| 1. |
- Blomqvist, Sven, Universitetslektor, 1964-, et al.
(author)
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Evaluating Physical Workload by Position During Match in Elite Bandy
- 2018
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In: Journal of Strength and Conditioning Research. - : Lippincott Williams & Wilkins. - 1064-8011 .- 1533-4287. ; 32:9, s. 2616-2622
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Journal article (peer-reviewed)abstract
- To improve current understandings of physical workload (WL) in elite bandy, 10 bandy players were monitored for heart rate (HR) during 13 matches over 1 championship season. Participants were divided into 5 subgroups according to playing position-libero, defender, halves, midfielder, and forward. Heart rate measurements were analyzed with 2 different methods to compute physical WL-(a) percentage of total time spent in different HR zones (HRres) and (b) WL based on the Edwards method. Also determined was the time spent at HR levels above the lactate threshold (LT). A one-way analysis of variance was used for analysis. For WL, according to the Edwards method, significant differences (p = 0.05) were shown between the groups with defenders presenting the highest scores, and forwards and liberos the lowest. A significant difference (p = 0.05) was found between liberos and halves and the other positions as to how much time they spent in zone 70-80% of HRres. In 91-100% of HRres, there was a distinct difference between defenders and the other positions and also forwards differed significantly from liberos, defenders, and halves (p = 0.05). The libero spent only 1% of the time over the LT, whereas the midfielder spent approximately 27% of the time over the LT. Overall, defenders showed the greatest WL during a match and liberos the lowest. The practical implications of these findings can help coaches and trainers design training methods specific to each position and individualized training sessions for each player in elite bandy.
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| 2. |
- Crenshaw, Albert G., et al.
(author)
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Reliability of near-infrared spectroscopy for measuring forearm and shoulder oxygenation in healthy males and females
- 2012
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In: European Journal of Applied Physiology. - : Springer. - 1439-6319 .- 1439-6327. ; 112:7, s. 2703-2715
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Journal article (peer-reviewed)abstract
- This study determined the day-to-day reliability of NIRS-derived oxygenation responses (a dagger StO(2)%) for isometric contractions and for cuff occlusion. Twenty-four subjects (12 males and 12 females) were tested for 2 days (4-6 days interval). Variables generated were: (1) a dagger StO(2)% for isometric contractions (10, 30, 50 and 70% MVC) for descending trapezius (TD) and extensor carpi radialis (ECR) muscles; (2) slope changes in total haemoglobin (HbTslope) and deoxyhaemoglobin (HHbslope) for the ECR using upper arm venous (VO, 50 mmHg) and arterial occlusion (AO, 250 mmHg); (3) recovery slopes (Rslope) for oxygen saturation (StO(2)) following isometric contractions and AO. For each variable, an intraclass correlation (ICC) was calculated to assess the ability to differentiate between subjects, and limits of agreement (LOA) were computed to assess day-to-day consistency of the measurement. ICCs for Delta StO(2)% were lowest at 10% MVC for both ECR (0.58) and TD (0.55), and highest at 30% MVC for ECR (0.95) and at 70% MVC for TD (0.79). For both muscles, LOA for Delta StO(2)% was lowest at 10% and highest at 50 and 70% MVC. ICC for HbTslope was 0.17. For HHbslope ICC was higher for AO (0.83) than for VO (0.73), and LOA was lower for AO. For the ECR Rslope ICCs ranged from 0.88 to 0.90 for contraction, but was lower for AO (0.33); LOA was lowest at 70% MVC. For trapezius Rslope ICCs ranged from 0.63 to 0.73 and LOA was lowest at 30% MVC. For this study, establishing reliability data for the ECR and TD and including variables commonly reported are expected to have meaning for future NIRS studies of work-related upper-extremity pain as well as for other NIRS research and clinical applications.
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| 3. |
- Elcadi, Guilherme H, 1966-, et al.
(author)
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No differences in oxygenation in the forearm and shoulder of patients with work-related muscle pain and healthy subjects during a low-load sustained contraction
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Other publication (other academic/artistic)abstract
- A frequently ascribed symptom associated to work-related muscle pain (WRMP) is muscle fatigue. Studies investigating oxygenation and hemodynamics in association to fatigue development in the muscles of patients with WRMP are sparse. Inadequate oxygen consumption and/or inadequate blood supply can influence the ability of the muscles to withstand fatigue. In this study we applied near-infrared spectroscopy (NIRS) and electromyography (EMG) to investigate oxygenation, hemodynamics and muscle activity in the extensor carpi radialis (ECR) and trapezius (TD) muscles of patients with WRMP and healthy controls. Eighteen patients with diffuse neck-shoulder-arm pain and 17 controls (matched in age and sex) were equipped with NIRS and EMG probes. After determination of maximal voluntary contraction (MVC) a sustained contraction of 15% MVC was performed with a cutoff for the maximum time of 12 min. Variables generated were StO2% and HbT from NIRS and RMS%max and MPF from EMG during the contraction. T tests and Mann-Whitney tests were used for analyzes of differences in MVC and endurance times. Full factorial repeated measures analyses of variance (ANOVA) were used to assess differences between patients and controls in NIRS and EMG parameters over time. Results showed no differences in MVC between patients and controls. We found, however, a shorter endurance time for patients compared to controls. There were no significant differences in StO2%, HbT, RMS and MPF responses during contraction between groups for the ECR. For the TD there was a group effect for StO2% with patients showing a lower level at rest and throughout the contraction. For the ECR and TD oxygenation, hemodynamics, RMS and MPF there were no straightforward differences between patients and controls that could explain the differences in endurance time. Therefore, we conclude that the shorter endurance time seen in the present study was not measurable by physiological indicators investigated in this group of patients.
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| 4. |
- Elcadi, Guilherme H., 1966-, et al.
(author)
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Oxygenation and Hemodynamics Do Not Underlie Early Muscle Fatigue for Patients with Work-Related Muscle Pain
- 2014
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In: PLOS ONE. - : PLOS (Public library of science). - 1932-6203. ; 9:4
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Journal article (peer-reviewed)abstract
- Patients suffering from work-related muscle pain (WRMP) fatigue earlier during exercise than healthy controls. Inadequate oxygen consumption and/ or inadequate blood supply can influence the ability of the muscles to withstand fatigue. However, it remains unknown if oxygenation and hemodynamics are associated with early fatigue in muscles of WRMP patients. In the present study we applied near-infrared spectroscopy (NIRS) on the extensor carpi radialis (ECR) and trapezius (TD) muscles of patients with WRMP (n = 18) and healthy controls (n = 17). Our objective was to determine if there were group differences in endurance times for a low-level contraction of 15% maximal voluntary contraction (MVC) -sustained for 12-13 min, and to see if these differences were associated with differences in muscle oxygenation and hemodynamics. At baseline, oxygen saturation (StO(2)%) was similar between groups for the ECR, but StO2% was significantly lower for TD for the WRMP patients (76%) compared to controls (85%) (P < 0.01). Also, baseline ECR blood flow was similar in the two groups. For both muscles there were a larger number of patients, compared to controls, that did not maintain the 15% MVC for the allotted time. Consequently, the endurance times were significantly shorter for the WRMP patients than controls (medians, ECR: 347 s vs. 582 s; TD: 430 s vs. 723 s respectively). Responses in StO(2)% during the contractions were not significantly different between groups for either muscle, i.e. no apparent difference in oxygen consumption. Overall, we interpret our findings to indicate that the early fatigue for our WRMP patients was not associated with muscle oxygenation and hemodynamics.
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| 5. |
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| 6. |
- Elcadi, Guilherme H., 1966-, et al.
(author)
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Shoulder and forearm oxygenation and myoelectric activity in patients with work related muscle pain and healthy subjects
- 2013
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In: European Journal of Applied Physiology. - New York : Springer. - 1439-6319 .- 1439-6327. ; 113:5, s. 1103-1115
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Journal article (peer-reviewed)abstract
- We tested hypotheses of (i) reduced oxygen usage, oxygen recovery, blood flow and oxygen consumption; and (ii) increased muscle activity for patients diagnosed with work related muscle pain in comparison to healthy controls. Oxygenation was measured with near infrared spectroscopy (NIRS), and muscle activity with EMG for the extensor carpi radialis (ECR) and trapezius descendens (TD) muscles. Eighteen patients with diffuse neck-shoulder-arm pain and seventeen controls (matched in age and sex) were equipped with NIRS and EMG probes. After determining an individual’s maximum voluntary contraction (MVC) force, short term (20 sec) isometric contractions for the ECR and TD of 10%, 30%, 50% and 70% MVC generated ∆StO2% and StO2% recovery (Rslope) from NIRS, and RMS%max from EMG signals. In addition, upper arm venous (VO) and arterial (AO) occlusions generated slopes of total hemoglobin (HbTslope) and deoxyhemoglobin (HHbslope) for the resting ECR as surrogates of blood flow and oxygen consumption, respectively. Mixed Model analyses, t-tests, and Mann-Whitney test were used to assess differences between groups. There was no significant difference in MVC between groups for either muscle. Also, ∆StO2%, Rslope for either muscle, and ECR-HbTslope were not different between groups, thus our hypotheses of reduced oxygen use, recovery, and blood flow for patients were not confirmed. However, patients had a significantly lower ECR-HHbslope confirming our hypothesis of reduced consumption. Further, there was no difference in RMS%max during contractions meaning that the hypothesis of increased activity for patients was not confirmed. When taking into account the number of NIRS variables studied, differences we found between our patient group and healthy controls (i.e. in forearm oxygen consumption and shoulder oxygen saturation level) may be considered modest. Overall our findings may have been impacted by the fact that our patients and controls were similar in muscle strength, which is in contrast to previous studies.
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| 7. |
- Elcadi, Guilherme H., 1966-, et al.
(author)
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The relationship between oxygenation and myoelectric activity in the forearm and shoulder muscles of males and females
- 2011
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In: European Journal of Applied Physiology. - : Springer. - 1439-6319 .- 1439-6327. ; 111, s. 647-658
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Journal article (peer-reviewed)abstract
- The aim was to investigate the relationship between oxygen saturation (StO(2)%) measured with near-infrared spectroscopy (NIRS) and myoelectric activity (root mean square, RMS) for the extensor carpi radialis (ECR) and trapezius muscles. In addition, gender differences were examined for submaximal (10-70% MVC) and sustained (10% MVC for 5 min) isometric contractions. Thirteen males and 15 females participated. Changes in StO(2)% (a dagger StO(2)%) and RMS, expressed as percentages of maximum, were calculated for each submaximal contraction. A good correlation between a dagger StO(2)% and RMS was seen for the ECR (r = -0.53) and a moderate correlation seen for the trapezius muscle (r = -0.44). The ANOVA showed a significant decrease in ECR-a dagger StO(2)% over force with females demonstrating a tendency for larger changes than males. ECR-RMS increased over force with no impact of gender. For the trapezius, a dagger StO(2)% decreased over force but was not gender dependent. Trapezius-RMS increased over force with females demonstrating a tendency for greater change than males. For the sustained contraction, ECR-StO(2)% changed over time but was not gender dependent. ECR-RMS increased over time with females showing a greater response than males. Trapezius-StO(2)% changed over time and differed between genders, i.e., males increased while females decreased. RMS increased over time similarly for both genders. In conclusion, our data show that the ECR and trapezius aerobic demands during isometric contractions are negatively correlated to electromyography (EMG) RMS. The present study also suggests some gender specificity for forearm and shoulder myoelectric activity and oxygenation for submaximal and sustained contractions.
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| 8. |
- Esteves, G. J., et al.
(author)
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Effect of transcranial direct current stimulation on supramaximal intermittent exercise performance
- 2019
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In: Motriz. Revista de Educacao Fisica. - : Universidade Estadual Paulista - UNESP. - 1415-9805. ; 25:4
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Journal article (peer-reviewed)abstract
- Aims: Our purpose was to determine whether Transcranial Direct Current Stimulation (tDCS) improves performance in untrained individuals for supramaximal intermittent exercise. Methods: In a cross-over design, 11 healthy male subjects (26.8 ± 4.6 years) performed four Wingate trials after 20 minutes of anodal or sham tDCS over the left Insular Cortex (IC). For performance indexes, Relative Peak Power (RPP), Relative Average Power (RAP) and Fatigue Index (FI) were computed. Also, a Rating of Perceived Exertion (RPE) and Electromyography (EMG) signal were used to assess central and muscle fatigue development. Results: There was a significant difference over trials on all performance indexes, but there were no significant condition x trial interactions for any of the indexes. RPE increased significantly over trials, but there was no condition x trial interaction. There was no significant difference over trials on EMG for the rectus femoris and vastus medialis muscles; however, EMG decreased over trials for the vastus lateralis muscle. Furthermore, there was no condition x trial interaction on the EMG signal for any of the muscles.Conclusion: Our findings suggest that the anodal tDCS technique has no impact on physical performance, perceived exertion nor muscle fatigue development for supramaximal intermittent exercise.
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