Peak Average Power Research Articles

Distributed SC-FDMA sub-carrier assignment for digital mobile satellite

Single carrier multiple access division (SC-FDMA) technology is one of the good uplink modulation techniques in a wireless communication system. Promises high transmission speed, low bit error rate and high spectral efficiency with low peak to average power ratio (PAPR) compared to OFDMA. This paper is proposed analytical model and link level simulation using MATLAB® to enhance the ratio of peak average power (PAPR) performance for distributed SC-FDMA sub-carrier assignment of. The methodology using the first full-featured digital MIMO software allows for in-depth verification and improvement of MIMO technologies applied to satellite broadcasting networks. Moreover, the demonstrator allows to complete and confirm our theory and simulation-based. The aim of this paper is to enhancement PAPR by analyzing the mobile satellite digital that employed distributed sub-carrier assignment for MIMO-SC-FDMA. The model is verified and validated by link level simulation.

Relationship between lower limb power and dynamic stability in volleball players

Abstract Introduction As in all team sports, lower limb power is an important quality of any player. Especially when it comes to volleyball, a game that relies on jumping performance on almost every action except reception. Another crucially important quality of the lower limbs is dynamic stability. Without the latter, the frequency of injuries rises, and that is something any coach or player wants to avoid. The question arises: Are the two qualities related? Aim The study aimed to investigate the correlation between lower limb power and force measured using an inertial flywheel training/measuring device and dynamic stability evaluated through the Y balance test. Material and method The Y balance test was used for evaluating the lower limb dynamic stability of 8 Romanian volleyball players. In addition, using an inertial flywheel training system (kBox 4 Pro, Exxentric, Sweden) and kMeter II measuring device the following parameters where measured: average force AvF (N), average power AvP (W), concentric peak power ConPP (W), eccentric peak power EccPP(W). The relative peak power RPP (W/kg) was calculated by dividing concentric peak power by the weight of the volleyball player. The subjects performed 8 maximal squats using the kBox harness and the L (0,05 kgm2) flywheel Results Composite reach distance (CRD) means for the lower limbs have been compared using the t-test and although there is a difference of 1.8%, it isn’t significant, (p<0,001). We have found a direct correlation between the average composite reach distance and relative peak power (r=0.71, p=0.045) and also with the average power (r=0.75, p=0.032) of the lower limbs. The composite reach distance for the right leg correlates with the relative peak power (r=0.73, p=0.036); average force (r=0.73, p=0.039), and average power (r=0.77, p=0.024). For the left leg, however, the only correlation found with the CRD is the average power (r=0.75, p=0.044). Conclusions The medium composite reach distance CRDM is directly correlated with the average lower limb power and relative peak power but due to the small sample size, the power of this effect is unknown. CRDR (right leg) significantly correlates with relative peak power, average power but also with average force whereas CRDL (left leg) only correlates with average power. This does not come as a surprise because all the subjects are right side dominant. There is no significant difference between CRDR and CRDL p<0.001. This is quite important because stability asymmetries of the lower limbs may lead to injury.

Pulsed Laser Performance of Erbium Doped Fiber Laser Using Titanium Dioxide Nanoparticles as Saturable Absorber

In this work, titanium dioxide TiO2 nanoparticles embedded in thin composite film was used as saturable absorber (SA) in erbium doped fiber (EDF) laser. The thin film was prepared by mixing TiO2 nanoparticles with polyvinyl alcohol (PVA) as host. Upon inserting the SA in a laser cavity, the output spectrum shifts to 1533.4 nm from 1563.8 nm. The laser performance was evaluated in the pump power range of 76 mW – 131 mW. The repetition rate of the mode-locked pulses was 989.0 kHz with a pulse width of 1.26 ps measured. The slope efficiency of the system is 8.58%. Maximum average power and peak power generated from the laser is 11.69 mW and 9.41 kW, respectively. This work explored the potential of TiO2-PVA thin film as saturable absorber for 1.5 μm laser system.

Precoder Design for Communication-Efficient Distributed MIMO Receivers With Controlled Peak-Average Power Ratio

We consider the problem of communicating over a relay-assisted multiple-input multiple-output (MIMO) channel with additive noise, in which physically separated relays forward quantized information to a central decoder where the transmitted message is to be decoded. We assume that channel state information is available in the transmitter and show that the design of a rational-forcing precoder - a precoder which is matched to the quantizers used in the relays - is beneficial for reducing the symbol error probability. It turns out that for such rational-forcing precoder based systems, there is natural tradeoff between the peak to average power ratio in the transmitter and the rate of communication between the relays and the central decoder. The precoder design problem is formulated mathematically, and several algorithms are developed for realizing this tradeoff. Optimality of the decoder communication rate is shown based on a result in distributed function computation. Numerical and simulation results show that a useful tradeoff can be obtained between the excess decoder communication rate and the peak-average power ratio in the transmitter.

Delay Aware Resource Allocation With Radio Remote Head Cooperation in User-Centric C-RAN

High spectral efficiency and low latency are required to provide ubiquitous communication for the emerging applications in 5G wireless communication networks. In this letter, we propose a novel framework that considers these requirements simultaneously by integrating the notion of effective capacity (EC) into orthogonal frequency division multiple access (OFDMA) cloud-radio access networks (C-RAN) where the users select the distributed radio remote heads (RRHs) based on their specific delay requirements to transmit over different subcarriers cooperatively. Consequently, an optimization problem is defined to maximize the EC under the average peak power constraint and the delay requirements. The problem is combinatorial and non-convex and an algorithm based on the duality and alternating optimization algorithms is proposed, which is efficiently computed with good accuracy. Simulation and analytical results demonstrate that the proposed solution has a near-optimal performance and there is a trade-off between delay and spectral efficiency. Moreover, the cooperation between RRHs can considerably improve the system throughput.

Effect of Acupuncture on the Timeliness of Explosive Forces Generated by the Male Shoulder Joint.

Athletes aim to improve muscle strength to optimize sports performance and gain a competitive edge. Although modern sports medicine includes rehabilitation treatment methods for improving the explosive force of athletes, including acupuncture, a common alternative therapy, research on the effectiveness of acupuncture in improving the timeliness of explosive forces is limited. There is uncertainty regarding how long the effects of acupuncture treatment persist after treatment. Therefore, the purpose of this study was to explore the effect of acupuncture on the timeliness of explosive forces generated by the male shoulder joint. Eighteen healthy men underwent tests of shoulder adduction/abduction (Add/Abd) and flexion/extension (Flex/Ext) through an isokinetic measurement system. Acupuncture was used to stimulate LU1 (Zhongfu), LU3 (Tianfu), LU4 (Xiabai), LI14 (Binao), SJ13 (Naohui), SJ14 (Jianliao), and SJ12 (Xiaoluo), and the isokinetic parameters were recorded before and after acupuncture. After acupuncture, isokinetic muscle force parameters including the maximum (Max) torque, the average power, the average peak power, the average work, and the total work increased significantly (P < 0.05), whereas the average max torque Abd/Flex did not. Additionally, the preintervention values of the shoulder joints for Add/Abd and Flex/Ext were significantly greater than those at post 1 and post 2 (P < 0.05). The isokinetic results suggest that acupuncture can increase the explosive force of the male shoulder joint Add/Abd and Flex/Ext. Muscle cannot be fully activated when calcium saturation is below the maximal level. In this case, the postactivation potentiation (PAP) may enhance voluntary muscle force production. The effect of acupuncture is time-dependent, that is, the effects of acupuncture gradually weaken and disappear by approximately 10 minutes after acupuncture. Therefore, we suggest that acupuncture is used as an alternative therapy in sports competitions to increase the explosive forces of the shoulder joint, thereby improving sports performance.

Design of low-power and high-speed CNTFET-based TCAM cell for future generation networks

In network routers and lookup tables for fast searching, ternary content addressable memories (TCAMs) have found great use. For future generation networks, architecture is essential for efficient TCAM in terms of power consumption and speed of service. A TCAM cell with an optimized CNTFET is proposed in this paper. The TCAM cell proposed is designed for improved performance using optimized CNTFET with shorted gate (SG) CNTFET and independent gate CNTFET (IG-CNTFET). As access transistors, IG-CNTFETs are used in the SRAM cell design, and SG-CNTFETs are used in the comparison circuit. The 4 × 4 TCAM array was also planned using the TCAM cells proposed. The suggested CNTFET TCAM cell and array showed better performance than that of TCAM cells and arrays based on CMOS and FinFET. The suggested CNTFET-based TCAM with SG shows a substantial improvement in search delay and average power and peak power compared to CMOS and FinFET-based cell technology. Compared to CMOS and FinFET technologies, the average capacity of the proposed TCAM cell is substantially enhanced. The proposed technique's search delay is enhanced by 17.2 percent over TCAM cell based on FinFET. Compared to the FinFET and CMOS-based TCAM cell, the peak power of the proposed technique is also enhanced. All the simulations are carried out at 32 nm with HSPICE technology.

Impact of the Lockdown during the COVID-19 Pandemic on Electricity Use by Residential Users

The COVID-19 pandemic and the associated lockdown can be regarded as a forced social experiment, the results of which show how to use energy under specific conditions. During this period, there was a reduction in electricity consumption at the level of the power system, but a different specificity distinguishes the group of household users. The article aims at presenting and analysing the identified issues concerning residential electricity users based on the experience from the COVID-19 pandemic lockdown. Data from energy meters from almost 7000 flats in Warsaw’s housing estates during the lockdown in 2020 and the analogous period before the pandemic were used. The analysis showed that, on average, residential users staying practically the whole day in their flats increased their energy consumption, but without increasing their average daily peak power, smoothing the profile in the morning hours to the level reaching the peak power that had occurred in the analogous period before the lockdown. The peak power of the sections feeding the different numbers of dwellings also remained practically unchanged during the lockdown compared to the pre-pandemic period. The pressure to work and educate remotely should contribute to an increase in the digital competence of society, which may result in an increased interest in new forms of activity and cooperation based on demand-side response and prosumption mechanisms, with digital settlements for energy exchange and services.

Optimizing Electrodeposited Manganese Oxide at Carbon Cloth Electrodes for Harvesting Salinity-Gradient Energy

Electrical power can be generated from the controlled mixing of salinity gradients when solutions of differing salt concentration bathe opposing electrodes in a flow-cell configuration. The power density of such salinity-gradient cells is enhanced by moving beyond the double-layer capacitance of high-surface-area carbons to electrode materials that store charge via pseudocapacitance (e.g., manganese oxides; MnOx). We investigate the effects of MnOx loading on salinity-gradient power production, using anodic electrodeposition to coat carbon cloth (CC) electrodes with nanostructured Akhtenskite-type MnOx at controlled incremental mass loadings. Uniform MnOx deposition at exposed CC surfaces is confirmed by scanning electron microscopy with elemental mapping. Power-density measurements with the resulting MnOx@CC electrodes in a salinity-gradient cell fed by low (0.02 M NaCl) and high (0.5 M NaCl) concentration solutions show a positive correlation with MnOx loading, reaching a competitive peak average power density of 0.221 ± 0.001 mW cm–2 at 1.90 mg cm–2 MnOx. By comparing flow-cell data with results from half-cell electroanalytical characterization of individual electrodes, we show that salinity-gradient performance is ultimately limited by resistive losses in the modestly conductive MnOx coating at higher mass loading/thickness.

The effects of phosphocreatine disodium salts plus blueberry extract supplementation on muscular strength, power, and endurance

BackgroundNumerous studies have demonstrated the efficacy of creatine supplementation for improvements in exercise performance. Few studies, however, have examined the effects of phosphocreatine supplementation on exercise performance. Furthermore, while polyphenols have antioxidant and anti-inflammatory properties, little is known regarding the influence of polyphenol supplementation on muscular strength, power, and endurance. Thus, the purpose of the present study was to compare the effects of 28 days of supplementation with phosphocreatine disodium salts plus blueberry extract (PCDSB), creatine monohydrate (CM), and placebo on measures of muscular strength, power, and endurance.MethodsThirty-three men were randomly assigned to consume either PCDSB, CM, or placebo for 28 days. Peak torque (PT), average power (AP), and percent decline for peak torque (PT%) and average power (AP%) were assessed from a fatigue test consisting of 50 maximal, unilateral, isokinetic leg extensions at 180°·s− 1 before and after the 28 days of supplementation. Individual responses were assessed to examine the proportion of subjects that exceeded a minimal important difference (MID).ResultsThe results demonstrated significant (p < 0.05) improvements in PT for the PCDSB and CM groups from pre- (99.90 ± 22.47 N·m and 99.95 ± 22.50 N·m, respectively) to post-supplementation (119.22 ± 29.87 N·m and 111.97 ± 24.50 N·m, respectively), but no significant (p = 0.112) change for the placebo group. The PCDSB and CM groups also exhibited significant improvements in AP from pre- (140.18 ± 32.08 W and 143.42 ± 33.84 W, respectively) to post-supplementation (170.12 ± 42.68 W and 159.78 ± 31.20 W, respectively), but no significant (p = 0.279) change for the placebo group. A significantly (p < 0.05) greater proportion of subjects in the PCDSB group exceeded the MID for PT compared to the placebo group, but there were no significant (p > 0.05) differences in the proportion of subjects exceeding the MID between the CM and placebo groups or between the CM and PCDSB groups.ConclusionsThese findings indicated that for the group mean responses, 28 days of supplementation with both PCDSB and CM resulted in increases in PT and AP. The PCDSB, however, may have an advantage over CM when compared to the placebo group for the proportion of individuals that respond favorably to supplementation with meaningful increases in muscular strength.

The effects of plyometric training and β-alanine supplementation on anaerobic power and serum level of carnosine in handball players

Plyometric training and β-alanine supplementation are common among athletes, although its mixed-use had never been investigated in handball players. Thus, a randomized, double-blind, placebo-controlled trial was performed to investigate the impacts of a plyometric training regimen with or without β-alanine supplementation on anaerobic performance and carnosine levels in male handball players. Eighteen male handball players were allocated to either a plyometric training group receiving placebo (placebo, n = 9; 24.33 ± 5.12 years) and a plyometric training group receiving β-alanine (β-alanine, n = 9; 18.89 ± 2.14 years) supplementation. Participants were evaluated for anaerobic power, serum level of carnosine, and blood lactate before and after a 4-week intervention. Average power and peak power were increased more after β-alanine ingestion than after placebo (10.4 and 9.1% versus − 1.7 and − 6.8%, respectively). Fatigue index was significantly decreased by 26.2% in the placebo group, with no significant change in the β-alanine group (+ 10.6%). The serum level of carnosine in both groups was significantly increased compared with pre-intervention. It was increased more after β-alanine supplementation than placebo (61.8 versus 43.6%). It was concluded that β-alanine consumption during plyometric training might add further adaptive changes related to anaerobic power and carnosine levels.

MIMO Dual-Functional Radar-Communication Waveform Design With Peak Average Power Ratio Constraint

In this paper, novel Dual-Functional Radar-Communication (DFRC) waveforms with peak average power ratio (PAPR) constraint are designed, which are under the multiple-input multiple-output (MIMO) radar-communication system. The DFRC waveforms transmitted by multiple antennas can send communication information to many downlink cellular users and detect radar targets simultaneously. An optimization model is established to minimize the downlink multi-user interference (MUI) under PAPR constraint. The model is non-convex quadratically constrained quadratic programs (QCQP) and can be derived into a convex problem and solved by using the semi-definite relaxation (SDR) technique with rank-one approximation. Numerical simulations demonstrate that our proposed waveforms can achieve a better radar performance in practical scenarios without sacrificing the communication performance.

The Energy, Momentum, and Peak Power Radiated by Negative Lightning Return Strokes

Electromagnetic radiation fields generated by return strokes transport both energy and momentum from the return stroke to outer space. The momentum transported by the radiation field has only a vertical or z component due to azimuthal symmetry (cylindrical symmetry) associated with a vertical return stroke. In this paper, the energy, momentum, and peak power radiated by return strokes as a function of the return stroke current, return stroke speed, and the zero-crossing time of the radiation fields are studied. The results obtained by numerical simulations for the energy, vertical momentum, and the peak power radiated by lightning return strokes (all parameters normalized by dividing them by the square of the radiation field peak at 100 km) are the following: A typical first return stroke generating a radiation field having a 50 μs zero-crossing time will dissipate field normalized energy of about (1.7–2.5) × 103 J/(V/m)2 and field-normalized vertical momentum of approximately (2.3–3.1) × 10−6 Kg m/s/(V/m)2. A radiation field with a zero-crossing time of 70 μs will dissipate about (2.6–3.4) × 103 J/(V/m)2 in field-normalized energy and (3.2–4.3) × 10−6 Kg m/s/(V/m)2 in field-normalized vertical momentum. The results show that, for a given peak radiation field, the radiated energy and momentum increase with increasing zero-crossing time of the radiation field. The normalized peak power generated by a first return stroke radiation field is about 1.2 × 108 W/(V/m)2 and the peak power is generated within about 5–6 μs from the beginning of the return stroke. Conversely, a typical subsequent return stroke generating a radiation field having a 40 μs zero-crossing time will dissipate field-normalized energy of about (6–9) × 102 J/(V/m)2 and field-normalized vertical momentum of approximately (7.5–11) × 10−7 Kg m/s/(V/m)2. The field-normalized peak power generated by a subsequent return stroke radiation field is about 1.26 × 108 W/(V/m)2 and the peak power is generated within about 0.7–0.8 μs from the beginning of the return stroke. In addition to these parameters, the possible upper bounds for the energy and momentum radiated by return strokes are also presented.

A Preliminary Examination of Shoulder Joint Function Following Shoulder Complex Training and In-Season Play in Youth Baseball Players

Background: As shoulder care continues to be a concern for youth baseball players, coaches, parents, researchers and clinicians, shoulder complex care should remain a point of emphasis especially for in overhead athletes. The impact of throwing volume and shoulder care is important for us to understand. Objective: The purpose was to examine the changes in shoulder complex function during a playing season combined with shoulder complex training in young male baseball players. Methods: Eleven male baseball players (11-15 y/o) served as subjects. Pre-testing included shoulder joint internal/external rotation peak torque and average work as measured with isokinetic dynamometry (Biodex System 4Pro). Training over the 18-week project duration was Crossover Symmetry “Activation” and “Strength” protocols completed per manufacturer recommendations. Adherence was tracked via a weekly email sent to the subject’s guardian to self-report completed training. Post-testing was conducted at the conclusion of the 18th week. Paired sample t-tests compared pre-test and post-test mean differences for peak torque and average power (p&lt;0.05). Results: All-subject average for training was 54 sessions over the 18 weeks. Estimated number of throws completed during practice and games over the 18 weeks was 8,400. For both testing speeds and for both internal and external shoulder joint rotation, peak torque increases ranged from ~50% for external rotation at 60 deg/s up to ~200% for internal rotation at 120 deg/s. Statistical differences (p&lt;0.001) were noted between all pre-test and post-test internal and external rotation peak torque values. For both testing speeds and for both internal and external shoulder joint rotation, average power increases ranged from ~38% at 60 deg/s for external rotation up to ~200% at 120 deg/s for internal rotation. Statistical differences (p&lt;0.005) were noted between all pre-test and post-test internal and external rotation average power values. Conclusions: Substantial increases in shoulder joint rotation peak torques and power were seen across the 18-week study duration. As this was a preliminary investigation, we have yet to discern if these increases are due to the shoulder complex training or volume of throwing that was completed.

UFMC and f-OFDM: Contender Waveforms of 5G Wireless Communication System

Because of the increased demand for high data rates, looking for using new technologies that meet these requirements are considered a necessary. Hence, Fifth Generation (5G) is expected to be impressive in offering these requirements and implement around 2020. Orthogonal Frequency Division Multiplexing (OFDM) is considered a main technology of LTE wireless communication standards. Due to its suffering from high Bit Error Rate (BER) and Peak Average Power Ratio (PAPR), OFDM doesn't consider as charming solution for future wireless communications and several emerging applications of 5G. Moreover, high Out of Band Emission (OOBE) and inability of supporting the flexible numerology are other demerits of OFDM systems. Thus, looking for alternative waveforms which have the ability of solving OFDM disadvantages are necessary to introduce it as contender candidate for 5G wireless communication systems. In this paper, both of Filtered-OFDM (f-OFDM) and Universal Filtered Multi carrier (UFMC) systems have been discussed for 5G wireless communication systems and compared to OFDM system. The results showed that f-OFDM system is better than both OFDM and UFMC systems and could be introducing as competitive candidate for 5G wireless communication systems because of its ability of reducing OOBE and enhancing BER performance.

Comprehensive Analysis of PAPR Reduction in OFDM, UFMC and Signal Scrambling UFMC Technique using Shuffled Frog Leaping Algorithm

Universal Filter Multi-Carrier (UFMC) is one of the most recommended waveform designs for the next-generation wireless communication system. UFMC provides high spectral efficiency, better sub-carrier separation with less PAPR when compared to OFDM. The major drawback of UFMC is that it suffers from a significant peak to average power ratio similar to multi-carrier communication techniques like Orthogonal Frequency Division Multiplexing (OFDM). The research gap is addressed by proposing the signal scrambling technique to reduce the Peak Average Power Ratio(PAPR) in UFMC. A Shuffled Frog Leaping Algorithm (SFLA) is used as an optimizer to verify the entire search space for optimal phase vectors within the time constraints to produce the best-modified UFMC signal with less PAPR. An analogy between OFDM, UFMC and signal-scrambling UFMC is performed, and it is observed that the signal-scrambled UFMC produces better results than general UFMC and OFDM in terms of PAPR.

Highly scalable multicycle THz production with a homemade periodically poled macrocrystal

The THz regime is widely appealing across many disciplines including solid-state physics, life sciences, and increasingly in particle acceleration. Multicycle THz pulses are typically formed via optical rectification in periodically poled crystals. However the manufacturing procedures of these crystals limit their apertures to below ~1 cm, which from damage limitations of the crystal, limits the total pump power which can be employed, and ultimately, the total THz power which can be produced. Here we report on the simple in-house fabrication of a periodically poled crystal using ~300 μm thick wafers. Each wafer is consecutively rotated by 180∘ to support quasi-phase matching. We validate the concept with a Joule-class laser system operating at 10 Hz and measure up to 1.3 mJ of energy at 160 GHz, corresponding to an average peak power of approximately 35 MW and a conversion efficiency of 0.14%. In addition, a redshifting of the pump spectrum of ~50 nm is measured. Our results indicate that high-power THz radiation can be produced with existing and future high-power lasers in a scalable way, setting a course toward multi-gigawatt multicycle THz pulses.

A 100Gbps all‐optical orthogonal frequency division multiplexing based on discrete Haar wavelet transform for radio over fiber system

AbstractAll‐optical orthogonal frequency division multiplexing (OOFDM) for a radio over fiber system (RoF) using discrete Haar wavelet transform (DHWT) is proposed and investigated for 100Gbps system. The system makes use of passive optical couplers to generate orthogonal symbols based on DHWT. Phase preemphasis technique is incorporated to minimize high peak average power ratio, which in turn minimizes the nonlinear effects of the system. Simulation set up of 25 × 4Gbps all‐optical OFDM is compared with that of the existing systems. Results of the proposed system are on a par with that of the conventional OFDM‐RoF systems employing discrete fourier transform.

Peak Average Power Reduction in NOMA by using PTSCT Technique

Background: High peak power is one of the several disadvantages which need to be addressed for its effective regularization. It hampers the performance of the system due to the utilization of the orthogonal frequency division multiplexing transmission scheme at the sender of the Non-orthogonal multiple access system. Objective: In this work, a new Partial transmission sequence circular transformation reduction technique is designed for Non-orthogonal multiple access schemes. Methods: Partial transmission sequence is considered to be one of the most efficient techniques to reduce the Peak to average power ratio but it leads to high computational complexity. Additionally, a circular transformation is implemented. In the proposed technique, circular transformation and alternate optimization are used. Results: Simulation results reveal that the Peak to average power ratio performance of the proposed technique is better as compared to the conventional partial transmission sequence. Conclusion: It is observed that the proposed technique achieved 80% Peak to average power ratio reduction and 90 % bit error rate performance as compared to the conventional Partial transmission sequence.

Repeated Application of a Novel Creatine Cream Improves Muscular Peak and Average Power in Male Subjects.

Whinton, AK, Donahoe, K, Gao, R, Thompson, KMA, Aubry, R, Saunders, TJ, Johnston, A, Chilibeck, PD, and Burr, JF. Repeated application of a novel creatine cream improves muscular peak and average power in male subjects. J Strength Cond Res 34(9): 2482-2491, 2020-Using a multicenter, randomized controlled trial, (N = 123, age 23 ± 4 years) we sought to determine whether administration of a novel, topical creatine supplement could improve muscular performance after acute and repeated (7-day) exposure. To study the acute performance enhancing effects of the supplement, subjects completed 5 sets of 15 maximal concentric single-leg knee extensions with and without the application of a low- (low dose [LD]-3.5 ml) or high-dose (high dose [HD]-7 ml) topical creatine cream. After a wash-out period, subjects had one leg randomized to receive either the creatine or placebo cream, with further randomization into an oral creatine or placebo supplement group. Subjects completed 5 sets of 15 maximal concentric single leg knee extensions before and after the supplementation protocol. After acute application, no significant differences in peak power (LD: 252 ± 93 W, HD: 261 ± 100 W, p = 0.21), average power (LD: 172 ± 65 W, HD: 177 ± 69 W, p = 0.78), or fatigue index (LD: 13.4 ± 10.6%, HD: 14 ± 11.9%, p = 0.79) were observed between experimental and placebo creams (peak power: LD: 244 ± 76 W, HD: 267 ± 109 W; average power: LD: 168 ± 57 W, HD: 177 ± 67 W; fatigue index: LD: 12.4 ± 9.6%, HD: 12.8 ± 10.6%) or when controlling for sex. After the 7-day supplementation protocol, a significant increase in average power (creatine: 203 ± 61-220 ± 65 W, placebo: 224 ± 61-214 ± 61 W) and peak power (creatine: 264 ± 73-281 ± 80 W, placebo: 286 ± 79-271 ± 73 W) in the leg receiving creatine cream was observed in male subjects. No differences were observed in female subjects. The topical creatine cream did not enhance measures of muscle performance after acute application, but was able to improve peak and average power in male subjects after 7 consecutive days of application.