Background: Intramedullary schwannomas (IS) at cervicomedullary junction (CMJ) are exceedingly uncommon. There is hardly any clinicoradiological marker for preoperative diagnosis and prognostication.
...Case: We report a case of a 17-year-old boy with progressive spastic quadriparesis of six months duration. On radiology, there was a contrast-enhancing lesion expanding the cord extending from the medulla to C5 level. During surgery, the cord was expanded and the tumor was eccentric. Histopathology and immunohistochemistry were suggestive of schwannoma. In view of the ill-defined plane of separation from the normal neural tissue, only subtotal resection could be achieved.
Conclusion: Schwannoma should be considered as a remote differential of intramedullary lesions. The extent of resection should be tailored according to the plane of dissection and intraoperative neuromonitoring guidance. Though a masquerader, schwannoma carries better prognosis than rest of the pathologies.
The purpose of the present investigation was to evaluate differences in Reactive Strength Index Modified (RSI
) and Flight Time to Contraction Time Ratio (FT:CT) during the countermovement jump (CMJ) ...performed without the arm swing (CMJNAS) compared to the CMJ with the arm swing (CMJAS), while exploring the relationship within each variable between jump protocols. A secondary purpose sought to explore the relationship between RSI
and FT:CT during both jump protocols. Twenty-two collegiate basketball players performed both three CMJNAS and three CMJAS on a force plate, during two separate testing sessions. RSI
was calculated by the flight-time (RSI
) and impulse-momentum methods (RSI
). CMJ variables were significantly greater during the CMJAS compared to CMJNAS (
< 0.001). There were large to very large correlations within each variable between the CMJAS and CMJNAS. There were significant positive correlations among RSI
, RSI
, and FT:CT during both the CMJAS (r ≥ 0.864,
< 0.001) and CMJNAS (r ≥ 0.960,
< 0.001). These findings identify an increase in RSI
or FT:CT during the CMJAS, that may provide independent information from the CMJNAS. In addition, either RSI
or FT:CT may be utilized to monitor changes in performance, but simultaneous inclusion may be unnecessary.
Objetivo. El objetivo de esta investigación es evaluar la capacidad de fuerza explosiva de extensión de extremidades inferiores en escolares de educación primaria y analizar las diferencias que ...puedan existir tanto en capacidad de fuerza explosiva de extremidades inferiores como en composición corporal en función del sexo. Material y métodos. En este estudio han participado 90 estudiantes (54 niños y 36 niñas) de educación primaria de un centro educativo urbano de la provincia de Jaén. La media de la edad de los sujetos es de 11,1 ± 0,7 años. Se ha realizado la valoración de la composición corporal y la evaluación de la capacidad de fuerza explosiva de extremidades inferiores mediante salto vertical. La evaluación de la composición corporal se llevó a cabo mediante la plataforma INBODY 230 (Microkaya, Spain). Para medir las variables de los saltos se utiliz ó una plataforma de fuerzas Quattro Jump (Kistler, Suiza) y se realizaron los test de salto CMJ y ABK. Resultados y conclusiones. Los resultados obtenidos en las variables de los test de salto por los participantes se encuentran entre los valores de referencia para sujetos de su edad. Las chicas poseen mayores picos de potencia y de fuerza que los chicos, mientras que estos poseen mayores alturas de vuelo en los saltos. En la impedancia los chicos obtienen mayores porcentajes de músculo y las chicas mayor masa y mayores porcentajes de grasa.
Purpose
The multidimensional role of hamstring muscle group strength in athletic performance and injury prevention is well documented, and nordic hamstring exercise (NHE) is a popular method for the ...development of hamstring strength. Our aim was to examine the EMG characteristics of the eccentric NHE as well as the effects of long-term eccentric NHE training on muscle strength and vertical jump performance in 10- to 11-year-old female handball players.
Methods
Players from the same handball team were randomly assigned to an eccentric NHE training (13 players) or a control group (10 players). Both groups continued their regular handball training routine, but the NHE group performed additional eccentric NHE exercises once or twice a week, with progressively increasing volume, over 20 weeks. To test training effects, countermovement jump (CMJ) height, eccentric hamstring impulse, peak torque, and angle of peak torque were evaluated before, during and after the training period. In the pre-exercise test, EMG activity of the medial and lateral hamstring muscle was also assessed during NHE.
Results
Hamstring activities ranged between 98 and 129%. Lateral hamstring activity was greater than medial only in the right leg during NHE. Eccentric hamstring impulse improved in both legs at 10 weeks in both groups. Then, at 20 weeks, it remained unchanged in the NHE but decreased in controls. A similar adaptation was seen in eccentric hamstring torque, without change in the optimum knee angle. CMJ height improved only in the NHE.
Conclusion
It is concluded that NHE activates the hamstring musculature effectively, and a favourable mechanical adaptation to long-term NHE exercise in girls can be triggered as early as 11 years of age.
(1) Background: Leg length discrepancy (LLD), regardless of its origin, is a very common pathology that can contribute to low back pain. Various authors have pointed out its relationship with the ...lack of activation of both the gluteus medius (GM) and the ipsilateral erector spinae (ES). The purpose of this study was to identify the activation of the ES and GM with different simulated LLDs, correlating this activation with LBP. In turn, we evaluated whether ES and GM activity has an effect on jumping ability using a CMJ test. (2) Method: A sample of healthy subjects was selected to whom an artificial LLD was applied using 0.5, 1, and 1.5 cm insoles. These three heights were measured using EMG while the subjects walked and performed a counter movement jump (CMJ). The measurements of the insole heights were carried out in random order using a Latin square. Muscle activation patterns were recorded for 30 s at each of the insole heights while the patients walked at 5.7 km/h and they were compared with the maximum voluntary contraction (MVC), both on the ipsilateral and contralateral sides. These muscles were then measured under the same circumstances during the performance of the CMJ. (3) Results: We found statistically significant differences in the flight heights in both the CMJ and DJ. In the comparison, significant differences were found in the flight heights of the CMJ and the DJ using the 5 mm insoles, and in the case of the DJ, also without insoles, with respect to the MVC. We found statistically significant differences in the activation of the GM with the differences in insoles, but not in the activation of the Es in relation to the different insole heights. (4) Conclusions: Insoles of different heights caused activation differences in the medius on the side where the insoles were placed. We can relate this difference in activation to LBP. In relation to the ES, no significant differences were found in the activation of the ipsilateral side of the insole.
Nowadays, various methods are used for acute performance enhancement. The most recent of these is tissue flossing, which is becoming increasingly popular for both performance enhancement and ...rehabilitation. However, the effects of flossing on athletic performance have not been clearly demonstrated, which could be due to differences in the methodology used. In particular, the rest periods between the end of the preconditioning activity and the performance of the criterion task or assessment tools varied considerably in the published literature. Therefore, the present study aimed to investigate the effects of applying tissue flossing to the thigh on bilateral countermovement jump performance and contractile properties of vastus lateralis (VL) muscle. Nineteen recreational athletes (11 males; aged 23.1 ± 2.7 years) were randomly assigned to days of flossing application (3 sets for 2 min of flossing with 2 min rest between sets) with preset experimental pressure (EXP = 95 ± 17.4 mmHg) or control condition (CON = 18.9 ± 3.5 mmHg). The first part of the measurements was performed before and after warm-up consisting of 5 min of cycling followed by dynamic stretching and specific jumping exercises, while the second part consisted of six measurement points after flossing application (0.5, 3, 6, 9, 12, 15 min). The warm-up improved muscle response time (VL = -5%), contraction time (VL = -3.6%) muscle stiffness (VL = 17.5%), contraction velocity (VL = 23.5%), jump height (13.9%) and average power (10.5%). On the contrary, sustain time, half-relaxation time and take-off velocity stayed unaltered. Flossing, however, showed negative effects for muscle response time (F = 18.547,
< 0.001), contraction time (F = 14.899,
< 0.001), muscle stiffness (F = 8.365,
< 0.001), contraction velocity (F = 11.180,
< 0.001), jump height (F = 14.888,
< 0.001) and average power (F = 13.488,
< 0.001), whereas sustain time, half-relaxation time and take-off velocity were unaffected until the end of the study protocol regardless of condition assigned and/or time points of the assessment. It was found that the warm-up routine potentiated neuromuscular function, whereas the flossing protocol used in the current study resulted in fatigue rather than potentiation. Therefore, future studies aimed to investigate the dose-response relationship of different configurations of preconditioning activities on neuromuscular function are warranted.
Taurine (2-aminoethanesulfonic acid) is a semi-essential sulphur-containing amino acid abundant in skeletal muscle. Taurine supplementation is popular among athletes and has been purported to enhance ...exercise performance. This study aimed to investigate the ergogenic effects of taurine supplementation on anaerobic (Wingate; WanT) performance, blood lactate, ratings of perceived exertion (RPE), and countermovement vertical jump (CMJ) in elite athletes. For this study, randomized, double-blind, placebo-controlled crossover designs were used. Thirty young male speed skaters were randomly assigned to either taurine (TAU; single dose of 6 g) or placebo (PLAC; single dose of 6 g) 60 minutes before testing. Following a 72-hour washout, period participants completed the opposite condition. TAU improved peak (Δ% = 13.41, p < 0.001, d = 1.71), mean (Δ% = 3.95, p = 0.002, d = 1.04), and minimum power output (Δ% = 7.89, p = 0.034, d = 0.48) compared to placebo. Further, RPE (Δ% = -10.98, p = 0.002, d = 0.46) was significantly lower following the WanT in the TAU condition compared to placebo. There were no differences between conditions for the countermovement vertical jump. In conclusion, acute TAU supplementation augments anaerobic performance in elite speed skaters.
Examine the influence of test modality, season stage, match load and physical qualities on the interpretation of neuromuscular function (NF) post Australian Rules Football (ARF) matches.
Repeated ...measures design.
Thirty-two elite ARF players’ NF was assessed 72h following competitive matches (7±2) via the counter movement jump (CMJ) and isometric mid-thigh pull (IMTP). Influence of season stage, external load parameters (GPS; 10Hz) and moderating influences of lower body strength (LBS), lower body power (LBP) and intermittent exercise capacity upon NF recovery were assessed using linear mixed effects models.
Moderate negative seasonal trends were evident for both rate of force development (RFD) 0−100ms (d=−0.86, 95%, CI: ±0.57) and 0−200ms (d=−0.76, CI: ±0.64). Significant but trivial effects of match load were observed between one standardised unit increase in high speed running (HSR) versus CMJ: Force at zero velocity (d=0.12, CI: ±0.12), and sum of high intensity accelerations and CMJ: Eccentric deceleration RFD (d=−0.18, CI: ±0.14). Accounting for baseline LBS better explained (weight of evidence: W=87%) seasonal trends observed in IMTP: peak force, with lower LBS showing greater capacity for improvement. Positive moderating influences were observed with baseline LBS and LBP (W=91 & 75%) on CMJ: eccentric mean power responses to HSR, and CMJ: jump height responses to very-HSR, respectively.
Interpretation of athlete NF responses is complicated by the inconsistent and interacting influence of contextual factors (assessment modality, stage of season, load), in-particular higher baseline LBS and LBP may improve acute load related responses of NF.
In this study, we aimed to assess the countermovement jump (CMJ) using a developed instrument encompassing an off-the-shelf Inertial Measurement Unit (IMU) in order to analyze performance during the ...contraction phase, as well as to determine the jump height and the modified reactive strength index (RSImod), using force plate (FP) data as reference. Eight athletes (six males and two females) performed CMJs with the IMU placed on their fifth lumbar vertebra. Accuracy was measured through mean error (standard deviation), correlation, and comparison tests. The results indicated high accuracy, high correlation (r), and no statistical differences between the IMU and the FP for contraction time (r = 0.902; ρ < 0.001), negative impulse phase time (r = 0.773; ρ < 0.001), flight time (r = 0.737; ρ < 0.001), jump time (r = 0.708; ρ < 0.001), RSImod (r = 0.725; ρ < 0.001), nor minimum force (r = 0.758; ρ < 0.001). However, the values related to the positive impulse phase did not have the expected accuracy, as we used different devices and positions. Our results demonstrated that our developed instrument could be utilized to identify the contraction phase, jump height, RSImod, and minimum force in the negative impulse phase with high accuracy, obtaining a signal similar to that of an FP. This information can help coaches and athletes with training monitoring and control, as the device has simpler applicability making it more systematic.
El objetivo de este estudio fue comprobar el efecto de dos periodos de preparación diferenciados por los medios de entrenamiento de la fuerza (con/sin carga externa añadida-pesas), en deportistas de ...natación sincronizada. Se valoraron las variables rendimiento (altura) en salto vertical (CMJ) y los test específicos de boost y tintorera. Un grupo de nadadoras de categoría infantil/júnior (14 ± 1 años), sin experiencia en el entrenamiento de fuerza, fueron las participantes en el estudio (n = 10). Durante el primer periodo de preparación se trabajó la fuerza sin carga externa añadida. En el segundo, se trabajó la fuerza con carga externa añadida (cargada, sentadilla y saltos con carga). Las deportistas fueron testadas al finalizar la pretemporada (datos referencia) y tras cada periodo de intervención (14 semanas). El análisis estadístico mostró cambios significativos en el boost (p < .05) y en el CMJ (p < .01) tras el segundo periodo. No se encontraron cambios significativos en la tintorera. No se observó ningún cambio significativo durante el primer periodo. Se encontró relación positiva significativa entre el boost y la tintorera (p < .05) y entre el CMJ y el boost (p <.01) en todas las ocasiones que se midieron. El CMJ y la tintorera muestran correlación positiva pero nunca llega a la significación. Se encontró correlación significativa (r = .643; p ≤ .05) entre los cambios en CMJ y en la tintorera y, próxima a la significación, con el boost (r = .602; p = .065). Los resultados muestran un mayor efecto del entrenamiento con carga externa añadida sobre el rendimiento de las nadadoras en el CMJ, existiendo transferencia sobre las acciones específicas, lo que probablemente lleve a la mejora del rendimiento competitivo.
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