)numerically blinded RPE centiMax scale (RPEblind) with the response selected manually via a 5 × 7-in tablet "slider." The RPE and RPEblind were divided by 10 and multiplied by the duration to derive the sessional RPE. Linear mixed models compared ratings, and within-subject repeated-measures correlations assessed the sessional RPE versus HR and external load associations. There were no differences between the RPE and RPEblind (0.19; 95% confidence intervals, -0.59 to 0.20 au, P = .326) or their session values (13.5; 95% confidence intervals, -17.0 to 44.0 au, P = .386), and the ratings were nearly perfectly correlated (r = .96). The associations between the sessional RPE versus HR and external load metrics were large to very large (r = .65-.81), with no differences between the RPE methods (P ≥ .50). The RPEblind also reduced verbal anchor clustering and integer bias by 11% and 50%, respectively. RPEblind demonstrated concurrent and construct validity versus the traditional method, and may be used in situations where practitioners have concerns regarding the authenticity of athlete ratings.

The Concurrent Validity of Session-Rating of Perceived Exertion Workload Obtained Face-to-Face Versus Via an Online Application: A Team Case Study.

To compare the concurrent validity of session-rating of perceived exertion (sRPE) workload determined face-to-face and via an online application in basketball players. Sixteen semiprofessional, male basketball players (21.8 [4.3]y, 191.2 [9.2]cm, 85.0 [15.7]kg) were monitored during all training sessions across the 2018 (8 players) and 2019 (11 players) seasons in a state-level Australian league. Workload was reported as accumulated PlayerLoad (PL), summated-heart-rate-zones (SHRZ) workload, and sRPE. During the 2018 season, rating of perceived exertion (RPE) was determined following each session via individualized face-to-face reporting. During the 2019 season, RPE was obtained following each session via a phone-based, online application. Repeated-measures correlations with 95% confidence intervals were used to determine the relationships between sRPE collected using each method and other workload measures (PL and SHRZ) as indicators of concurrent validity. Although all correlations were significant (P < .05), sRPE obtained using face-to-face reporting demonstrated stronger relationships with PL (r = .69 [.07], large) and SHRZ (r = .74 [.06], very large) compared with the online application (r = .29 [.25], small [PL] and r = .34 [.22], moderate [SHRZ]). Concurrent validity of sRPE workload was stronger when players reported RPE in an individualized, face-to-face manner compared with using a phone-based online application. Given the weaker relationships with other workload measures, basketball practitioners should be cautious when using player training workloads predicated on RPE obtained via online applications.

Sensor-based indicators of performance changes between sessions during robotic surgery training

Training of surgeons is essential for safe and effective use of robotic surgery, yet current assessment tools for learning progression are limited. The objective of this study was to measure changes in trainees’ cognitive and behavioral states as they progressed in a robotic surgeon training curriculum at a medical institution. Seven surgical trainees in urology who had no formal robotic training experience participated in the simulation curriculum. They performed 12 robotic skills exercises with varying levels of difficulty repetitively in separate sessions. EEG (electroencephalogram) activity and eye movements were measured throughout to calculate three metrics: engagement index (indicator of task engagement), pupil diameter (indicator of mental workload) and gaze entropy (indicator of randomness in gaze pattern). Performance scores (completion of task goals) and mental workload ratings (NASA-Task Load Index) were collected after each exercise. Changes in performance scores between training sessions were calculated. Analysis of variance, repeated measures correlation, and machine learning classification were used to diagnose how cognitive and behavioral states associate with performance increases or decreases between sessions. The changes in performance were correlated with changes in engagement index (rrm=−.25,p<.001) and gaze entropy (rrm=−.37,p<.001). Changes in cognitive and behavioral states were able to predict training outcomes with 72.5% accuracy. Findings suggest that cognitive and behavioral metrics correlate with changes in performance between sessions. These measures can complement current feedback tools used by medical educators and learners for skills assessment in robotic surgery training.

Evaluation of the effects of intraabdominal hypertension on equine central venous pressure.

To evaluate the effect of changes in intraabdominal pressure (IAP) on central venous pressure (CVP) in normal horses. Experimental, in vivo study. University Teaching Hospital. Convenience sample of 7 mixed breed horses-5 geldings and 2 mares. Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20mm Hg over 30 minutes, and maintained at that pressure for 30 minutes to evaluate the effect of sustained intraabdominal hypertension. CVP was obtained from the cranial vena cava, concurrent with pressure obtained from the peritoneal cavity. CVP increased as IAP increased up to 12mm Hg, and declined as IAP increased further. The changes in CVP over time were significantly different (P< 0.03). Repeated measures correlation was positive, and highest, for mean CVP as IAP increased from 0 to 12mm Hg (r=.70; 95% CI, .43-.85; P< 0.0001). Correlation of mean CVP with insufflation pressure became negative as IAP increased further from 15 to 20mm Hg (r=-.47; 95% CI, -.66 to -.21; P= 0.0006). This report provides preliminary data demonstrating a biphasic trend in equine CVP caused by changes in IAP, similar to that observed in other species. Further investigations are needed to evaluate this trend and to confirm these results in clinical patients.

Changes in \u03b3H2AX and H4K16ac levels are involved in the biochemical response to a competitive soccer match in adolescent players

The aim of this study was to examine novel putative markers of the response to the competitive soccer match in adolescent players, such as changes in global levels of γH2AX and H4K16ac in the chromatin of peripheral mononuclear blood cells (PMBCs) and a Fourier-transform infrared spectroscopy (FTIR)-based biochemical fingerprint of serum. These characteristics were examined with reference to the physiological and metabolic aspects of this response. Immediately post-match we noticed: (1) a systemic inflammatory response, manifesting as peaks in leukocyte count and changes in concentrations of IL-6, TNFα, and cortisol; (2) a peak in plasma lactate; (3) onset of oxidative stress, manifesting as a decline in GSH/GSSG; (4) onset of muscle injury, reflected in an increase in CK activity. Twenty-four hours post-match the decrease in GSH/GSSG was accompanied by accumulation of MDA and 8-OHdG, macromolecule oxidation end-products, and an increase in CK activity. No changes in SOD1 or GPX1 levels were found. Repeated measures correlation revealed several associations between the investigated biomarkers. The FTIR analysis revealed that the match had the greatest impact on serum lipid profile immediately post-game. In turn, increases in γH2AX and H4K16ac levels at 24 h post-match indicated activation of a DNA repair pathway.

Associations Between Heart Rate Variability-Derived Indexes and Training Load: Repeated Measures Correlation Approach Contribution.

Davletyarova, K, Vacher, P, Nicolas, M, Kapilevich, LV, and Mourot, L. Associations between heart rate variability-derived indexes and training load: repeated measures correlation approach contribution. J Strength Cond Res 36(7): 2005-2010, 2022-This study aimed to evaluate whether similar associations between indexes derived from heart rate variability (HRV) analyses and training load (TL) could be obtained by using the commonly used Pearson correlation technique and the repeated measures correlation (rmcorr). Fourteen well-trained swimmers (18.5 ± 1.6 years) participated. The training period lasted 4 weeks with a gradual increase in TL. Daily external TL (exTL) and internal TL (inTL) were summed to obtain a weekly TL, and HRV analyses were performed every Saturday morning. During the 4-week period, exTL and inTL increased (p < 0.05) together with a decrease (p < 0.05) in heart rate and an increase (p < 0.05) of cardiac parasympathetic indexes. No significant correlation was found using Pearson correlation while significant associations were found using rmcorr; considering exTL, positive (mean R-R interval [MeanRR], root mean square of differences between successive RR interval [RMSSD], low frequency [LF], high frequency [HF], instantaneous beat-to-beat variability [SD1], continuous beat-to-beat variability [SD2], SD1/SD2; r from 0.59 to 0.46, p value from <0.001 to 0.002) and negative (mean heart rate [meanHR]; r = -0.55, p < 0.001) associations were found. Considering inTL, positive (MeanRR, RMSSD, LF, HF, HFnu, SD1, SD2, SD1/SD2; r from 0.56 to 0.34, p-value from <0.001 to 0.025) and negative (meanHR, LFnu, LF/HF; r from -0.49 to -0.34, p value from 0.001 to 0.025) associations were found. The rmcorr statistical method was able to show associations between parasympathetic indexes and TL contrary to Pearson correlation analysis. Because rmcorr is specifically designed to investigate within-individual association for paired measures assessed on 2 or more occasions for multiple individuals, it should constitute a tool for future training monitoring researches based on a repeated-measures protocol.

The Relationships Between External and Internal Workloads During Basketball Training and Games.

To investigate the relationships between external and internal workloads using a comprehensive selection of variables during basketball training and games. Eight semiprofessional, male basketball players were monitored during training and games for an entire season. External workload was determined as PlayerLoad™: total and high-intensity accelerations, decelerations, changes of direction, and jumpsand total low-intensity, medium-intensity, high-intensity, and overall inertial movement analysis events. Internal workload was determined using the summated-heart-rate zones and session rating of perceived exertion models. The relationships between external and internal workload variables were separately calculated for training and games using repeated-measures correlations with 95% confidence intervals. PlayerLoadwas more strongly related to summated-heart-rate zones (r = .88 ± .03, very large [training]; r = .69 ± .09, large [games]) and session rating of perceived exertion (r = .74 ± .06, very large [training]; r = .53 ± .12, large [games]) than other external workload variables (P < .05). Correlations between total and high-intensity accelerations, decelerations, changes of direction, and jumps and total low-intensity, medium-intensity, high-intensity, and overall inertial movement analysis events and internal workloads were stronger during training (r = .44-.88) than during games (r = .15-.69). PlayerLoadand summated-heart-rate zones possess the strongest dose-response relationship among a comprehensive selection of external and internal workload variables in basketball, particularly during training sessions compared with games. Basketball practitioners may therefore be able to best anticipate player responses when prescribing training drills using these variables for optimal workload management across the season.

Longitudinal proneuroactive and neuroactive steroid profiles in medication-free women with, without and at-risk for perinatal depression: A liquid chromatography-tandem mass spectrometry analysis

BackgroundNeuroactive steroids (NAS) are derivatives of cholesterol or steroidal precursors made in the gonads, adrenal gland, placenta and brain. We characterized longitudinal plasma proneuroactive and NAS in healthy perinatal comparison women (HPCW), women at-risk for perinatal depression (AR-PND), and women with PND with/without comorbid anxiety. We hypothesized that AR-PND women who either did or did not go on to develop PND would have elevated NAS concentrations as compared to HPCW and that NAS would be correlated to depressive and anxiety symptoms. MethodsA prospective cohort study evaluated 75 medication-free perinatal women (HPCW, n = 30; AR-PND, n = 19; PND, n = 26). Standardized depression and anxiety assessments and blood samples were completed across 5 visits. Structured Clinical Interviews for DSM-IV TR Disorders were administered at study entry and exit. Plasma pregnenolone, progesterone, 5α- and 5β-dihydroprogesterone, pregnanolone, allopregnanolone, deoxycorticosterone and tetrahydrodeoxycorticosterone were quantified by liquid chromatography-tandem mass spectrometry. Longitudinal relationships between risk-group, depression and anxiety symptoms, and NAS concentrations were analyzed using generalized estimating equations to control for repeated measures correlations. ResultsPerinatal 5α-dihydroprogesterone, 5β-dihydroprogesterone, allopregnanolone, deoxycorticosterone, and tetrahydrodeoxycorticosterone concentrations were higher in AR-PND and PND women compared to HPCW (β = 3.57 ± 1.40 and β = 2.11 ± 1.12, p = 0.03; β = 0.18 ± 0.06 and β = 0.03 ± 0.05, p = 0.02; β = 1.06 ± 0.42 and β = 1.19 ± 0.47, p = 0.01; β = 0.17 ± 0.07 and β = 0.11 ± 0.06, p = 0.05; β = 0.03 ± 0.01 and β = 0.03 ± 0.01, p = 0.05, respectively). Perinatal allopregnanolone, 5α-dihydroprogesterone and tetrahydrodeoxycorticosterone were positively associated with HAM-D17 (all p < 0.02). HAM-A was positively associated with 5α- and 5β-dihydroprogesterone, pregnanolone, allopregnanolone, deoxycorticosterone and tetrahydrodeoxycorticosterone (all p < 0.05). A history of depression was associated with increased 5α-dihydroprogesterone (2.20 ± 1.09, p = 0.05), deoxycorticosterone (0.13 ± 0.06, p = 0.03) and tetrahydrodeoxycorticosterone (0.03 ± 0.01, p = 0.02). ConclusionTo our knowledge, this study represents the largest prospective study of 5-α and 5-β reductase products of progesterone and deoxycorticosterone in HPCW and women AR-PND. Data suggest that PND is associated with both a reduction of progesterone to 5β-dihydroprogesterone, 5α-dihydroprogesterone, and allopregnanolone, and the 21-hydroxylation to deoxycorticosterone and tetrahydrodeoxycorticosterone. The shift towards 5α-dihydroprogesterone, deoxycorticosterone and tetrahydrodeoxycorticosterone was associated with a history of depression, a significant risk factor for PND.

Volume of hippocampal subregions and clinical improvement following electroconvulsive therapy in patients with depression

It is thought that the hippocampal neurogenesis is an important mediator of the antidepressant effect of electroconvulsive therapy (ECT). However, most previous studies failed to demonstrate the relationship between the increase in the hippocampal volume and the antidepressant effect. We reinvestigated this relationship by looking at distinct hippocampal subregions and applying repeated measures correlation. Using a 3 Tesla MRI-scanner, we scanned 22 severely depressed in-patients at three time points: before the ECT series, after the series, and at six-month follow-up. The depression severity was assessed by the 17-item Hamilton Rating Scale for Depression (HAMD-17). The hippocampus was segmented into subregions using Freesurfer software. The dentate gyrus (DG) was the primary region of interest (ROI), due to the role of this region in neurogenesis. The other major hippocampal subregions were the secondary ROIs (n = 20). The general linear mixed model and the repeated measures correlation were used for statistical analyses. Immediately after the ECT series, a significant volume increase was present in the right DG (Cohen's d = 1.7) and the left DG (Cohen's d = 1.5), as well as 15 out of 20 secondary ROIs. The clinical improvement, i.e., the decrease in HAMD-17 score, was correlated to the increase in the right DG volume (rrm = −0.77, df = 20, p < .001), and the left DG volume (rrm = −0.75, df = 20, p < .001). Similar correlations were observed in 14 out of 20 secondary ROIs. Thus, ECT induces an increase not only in the volume of the DG, but also in the volume of other major hippocampal subregions. The volumetric increases may reflect a neurobiological process that may be related to the ECT's antidepressant effect. Further investigation of the relationship between hippocampal subregions and the antidepressant effect is warranted. A statistical approach taking the repeated measurements into account should be preferred in the analyses.

Measured Versus Heart Rate-Derived Core Temperature During Outdoor Work In The Southeastern United States

Climate change is increasing the number of hot days to which outdoor workers are exposed, thereby increasing their risk of heat illness. Currently, continuous monitoring of core temperature (Tc) is expensive, invasive, and impractical. The BioModule is a non-invasive physiological monitor that uses heart rate to provide an estimation of Tc, but its accuracy is unknown. PURPOSE: To test the association between measured gastrointestinal temperature (TGI) and estimated core temperature (Tc-est) from the BioModule device during outdoor work in a hot environment. METHODS: Twenty groundskeepers (18 men; mean±SD age = 38±8 y, body mass index = 31.5±7.5 kg/m2) swallowed an ingestible temperature sensor and strapped on a BioModule before work. TGI was collected every 15 minutes during the workday; Tc-est was determined by a 1-min average from the same time of day. Data collection occurred in Alabama during July and August (31.4±3.1 °C WBGT). Relationship between TGI and Tc-est was quantified using the repeated measures correlation coefficient (rrm). Agreement (bias±1.96 SD) between TGI and Tc-est was evaluated using the Bland-Altman method for repeated observations. RESULTS: There was a moderate, positive relationship between TGI and Tc-est (rrm = 0.56, p < 0.001). Agreement analysis indicated that Tc-est overestimated TGI (0.28±0.58 °C). The error between Tc-est and TGI was larger at lower temperatures, as indicated by a strong negative trend (Pearson’s r = −0.73). CONCLUSION: The BioModule provides an estimation of Tc that may be helpful as a guide during outdoor work in hot environments but should not be used for safety considerations or measurement of Tc . Funded by the Deep South Center for Occupational Safety and Health, a National Institute for Occupational Safety and Health Education and Research Center.

Validation Of Flow-mediated Slowing As A Measure Of Endothelial Function

BACKGROUND: Flow-Mediated Slowing (FMS) is a potentially simple, automated and user-objective test for assessing endothelial function. FMS can be defined as the minimum pulse wave velocity (PWVmin) during reactive hyperemia. PURPOSE: The purpose of this study was to determine the effects of acute endothelial dysfunction on PWVmin. It was hypothesized that endothelial dysfunction would increase PWVmin. METHODS: 22 young, healthy adults (23.8 yrs ± 4.1, 73% F, 22.8 kg/m2 ± 2.8) underwent simultaneous assessment of Flow-Mediated Dilation (FMD) and PWVmin at baseline and immediately following 30min of an endothelial dysfunction protocol. FMD is the current gold-standard test of endothelial function and was used to confirm endothelial dysfunction. Endothelial dysfunction was induced by increasing retrograde shear stress in the brachial artery via inflation of a pneumatic tourniquet to 75 mm Hg around the forearm. PWV was measured from the upper-arm to the wrist using an oscillometric-based device, and brachial FMD was measured using duplex Doppler ultrasound. FMD (%) was calculated as the mean increase in diameter during reactive hyperemia, and PWVmin as the minimum pulse wave velocity during reactive hyperemia. Linear mixed models were used to assess baseline versus endothelial dysfunction changes in PWVmin and FMD, controlling for within-subject changes in mean arterial pressure. Inter-individual associations between baseline PWVmin and FMD were examined using Pearson’s product moment correlation, and intra-individual associations between change (baseline vs. endothelial dysfunction) in PWV and change in FMD using the repeated measures correlation package for R. RESULTS: The endothelial dysfunction protocol resulted in large effect size (ES) decrease in FMD (∆ = -3.10, 95%CI: -4.15, -2.05, ES = -1.3), and a moderate significant increase in PWVmin (∆ = 0.16, 95%CI: 0.05, 0.28, ES = 0.6). There was a moderate inter-individual association between FMD and PWVmin (r = 0.46), and a large intra-individual association between FMD and PWVmin (r = -0.61). CONCLUSIONS: Acute changes in PWVmin may be a user-objective, automated, and viable tool for monitoring acute changes in endothelial function.

Changes in perceptions of mental fatigue during a season in professional under-23 English Premier League soccer players

ABSTRACT The present study assessed changes in academy soccer players’ perception of mental fatigue (MF) across a competitive season, investigating the relationship between MF and other subjective measures of wellness. Ten players completed a modified Brief Assessment of Mood (BAM+) questionnaire that included the question: “How mentally fatigued do you feel”? on match-day (MD) and one (MD+1), two (MD+2) and three (MD+3) days post-match (35 matches). Players reported their MF, along with other subjective measures (sleep, muscle soreness, fatigue and motivation). Results found MF was elevated on MD+1 (43±1 mm) compared to all other days (all P≤0.001). Players reported lower MF on MD+1 in the late-season phase (34±2 mm) compared to both early- (50±2 mm, P≤0.001) and mid-season (46±2 mm, P≤0.001). This coincided with an 80%-win rate in the late-season phase versus the early- (33%) and mid-season (50%). There were very strong repeated-measures correlations between changes in MF and sleep (r=−0.77), muscle soreness (r=0.94), fatigue (r=0.92) and motivation (r=−0.89; all P ≤ 0.0005). In conclusion, MF was closely aligned to match success and other wellness variables. This data suggests a potential lack of sensitivity for identifying MF using a subjective questionnaire. Therefore, researchers and practitioners could work together to identify other ways of practically assessing MF.

Sound localization latency in normal hearing and simulated unilateral hearing loss

Directing gaze towards auditory events is a natural behavior. In addition to the well-known accuracy of auditory elicited gaze responses for normal binaural listening, their latency is a measure of possible clinical interest and methodological importance. The aim was to develop a clinically feasible method to assess sound localization latency (SLL), and to study SLL as a function of simulated unilateral hearing loss (SUHL) and the relationship with accuracy. Eight healthy and normal-hearing adults (18–40 years) participated in this study. Horizontal gaze responses, recorded by non-invasive corneal reflection eye-tracking, were obtained during azimuthal shifts (24 trials) of a 3-min continuous auditory stimulus. In each trial, a sigmoid function was fitted to gaze samples. Latency was estimated by the abscissa corresponding to 50% of the arctangent amplitude. SLL was defined as the mean latency across trials. SLL was measured in normal-hearing and simulated SUHL conditions (SUHL30 and SUHL43: mean threshold of 30 dB HL and 43 dB HL across 0.5, 1, 2, and 4 kHz). In the normal-hearing condition, the mean ± SD SLL was 280 ± 40 ms (n = 8) with a test-retest SD = 20 ms. A linear mixed model showed a statistically significant effect of listening condition on SLL. The SUHL30 and SUHL43 conditions revealed a mean SLL of 370 ± 49 ms and 540 ± 120 ms, respectively. Repeated measures correlation analysis showed a clear relationship between SLL and the average sound localization accuracy (R2 = 0.94). The rapid and reliable method to obtain SLL may be an important clinical tool for evaluation of binaural processing. Future studies in clinical cohorts are needed to assess whether SLL may reveal information about binaural processing abilities beyond that afforded by sound localization accuracy.

Profiles of Heart Rate Variability and Bar Velocity after Resistance Exercise.

The aim of this investigation was to observe the association in the time course in recovery between multiple heart rate variability (HRV) metrics and neuromuscular performance, as assessed by mean bar velocity (BVM) in the back squat, over a 72-h period after an exhaustive back squat protocol. Eight resistance-trained males completed five laboratory visits within a 7-d period. The first visit involved short-term HRV recordings followed by a familiarization of BVM procedures and a one-repetition maximum test of the back squat. Forty-eight hours later, participants returned to the laboratory for prestimulus measurements, immediately followed by a back squat protocol (8 sets of 10 repetitions at 70% of one-repetition maximum with a 2-min rest). The HRV and the BVM measurements were replicated at 0.5, 24, 48, and 72 h after squat protocol. A multivariate profile analysis and repeated-measures correlation between recovery scores [(new/prestimulus) × 100] for each HRV metric and BVM was computed. All log-transformed (ln) HRV metrics, except low frequency (lnLF) (P = 0.051), had a significant interaction with BVM over time (P < 0.05), indicating that recovery scores in BVM and HRV were not parallel. In addition, recovery scores in all HRV metrics significantly differed from BVM (P < 0.05) in at least one time point across the 72-h period. Furthermore, repeated-measures correlation analysis indicated a lack of intraindividual association (P > 0.05) between the change in BVM and all HRV measurements over time. The time course in recovery in HRV measurements after an exhaustive bout of lower-body resistance exercise was not associated with neuromuscular performance recovery.

Characteristics, Properties, and Associations of Self-Assessed Pain Questionnaires: A Literature Review and Prospective Cohort Study Among Dance Students

To provide an overview of measurement properties of the Oslo Sports Trauma Research Center Questionnaire (OSTRCQ), pain visual analogue scale (VAS-pain) and Self-Estimated Functional Inability Because of Pain (SEFIP) scale in dance populations, and to investigate the relationship between these questionnaires in pre-professional contemporary dancers. A search of PubMed was conducted and studies were included if they 1) used one of the three questionnaires within a dance population and 2) assessed the reliability, validity, or responsiveness of the questionnaire(s). 134 dance students (67.5% female; 19.4±1.5 yrs) were prospectively followed during 1 academic year. The OSTRCQ, VAS-pain, SEFIP, and injuries were self-assessed on a monthly basis. Pearson correlation analyses and repeated measures correlation analyses were performed to identify possible associations. The literature overview resulted in two studies describing measurement properties of the SEFIP (n=1) and OSTRCQ (n=1). Prevalence of injuries ranged from 23.1 to 42.6%. Weak monthly correlations (r=0.14-0.50) were found between OSTRCQ and SEFIP. Moderate monthly correlations (r=0.54-0.71) were found between OSTRCQ and VAS-pain, and weak/moderate monthly correlations (r=0.30-0.62) were found between SEFIP and VAS-pain. Repeated measures correlation demonstrated a moderate overall correlation between ORSTCQ and VAS-pain (r=0.57), with weak overall correlations between ORSTCQ and SEFIP (r=0.26) and SEFIP and VAS-pain (r=0.34). Studies on measurement properties of questionnaires in dance are scarce. Weak/moderate associations were found between the OSTRCQ, SEFIP, and the VAS-pain questionnaires. Future high-quality research should investigate measurement properties of these questionnaires within dance populations. The results contribute by substantiating choices when developing a surveillance system.

The Validity of the Session Rating of Perceived Exertion Method for Measuring Internal Training Load in Professional Classical Ballet Dancers.

The aim of this study was to investigate the convergent validity of session rating of perceived exertion (s-RPE) with objective measures of internal training load (TL) in professional classical ballet dancers. Heart rate and s-RPE data were collected in 22 professional classical ballet dancers across a total of 218 ballet class or rehearsal sessions. Eleven participants completed at least 9 sessions, and were therefore included in analyses of individual relationships between s-RPE and objective measures. To calculate s-RPE, the session duration was multiplied by the RPE, measured using the modified Borg CR-10 scale. The Edwards summated heart rate zones (Edwards TRIMP) and Banister training impulse (Banister TRIMP) methods were used as criterion measures of internal TL. Pearson product-moment correlation coefficients were used to determine intra-individual relationships between s-RPE and objective measures. Repeated measures correlations were used to identify intra-individual relationships common across the cohort. Positive linear relationships were seen between s-RPE and objective measures across all session types [Edwards TRIMP: rrm (195) = 0.81, p < 0.001; Banister TRIMP: rrm (195) = 0.79, p < 0.001], in ballet class [Edwards TRIMP: rrm (58) = 0.64, p < 0.001; Banister TRIMP: rrm (58) = 0.59, p < 0.001], and in rehearsals [Edwards TRIMP: rrm (119) = 0.82, p < 0.001; Banister TRIMP: rrm (119) = 0.80, p < 0.001], as well as across both males [Edwards TRIMP: rrm (136) = 0.82, p < 0.001; Banister TRIMP: rrm (136) = 0.80, p < 0.001], and females [Edwards TRIMP: rrm (57) = 0.80, p < 0.001; Banister TRIMP: rrm (57) = 0.78, p < 0.001]. Intra-individual correlation coefficients ranged from 0.46–0.96 [Edwards TRIMP: mean r = 0.81 ± 0.11, p = 0.051 – < 0.001; Banister TRIMP: mean r = 0.78 ± 0.14, p = 0.13– < 0.001]. These results demonstrate that s-RPE is a valid and practical method for measuring internal TL in professional classical ballet dancers.

SUN-LB67 Revisit Serum Calcium Correction

Context: The serum calcium level is one of most routinely ordered tests in clinical practice. Many factors can affect calcium level and its interpretation. There are challenges and barriers in applying calcium correction formulas to every-day practice. Objective: Revisit correlation between total and ionized calcium levels, and dependence of serum calcium on albumin, pH and creatinine levels. Methods: This study included 1537 subjects enrolled in a parathyroid disease clinical protocol. We examined calcium and relevant biochemistry tests collected simultaneously and repetitively over consecutive years. Histograms, repeated measures correlation, correlation plots, and liner regression plots were used to analyze and visualize the data. Results: We found that: 1) directly measured total serum calcium and ionized calcium had excellent correlation and dependence with p-value=2.2e-16, repeated measures correlation coefficient (rmcorr)=0.919, and 95% interval (CI) = 0.916 to 0.922; 2) there was a low dependence between total serum calcium and albumin levels (rmcorr=0.454, 95% CI=0.433 to 0.474), a low dependence between ionized calcium and pH levels (rmcorr=-0.309, 95% CI= -0.326 to -0.292), and no dependence between total calcium and creatinine levels (rmcorr=0.026 95% CI=0.012 to 0.040); 3) using the commonly applied correction formulas, to either adjust total calcium based on albumin levels or else adjust ionized calcium based on pH levels, did not improve dependence among them. Conclusions: We therefore suggest using directly measured total serum calcium and/or ionized calcium level to assess clinical calcium status in general patients tested for parathyroid related disorders.

Is there an association between changes in pain or function with changes in scapular dyskinesis: A prospective cohort study

ObjectiveTo assess the association between changes in pain or function with changes in scapular dyskinesis in participants with subacromial shoulder pain. MethodForty-four participants with subacromial shoulder pain were assessed at baseline and 8 weeks later. The outcome measures included ‘pain at rest’ and ‘pain during movement’ using Numeric Pain Rating Scale (NPRS), shoulder function using Patient Specific Functional Scale (PSFS), and observation of scapular movement pattern using the scapular dyskinesis test. Robust paired t-tests were used to compare scores between baseline and follow-up. Repeated measures correlation coefficient was used to assess the association between changes in pain or function with changes in scapular dyskinesis scores. ResultsA fair association was found between improvement in function and improvement in scapular dyskinesis (correlation coefficient = −0.4, 95% CI: −0.6 to −0.1). No associations were found between changes in ‘pain at rest’ (correlation coefficient = −0.1, 95% CI: −0.2 to 0.2) or ‘pain during movement’ (correlation coefficient = 0.28, 95% CI: 0.0 to 0.5) with changes in scapular dyskinesis. ConclusionOur findings showed improvement in function is associated with improvement in scapular dyskinesis scores. Future studies should explore whether there is causal effect between improvement in scapular dyskinesis and function.

Diffusion tensor imaging of the anterior cruciate ligament following primary repair with internal bracing: A longitudinal study.

Diffusion tensor imaging (DTI) provides information about tissue microstructure and its degree of organization by quantifying water diffusion. We aimed to monitor longitudinal changes in DTI parameters (fractional isotropy, FA; mean diffusivity, MD; axial diffusivity, AD; radial diffusivity, RD) of the anterior cruciate ligament (ACL) following primary repair with internal bracing (IBLA). Fourteen patients undergoing IBLA were enrolled prospectively and scheduled for clinical follow-up, including instrumented laxity testing, and DTI at 3, 6, 12, and 24 months postoperatively. DTI was also performed in seven healthy subjects. Fiber tractography was used for 3D segmentation of the whole ACL volume, from which median DTI parameters were calculated. The posterior cruciate ligament (PCL) served as a control. Longitudinal DTI changes were assessed using a linear mixed model, and repeated measures correlations were calculated between DTI parameters and clinical laxity tests. At follow-up, thirteen patients had a stable knee and one patient sustained an ACL rerupture after 12 months postoperatively. The ACL repair showed a significant decrease of FA within the first 12 months after surgery, followed by stable FA values thereafter, while ACL diffusivities decreased over time returning towards normal values at 24 months postoperatively. For PCL there were no significant DTI changes over time. There was a significant correlation between ACL FA and laxity tests (r = -0.42, P = .017). This study has shown the potential of DTI to longitudinally monitor diffusion changes in the ACL following IBLA. The DTI findings suggest that healing of the ACL repair is incomplete at 24 months postoperatively.