Ovarian and uterine findings in pelvic sonography: comparison between prepubertal girls, girls with isolated thelarche, and girls with central precocious puberty.

OBJECTIVE: To describe pelvic sonographic findings in girls as old as 7 years, to compare prepubertal girls with girls who had isolated thelarche or central precocious puberty, and to verify the accuracy of sonographic variables for distinguishing prepubertal girls from girls with central precocious puberty. METHODS: Ninety-six prepubertal girls and 2 reference groups (8 girls with isolated thelarche and 8 with idiopathic central precocious puberty) were included. Ovaries were classified morphologically as homogeneous, paucicystic, macrocystic, multicystic, and having isolated cysts. Receiver operating characteristic curves were used to choose the best cutoff points. RESULTS: Chronologic and bone age were correlated with uterine length, area, and volume and ovarian volume in prepubertal girls (P < .0001). Ovarian morphologic characteristics in prepubertal girls differed significantly from those of the reference groups (P < .0001). The best cutoff points were uterine length of 4.0 cm, uterine area of 4.5 cm2, uterine volume of 3.0 cm3, and ovarian volume of 1.0 cm3. CONCLUSIONS: Uterine and ovarian growth are proportional to age in prepubertal girls. Mean ovarian volume greater than 1 cm3 showed 100% sensitivity and specificity for discriminating between prepubertal girls and girls with central precocious puberty. Microcysts are common in prepubertal girls, but the presence of 6 or more follicles up to 10 mm in diameter may suggest central precocious puberty in girls younger than 8 years.     

Estimating bone mineral content based on different types of muscle strength tests

The aims of this pilot study were to verify which muscle strength tests better explain bone mineral content (BMC) of the femoral neck and lumbar spine and to develop predictive equations to estimate femoral neck and lumbar spine BMC. Twenty-nine subjects aged 56–76 years old (12 women and 17 men) participated in the study. Femoral neck and lumbar spine BMC was evaluated by Dual X-ray absorptiometry (DXA). Muscle strength measurements included maximal isometric voluntary contractions of knee extensors and flexors, vertical jump, 5-repetition maximum of the leg press (5-RM_LP) and seated leg curl (5-RM_LC), and handgrip strength. Women presented a moderate to strong correlation between femoral neck BMC and 5-RM_LP (r = 0.819), 5-RM_LC (r = 0.879), knee extensors peak torque (r = 0.699), and handgrip strength (r = 0.663), as well as between lumbar spine BMC and the 5-RM_LP test (r = 0.845) and manual grip strength (r = 0.699). For females, the 5-RM_LP and 5-RM_LC tests most fully explained femoral neck BMC (R² = 0.859) and the 5-RM_LP test and body mass explained lumbar spine density (R² = 0.757) for females. Men did not present correlations between BMC and strength variables. For females, the 5-RM_LP and 5-RM_LC variables explained the variations of femoral neck BMC, while 5-RM_LP and body mass explained lumbar spine BMC. Future studies should evaluate a larger sample size and prioritize the strength tests with a greater predictive capacity.     

Muscle function and muscle balance in lower limbs are not impaired in individuals with general joint hypermobility

Sport Sciences for Health - The generalized joint hypermobility (GJH) syndrome is a condition characterized by a connective tissue disorder that may negatively affect the muscle function and muscle...     

EVIDENCE FOR ISOKINETIC KNEE TORQUE ASYMMETRIES IN MALE LONG DISTANCE‐TRAINED RUNNERS

Purpose/Background

Strength asymmetries are related to knee injuries and such injuries are frequently observed among runners. The purpose of this study was to examine whether long‐distance runners have symmetric performance during knee isokinetic testing at two angular velocities.

Methods

Twenty‐three healthy and well‐trained male long‐distance runners performed open‐chain isokinetic trials for assessment of concentric quadriceps and hamstrings contractions at velocities of 60 °·s^‐1 and 240 °·s^‐1. Data were compared between the lower limbs at different velocities.

Results

Peak torque and total work were similar between the limbs. Asymmetry was observed for knee flexor power at 240 °·s^‐1 (237 ± 45 W and 205 ± 53 W, in the preferred and non‐preferred limb, respectively). Asymmetry indexes for flexor power were different between the velocities tested (13.1% and 2.21% for 240 °·s^‐1 and 60 °·s^‐1, respectively).

Conclusion

A limb asymmetry was observed among runners for knee flexor power, mainly at higher angular velocities (240 °·s^‐1). In addition, H/Q ratios were observed to be contraction velocity dependent.

Level of Evidence

3     

Estimation equation of maximum oxygen uptake in taekwondo specific test

Sport Sciences for Health - Progressive specific taekwondo test (PSTT) was designed to evaluate aerobic indicators and maximum frequency kick (FKMAX) in taekwondo athletes. Both can be used as...     

Continuous and intermittent running to exhaustion at maximal lactate steady state: Neuromuscular,biochemical and endocrinal responses

ObjectiveThe aim of the present study was to characterize the neuromuscular, biochemical, and endocrinal responses from a running to exhaustion mode at the maximal lactate steady state intensity during continuous and intermittent protocols.DesignPre-post test measures.MethodsTwelve athletes performed an incremental treadmill test, several constant speed tests to determine the maximal lactate steady state at continuous and intermittent (5:1 ratio) models and two randomized tests until exhaustion at such intensities. Knee extension torque and blood sampling were collected before and immediately after the time to exhaustion tests.ResultsThe results showed a significant decrement (～15%) in torque production after time to exhaustion tests for both exercise models. In addition to neuromuscular impairment, an acute increase of 65% and 38% was observed creatine kinase, during continuous and intermittent running, respectively. Regarding hormonal responses when compared to baseline measurements, cortisol increased by 132% and 121% in the continuous and intermittent protocols, respectively. No correlation was found between biochemical, endocrinal and the neuromuscular variables.ConclusionsThe present findings showed that running until exhaustion performed at maximal lactate steady state, significantly impaired muscle strength and increased hormonal and muscle damage markers in two different protocols (i.e. continuous and intermittent) amongst trained runners.     

Cadence and workload effects on pedaling technique of well-trained cyclists

This study investigated the effects of changing cadence and workload on pedaling technique. Eight cyclists were evaluated during an incremental maximal cycling and two 30-minute submaximal trials at 60 % and 80 % of maximal power output (W (60 %) and W (80 %), respectively). During submaximal 30-minute trials, they cycled for 10 minutes at a freely chosen cadence (FCC), 10 minutes at a cadence 20 % above FCC (FCC + 20 %), and 10 minutes at a cadence 20 % below FCC (FCC - 20 %). Pedal forces and kinematics were evaluated. The resultant force (RF), effective force (EF), index of effectiveness (IE) and IE during propulsive and recovery phase (IEprop and IErec, respectively) were computed. For W (60 %), FCC - 20 % and FCC presented higher EFmean (69 +/- 9 N and 66 +/- 14 N, respectively) than FCC + 20 % (52 +/- 14 N). FCC presented the highest IEprop (81 +/- 4 %) among the cadences (74 +/- 4 and 78 +/- 5 % for FCC - 20 % and FCC + 20 %, respectively). For W (80 %), FCC presented higher EFmean (81 +/- 5 N) than FCC + 20 % (72 +/- 10 N). The FCC - 20 % presented the lower IEprop (71 +/- 7 %) among the cadences. The EFmin was higher for W (80 %) than W (60 %) for all cadences. The IE was higher at W (80 %) (61 +/- 5 %) than W (60 %) (54 +/- 9 %) for FCC + 20 % (all p < 0.05). Lower cadences were more effective during the recovery phase for both intensities and FCC was the best technique during the propulsive phase.     

Effect of mate tea consumption on rapid force production after eccentric exercise: a randomized,controlled, crossover study

Sport Sciences for Health - Unusual eccentric exercise (EE) may affect muscle ability to produce rapid force. Previous study suggested that short-term mate tea (MT) consumption may enhance muscle...     

Photobiomodulation therapy is beneficial in reducing muscle fatigue in Brazilian jiu-jitsu athletes and physically active men

Sport Sciences for Health - Photobiomodulation therapy (PBMT) applied prior to exercise may provide ergogenic effects by delaying the onset of fatigue. The Brazilian jiu-jitsu (BJJ) is a domain...