Double Jumps Research Articles

Heel Injury-Figure Skate

HISTORY: A nine year old female figure skater presented with 6 weeks of atraumatic right foot pain. She recently started training double jumps prior to the onset of pain. Pain was located on the plantar side of the right midfoot and she initially noticed it following practices. Weight bearing increased her pain and eventually it hurt during practice as well as after practice . No changes in training time or frequency. She has been figure skating for two years. No history of previous foot injuries or bone stress injuries. No family history of osteoporosis. Her past medical history is significant for chronic Lyme’s disease. PHYSICAL EXAM: Ht 4' 6" (1.372 m) | Wt 69 lb (31.3 kg) | BMI 16.64 kg/m2 (56 percentile), Healthy and NAD. Accompanied by her mother. Examination: Inspection: Neutral foot type. Normal alignment of lower extremities. There was no redness, swelling, or skin changes. Palpation: moderate tenderness on the right plantar mid foot. Range of motion: there was full active range of motion of the ankle, without significant pain. Strength: Muscle strength (ankle plantarflexion, dorsiflexion, inversion, eversion) full. Special tests: Fracture test (tap, percussion, bump) negative, squeeze test negative, anterior drawer test negative, Talar tilt test negative, Stress test negative, Thompson test negative. DIFFERENTIAL DIAGNOSIS: 1.Navicular bone stress injury 2.Tarsal coalition 3.Anterior tibialis tendinopathy 4.Posterior tibialis tendinopathy 5.Bone tumor 6.Nerve entrapment 7.Heel pad syndrome 8.Sever disease TEST AND RESULTS: 1.Ankle X-ray- No obvious fracture or callus 2.MRI Ankle- bone marrow edema in the neck of the calcaneus 3.DXA- Normal bone density FINAL DIAGNOSIS: Calcaneus bone stress injury TREATMENT AND OUTCOMES: 1.Decreased activity level 2.Non-weight bearing on crutches for 2 weeks 3.Walking boot for 3 weeks with partial weight bearing on crutches 4.PT 1-2x/ week for 2-3 weeks 5.Vitamin D 2000 IU everyday 6.Partial weight bearing to full weight bearing as tolerated 7.Gradual return to sports after 12 weeks of injury, when she did not have pain with ambulation, and repeat MRI showed no evidence of residual bone marrow edema.

ALÇAK VE ORTA YÜKSEKLİKTEKİ BİNALARDA ASANSÖR KAT ÜNİTELERİNİN KONTROLÜ İÇİN YENİ BİR ÇOK ATLAMALI KABLOSUZ AĞ ÖNERİSİ

Wired communication systems used to control elevator floor fixtures have problems due to huge amount of cables used in implementation, long installation time, long troubleshooting time and chronic faults. This paper proposes a double-jump multi-hop wireless network for low-rise and medium-rise buildings to control elevator floor fixtures using wireless short packet protocol (WSP). Telegram success rate, telegram intensity, hop time and signal power measurements have been performed on the proposed network. Experimental results emphasize that telegram intensity of about 75 telegram/s guarantees 100 % telegram success rate. Average hop times of 16.1 ms and 17.5 ms for the first and second hops have been measured respectively and found to be enough for low-rise and medium-rise buildings. Signal power measurements show that proposed network may be capable of performing even triple jumps or more instead of double jumps contributing to the speed, telegram intensity and the performance of the network .

Pricing multi-asset American option under Heston-CIR diffusion model with jumps

In this paper, we study Heston-CIR model with the double exponential jumps. We first verify the existence and uniqueness of the solution related to the price process of the model. Next, we calibrate the option prices resulting from this model to a set of observed index options. At last, by applying the Least Square Monte-Carlo algorithm (LSM), we numerically examine the multi-asset American style put options under our considered model.

First Crossing Times of Telegraph Processes with Jumps

The paper presents exact formulae related to the distribution of the first passage time τx of the jump-telegraph process. In particular, the Laplace transform of τx is analysed, when a jump component is in the opposite direction to the crossing level x > 0. The case of double exponential jumps is also studied in detail.

THE POST ACTIVATION POTENTIATION EFFECT OF TWO DIFFERENT CONDITIONING STIMULI ON DROP JUMP PARAMETERS ON YOUNG FEMALE ARTISTIC GYMNASTS

The purpose of this study was to examine the post activation potentiation (PAP) effect of two different conditioning stimuli (CS) on drop jump (DJ) parameters on young female gymnasts. Thirty young female artistic gymnasts, aged 8 to 13 years old performed two protocols of either double tuck jumps (DTJ: 2 sets of 5 repetitions) or legs blocking action (LBA: 2 sets of 5 repetitions) in a within-subject randomized design. Before and immediately after the PAP treatment and 4, 8, 12, and 16 min after, jumping ability was measured by performing a drop jump (DJ). Statistical analysis revealed significant interaction effect between the two CS for DJ height (p < 0.002), time flight (p < 0.002) and take-off velocity (p < 0.003). Furthermore, significant main effect was found for protocol on DJ height (p < 0.001) and time flight (p < 0.001). It is recommended to the sports experts to include similar condition stimuli in the warm-up procedure, in order to improve their jumping performance. Conclusive both CS cause PAP phenomenon but the specialized CS produces higher rates of improvements in young female artistic gymnasts.

Mobility-aware application protocols

Temporal/spatial disruptions and IP changing caused by host mobility lead the user applications to fail. This remains a problem due to the ossification of the TCP/IP protocol stack and the lack of support of existing solutions in enabling connection failure tolerance at application layer. To preserve integrity and transmission consistency upon erroneous communication events caused by host mobility, enabling mobility awareness is a key requirement for the current user applications. In this paper, we provide a comprehensive study on mobility-aware application protocols that ensure reliability and resiliency for long-lived TCP sessions established between clients and severs that migrate across different wireless IP networks on the Internet. To this end, we modeled and simulated such protocols through general-purpose state machines, which we conceived regarding the Socket semantic to resume session from broken connections. Simulations results revealed how internal and external factors, i.e., protocol design decisions and mobile environment conditions, respectively, can and cannot influence performance. When comparing results with TCP-Migrate – a well-known transport layer mobility protocol, handover delays in application protocols are longer in single jumps between mobile client and stationary server, but shorter in double jumps, when both client and server are mobile entities.

An efficient pricing algorithm for American options with double stochastic volatilities and double jumps

The purpose of the paper is to provide an efficient pricing algorithm for American options with stochastic volatilities and jumps. This paper extends the double Heston model with double exponential jumps and derives the characteristic function of the model by Feynman–Kac theorem. With the obtained characteristic function, this paper also extends the Fourier-cosine expansion method for pricing Bermudan options to the model. Based on the COS method, this paper approximates American options by using Richardson extrapolation schemes on a series of Bermudan options and provides a pricing algorithm for American put options. Numerical results show that the proposed pricing algorithm is efficient, especially for short-term American put options.

COMPARISON OF THE ‘BACK IN ACTION’ TEST BATTERY TO STANDARD HOP TESTS AND ISOKINETIC KNEE DYNAMOMETRY IN PATIENTS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Limb symmetry after anterior cruciate ligament reconstruction may be evaluated using maximal strength and hop tests, which are typically reported using Limb Symmetry Indices (LSIs) which may overestimate function. The purpose of this study was to compare the Back in Action (BIA) test battery to standard hop and muscle strength tests used to determine readiness to return to sport (RTS). Prospective cohort. Over two test sessions, 40 ACLR patients were assessed at a mean 11.3 months post-surgery. Initially, participants completed the 6 m timed hop and the single, triple and triple crossover hops for distance, and isokinetic knee extensor and flexor strength assessment. The second session involved completion of the BIA battery, including stability tests, single and double leg countermovement jumps (CMJ), and plyometric, speedy jump, and quick feet tests. Pass rates for test batteries were statistically compared, including the BIA, a four-hop battery (≥90% LSI in every one of the four hop tests) and a combined 4-hop and strength battery (≥90% LSI in every one of the four hop tests, as well as ≥90% for both peak knee extensor and flexor strength). LSI differences between the four standard hop tests and the BIA single limb functional tests (the single limb CMJ and the speedy jump test) were evaluated. Significantly less participants passed the BIA battery (n = 1, 2.5%), compared with the four-hop test battery (n = 27, 67.5%) (p<0.001) and the four-hop test and isokinetic strength battery (n = 17, 42.5%) (p<0.001). Collectively, LSI's for the standard hop tests were significantly higher than the BIA functional single limb tests (difference = 12.9%, 95% CI: 11.1% to 14.6%, p<0.001). The BIA test battery appears to include some single limb functional tests that are more physically challenging than standard hop and isokinetic strength tests, highlighted by the significantly lower mean LSI's during the single limb BIA tests and the lower pass rate when employing the BIA protocol. Level 4, case series.

Effect of Cognitive Dual Tasks on Lower Extremity Kinematics and Ground Reaction Force during Repeated Tuck Jump Landings

Many sports-related injuries occur due to a combination of physical, high joints load during sport-specific maneuvers and cognitive factors, such as keeping other players or the ball in short-term memory. This addition of cognitive challenges can degrade physical performance and increase joint loading. However, previous studies have focused on a single movement and it is unknown how cognitive load influences repeated landing that better simulate the continuous demand of athletic performance. PURPOSE: To determine if a cognitive challenge during tuck jumping affect lower extremity landing biomechanics. METHODS: Recreational collegiate athletes (N=20, 71.7±11.9kg, 171.1±9.7cm) participated in this study. A baseline: BASE condition of repeated tuck jumps and a cognitive: COG condition of tuck jumps while performing an addition problem from a stream of digits on a computer screen. The tuck jump consisted of 3 sets of 10 seconds repeated double leg vertical tuck jumps. Dominant-side sagittal plane lower extremity angular kinematics and vertical ground reaction forces (VGRF: 1,000 Hz) were compared between the two conditions paired t-tests (p<.05). RESULTS: COG, compared to the BASE, resulted in increased ankle angle (30.1±1.7° and 29.3±0.7°) and decreased knee angle (20.5±0.6° and 21.5±0.6°) at initial contact. Also, decreased ankle (21.8±1.4° and 22.4±1.0°) and knee (63.0±0.7° and 67.9±0.9°) maximum angle occurred. Additionally, COG resulted in an increased ankle (52.6±0.9° and 51.6±0.9°), decreased knee (42.5±1.2° and 46.4±0.8°) and hip (31.7±1.1° and 33.0±0.7°) displacements. No significant differences were found in VGRF between conditions. CONCLUSION: We surmised that COG, compared to the BASE, change lower extremity biomechanics that may increase injury risk and knee loading. The more extended knee position at initial contact and reduced sagittal displacement during the COG condition may contribute to increased injury risk when under cognitive load. However, greater ankle displacement during the COG condition may be adaptation strategy to protect the knee under cognitive load.

Dynamic conductivity modified by impurity resonant states in doping three-dimensional Dirac semimetals

The impurity effect is studied in three-dimensional Dirac semimetals in the framework of a T-matrix method to consider the multiple scattering events of Dirac electrons off impurities. It has been found that a strong impurity potential can significantly restructure the energy dispersion and the density of states of Dirac electrons. An impurity-induced resonant state emerges and significantly modifies the pristine optical response. It is shown that the impurity state disturbs the common longitudinal optical conductivity by creating either an optical conductivity peak or double absorption jumps, depending on the relative position of the impurity band and the Fermi level. More importantly, these conductivity features appear in the forbidden region between the Drude and interband transition, completely or partially filling the Pauli block region of optical response. The underlying physics is that the appearance of resonance states as well as the broadening of the bands leads to a more complicated selection rule for the optical transitions, making it possible to excite new electron-hole pairs in the forbidden region. These features in optical conductivity provide valuable information to understand the impurity behaviors in 3D Dirac materials.

Forward starting options pricing with double stochastic volatility, stochastic interest rates and double jumps

We present an extension of double Heston stochastic volatility model by introducing CIR stochastic interest rate and double exponential jumps in the stock price process. We derive the characteristic function and forward characteristic function of the log asset price and thereby forward starting options are well evaluated by the COS method. We also provide efficient simulation of the proposed model and Monte Carlo solutions to forward starting options pricing based on the QE scheme. Numerical results show that the COS method is fast and efficient for pricing forward starting options.

Effect of Fatigue on Lower Extremity Biomechanics during Repeated Vertical Jumps in College-Aged Females

Anterior cruciate ligament (ACL) injuries are common in females, and most non-contact ACL injuries occur during landing or cutting movements. Also, fatigue has been linked to an increased risk of injury. Accordingly, significantly more injuries occur during the latter portions of game performance, according to several epidemiological studies. However, a scarce amount of research exists regarding the effects of neuromuscular fatigue on landing biomechanics. We surmised that FL would cause abnormal lower extremity biomechanics. PURPOSE: To determine if a 60-second continuous bout of jumping affects lower extremity landing biomechanics in females. METHODS: Recreational female athletes (n=10; 63.9±6.5kg, 170.5±3.1cm) participated in this study. Participants performed established fatigue protocol: double leg vertical jumps every three seconds for 60 seconds. Participants were required to touch a suspended horizontal bar during each jump, with the bar height set by having participants hang from the bar and adjusting it until the height from the midpoint of the lateral malleolus to the ground was 0.4 m. The first three consecutive jumps from the first and last 10 seconds were chosen for data analysis. Reflective marker coordinates were reconstructed from locations captured from 7 cameras (240 Hz). Dominant-side lower extremity angular joint kinematics and ground reaction forces (GRF: 1,200 Hz) were compared between the non-fatigue landings (NFL) and fatigue landings (FL) using paired t-tests (p<.05). RESULTS: FL, compared to NFL, resulted in increased knee abduction angle (1.6±3.9° and 0.6±2.8°) and decreased knee flexion angle (2.7±5.2° and 4.0±6.3°) at initial contact (IC). An increased trunk maximum flexion angle (15.5±7.6° and 10.0±5.2°) and knee flexion displacement (58.7±12.8° and 55.6±13.6°) also occurred. Additionally, FL also resulted in a reduction in vertical GRF peak magnitude (1.47±0.24 N[BULLET OPERATOR]kg-1 and 1.75±0.26 N[BULLET OPERATOR]kg-1). CONCLUSION: At IC, both an extended knee position and greater knee abduction angle have been associated with an increase in ACL injury risk and loading. However, a decrease in peak vertical GRF and increased trunk flexion angle and knee flexion displacement are factors that decrease ACL injury risk and loading and may be adaptation strategies to protect the knee when fatigued.

Comparison Between Unilateral and Bilateral Plyometric Training on Single and Double Leg Jumping Performance

The phenomenon of bilateral deficit in jumping implies that greater muscle power can be developed when performing maximal single leg jumps, compared with two-leg jumps. Thus, it may be hypothesized that training with single leg plyometric exercises would be more effective compared to an equivalent volume of double leg plyometric training. PURPOSE: To compare the effects of unilateral and bilateral plyometric training on single and double leg jumping performance. METHODS: Fifteen moderately trained subjects (age: 19.6±2.1 yrs, height: 172±9 cm, body mass: 65.6±10.6 kg) were randomly assigned to either a unilateral (U, n=7) or a bilateral group (B, n=8). Both groups performed maximal effort plyometric leg exercises two times per week for 6 weeks (6 exercises per session, 3 sets of 10 repetitions per exercise), as well as 3 sets of knee extensions and flexions at 70%-90% of their 1 repetition maximum. The U group performed all plyometric and knee flexion/extension exercises with both legs, while the B group performed half the repetitions with each leg, so that the total exercise volume was the same. Jumping performance was assessed by double and single leg countermovement jumps (CMJ) and drop jumps (DJ) from 30 cm, measured using an optical measurement system (Optojump). Reactive strength index (RSI) was calculated from DJ data (jump height and ground contact time). Results were analyzed using a 2 x 2 ANOVA with repeated measures in one factor and Tukey’s post-hoc test. RESULTS: CMJ with both legs significantly improved equally in the U and B groups by 12.1±7.2% and 11.0±5.5% (p<0.001), respectively. However, single-leg CMJ, quantified as the sum of dominant and non-dominant single leg CMJ, only improved in the U group (19.0±7.1%, p<0.001) and was unchanged in the B group (3.4±8.4%, p=0.80). Similarly, RSI for single leg only improved in the U group (from 0.95±0.21 to 1.17±0.25 m·s-1, p=0.002), but not in the B group. CONCLUSIONS: Plyometric training with single leg exercises was more effective in increasing both single and double-leg jumping performance, compared to bilateral training.

Collective concerted motion in a molecular adlayer visualized through the surface diffusion of isolated vacancies.

We have measured STM movies to study the diffusion of individual vacancies in a self-assembled layer of a tetrathiafulvalene derivative (exTTF) on Au(111) at room temperature. The diffusion is anisotropic, being faster along the compact direction of the molecular lattice. A detailed analysis of the anisotropic displacement distribution of the single vacancies shows that the relative abundance of double jumps (that is, the collective motion of molecular dimers) with respect to single jumps is rather large, the number of double jumps being more than 20% of the diffusion events. We conjecture that the relative abundances of long jumps might be related to the strength of the intermolecular bonding and the misfit of the molecular overlayer with the substrate lattice.

Fourier-cosine method for pricing forward starting options with stochastic volatility and jumps

ABSTRACTThis article provides an efficient method for pricing forward starting options under stochastic volatility model with double exponential jumps. The forward characteristic function of the log asset price is derived and thereby forward starting options are well evaluated by Fourier-cosine technique. Based on adaptive simulated annealing algorithm, the model is calibrated to obtain the estimated parameters. Numerical results show that the pricing method is accurate and fast. Double exponential jumps have pronounced impacts on long-term forward starting options prices. Stochastic volatility model with double exponential jumps fits forward implied volatility smile pretty well in contrast to stochastic volatility model.

American-style options in jump-diffusion models: estimation and evaluation

We propose dynamic programming coupled with finite elements for valuing American-style options under Gaussian and double exponential jumps à la Merton [J. Financ. Econ., 1976, 3, 125–144] and Kou [Manage. Sci., 2002, 48, 1086–1101], and we provide a proof of uniform convergence. Our numerical experiments confirm this convergence result and show the efficiency of the proposed methodology. We also address the estimation problem and report an empirical investigation based on Home Depot. Jump-diffusion models outperform their pure-diffusion counterparts.

Iterative algorithm for the first passage time distribution in a jump–diffusion model with regime-switching, and its applications

For a regime-switching model with a finite number of regimes and double phase-type jumps, Jiang and Pistorius (2008) derived matrix equations with real parameters for the Wiener–Hopf factorization. The Laplace transform of the first passage time distribution is expressed in terms of the solution of the matrix equations. In this paper we provide an iterative algorithm for solving the matrix equations of Jiang and Pistorius (2008) with complex parameters. This makes it possible to obtain numeric values of the Laplace transform with complex parameters for the first passage time distribution. The Laplace transform with complex parameters can be inverted by numerical inversion algorithms such as the Euler method. As an application, we compute the prices of defaultable bonds under a structural model with regime switching and double phase-type jumps.

College Tennis Players Demonstrate Asymmetry During Single-Leg &amp; Double-Leg Countermovement Jumps

Assessing bilateral asymmetry can help identify risk of injury in sport. More accurate assessments of risk can be acquired if sport-specific asymmetry is known. That is, some sports may evoke a certain asymmetry while others do not. PURPOSE: The purpose of this study was to determine whether or not bilateral asymmetry exists among NCAA Division I male tennis players performing single leg (SL CMJ) and double leg countermovement jumps (DL CMJ). A second purpose was to determine how often an asymmetry was present in the same leg during SL CMJ and DL CMJ. METHODS: Nine NCAA Division I male tennis players (20.5±1.5yr; 76.3±6.4kg) performed SL CMJ and DL CMJ on a force plate (1000Hz). Two SL CMJ were performed on each leg. Peak power was calculated using ground reaction force data. Asymmetry was then determined between the less and more powerful legs. Next, participants performed six DL CMJ. Two jumps were performed with both feet on the force plate and two jumps were performed with each foot on the force plate and the other foot off. This technique allowed for the assessment of bilateral asymmetry during DL CMJ and the relative contribution of each leg to the peak vertical force produced by both legs. Paired t-tests assessed the presence of bilateral asymmetry during SL CMJ and DL CMJ. Finally, we determined the frequency by which asymmetry existed on the same leg during SL CMJ and DL CMJ. RESULTS: During SL CMJ, there was an asymmetry of -3.1±3.0% between the less and more powerful legs (2381±286W vs. 2477±267W; p=.003). During DL CMJ, an asymmetry of -5.2±2.5% was observed between the weaker and stronger leg (879±73N vs. 926±62N; p<0.001), which accounted for relative contributions of 48.6±0.6% and 51.4±0.6% to the total double-leg effort, respectively. Remarkably, asymmetry occurred in the same leg during SL CMJ and DL CMJ in 8 out of 9 of the cases (89%). CONCLUSIONS: NCAA Division I men’s tennis players demonstrate asymmetry during SL CMJ and DL CMJ, and the asymmetry was present on the same side during SL CMJ and DL CMJ. These results can be used in future research, to determine the risk of injury when a tennis player has an asymmetry beyond the normal values observed in the sport. These results can also be used to guide rehabilitation and to make decisions about return to play after injury.

Asymptotic Analysis of Stock Price Densities and Implied Volatilities in Mixed Stochastic Models

In this paper, we obtain sharp asymptotic formulas with error estimates for the Mellin convolution of functions defined on $(0,\infty)$ and use these formulas to characterize the asymptotic behavior of marginal distribution densities of stock price processes in mixed stochastic models. Special examples of mixed models are jump-diffusion models and stochastic volatility models with jumps. We apply our general results to the Heston model with double exponential jumps and perform a detailed analysis of the asymptotic behavior of the stock price density, the call option pricing function, and the implied volatility in this model. We also obtain similar results for the Heston model with jumps distributed according to the normal inverse Gaussian law.

Method of teaching of the double jumps which paid attention to grip operation

Method of teaching of the double jumps which paid attention to grip operation