Scandinavian journal of medicine & science in sports
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Scand J Med Sci Sports · Dec 2016
Forearm muscle activity is modified bilaterally in unilateral lateral epicondylalgia: A case-control study.
Lateral epicondylalgia (LE) is associated with a reduced wrist extensor muscle activity and altered biomechanics. This study compared the coordination between forearm muscles during gripping in individuals with LE and pain-free controls. Intramuscular electrodes recorded myoelectric activity from extensor carpi radialis brevis/longus (ECRB/ECRL), extensor digitorum communis (EDC), flexor digitorum superficialis/profundus (FDS/FDP), and flexor carpi radialis (FCR), bilaterally, in 15 participants with unilateral LE and 15 pain-free controls. ⋯ These findings indicate forearm muscle activity is modified in LE. It is unknown whether this is cause or effect. Changes in the asymptomatic side may imply involvement of central mechanisms.
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Scand J Med Sci Sports · Dec 2016
We will be champions: Leaders' confidence in 'us' inspires team members' team confidence and performance.
The present research examines the impact of leaders' confidence in their team on the team confidence and performance of their teammates. In an experiment involving newly assembled soccer teams, we manipulated the team confidence expressed by the team leader (high vs neutral vs low) and assessed team members' responses and performance as they unfolded during a competition (i.e., in a first baseline session and a second test session). ⋯ Finally, the results supported a hypothesized mediational model in showing that the effect of leaders' confidence on team members' team confidence and performance was mediated by the leader's perceived identity leadership and members' team identification. In conclusion, the findings of this experiment suggest that leaders' team confidence can enhance members' team confidence and performance by fostering members' identification with the team.
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Scand J Med Sci Sports · Dec 2016
Tendinopathy alters ultrasound transmission in the patellar tendon during squatting.
Measurement of loading patterns of the patellar tendon during activity is important in understanding tendon injury. We used transmission-mode ultrasonography to investigate patellar tendon loading during squatting in adults with and without tendinopathy. It was hypothesized that axial ultrasonic velocity, a surrogate measure of the elastic modulus of tendon, would be lower in tendinopathy. ⋯ While peak velocity was ≈5% higher during both flexion (F1,23 = 5.4, P < 0.05) and extension (F1,23 = 5.3, P < 0.05) phases, there was no significant between-group difference at the midpoint of the movement. There were no significant differences in the rate and magnitude of knee movement between groups. Although further research is required, these findings suggest enhanced baseline muscle activity in patellar tendinopathy and highlight fresh avenues for its clinical management.
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Scand J Med Sci Sports · Sep 2016
Effects of transcutaneous electrical nerve stimulation on quadriceps function in individuals with experimental knee pain.
Knee joint pain (KJP) is a cardinal symptom in knee pathologies, and quadriceps inhibition is commonly observed among KJP patients. Previously, KJP independently reduced quadriceps strength and activation. However, it remains unknown how disinhibitory transcutaneous electrical nerve stimulation (TENS) will affect inhibited quadriceps motor function. ⋯ Post-hoc analysis revealed that hypertonic saline infusion significantly reduced the quadriceps MVC and CAR compared with control sessions (P < 0.05). Sensory TENS, however, significantly restored inhibited quadriceps motor function compared with placebo treatment (P < 0.05). There was a negative correlation between changes in MVC and knee pain (r = 0.33, P < 0.001), and CAR and knee pain (r = 0.62, P < 0.001), respectively.
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Scand J Med Sci Sports · Sep 2016
A new equation to estimate temperature-corrected PaCO2 from PET CO2 during exercise in normoxia and hypoxia.
End-tidal PCO2 (PET CO2 ) has been used to estimate arterial pressure CO2 (Pa CO2 ). However, the influence of blood temperature on the Pa CO2 has not been taken into account. Moreover, there is no equation validated to predict Pa CO2 during exercise in severe acute hypoxia. ⋯ The Jones et al. equation tended to underestimate the temperature corrected (tc) Pa CO2 during exercise in hypoxia, with greater deviation the lower the Pa CO2 tc (r = 0.39, P < 0.05). The new equation has been developed using a random-effects regression analysis model, which allows predicting Pa CO2 tc both in normoxia and hypoxia: Pa CO2 tc = 8.607 + 0.716 × PET CO2 [R(2) = 0.91; intercept SE = 1.022 (P < 0.001) and slope SE = 0.027 (P < 0.001)]. This equation may prove useful in noninvasive studies of brain hemodynamics, where an accurate estimation of Pa CO2 is needed to calculate the end-tidal-to-arterial PCO2 difference, which can be used as an index of pulmonary gas exchange efficiency.