Are Young Female Basketball Players Adequately Prepared for a Force-Velocity Jumping and Sprinting Assessment?

PURPOSE: The aim of this study was to explore the interday reliability of mechanical variables obtained from the horizontal and vertical force-velocity (FV) profiles in adolescent female basketball players. If found to be reliable, the associations between FV parameters (theoretical maximal force, velocity, and power), squat jump (SJ) height, 30-m sprint, and change of direction (COD) times were evaluated. METHODS: After familiarization, SJ against incremental loads, 30-m sprint, and 505-COD tests were obtained twice in 36 adolescent female basketball players (age = 15.4 [1.2] y). RESULTS: Reliability for vertical FV parameters was unacceptable, whereas 505-COD times and FV horizontal parameters (except for theoretical maximal power) showed a moderate to high reliability. 505-COD time was correlated with FV horizontal parameters (range: r = -.821, -.451), and a large association was observed with both SJ height (r = -.678, -.600) and 30-m sprint time (r = .813, .858). CONCLUSIONS: Due to low levels of strength, our athletes were not adequately prepared to obtain a reliable vertical FV profile. Practitioners can expect acceptable reliability of the horizontal FV profile. Given the association between COD performance and SJ height and 30-m sprint time, we encouraged practitioners with limited equipment at their disposal to use COD and/or 30-m sprint tests.

Variability in the Relationship Between Velocity Loss and Percentage of Completed Repetitions During Horizontal Leg Press and Bench Press in Postmenopausal Women.

ABSTRACT: Iglesias-Soler, E, Rial-Vázquez, J, Nine, I, Fariñas, J, Revuelta-Lera, B, and García-Ramos, A. Variability in the relationship between velocity loss and percentage of completed repetitions during horizontal leg press and bench press in postmenopausal women. J Strength Cond Res XX(X): 000-000, 2024-This study aimed to analyze the intersubject variability in the relationship between percentage of velocity loss (%VL) and percentage of repetitions performed out of maximum possible (%MNR) in postmenopausal women. Thirty-five postmenopausal active women (58 ± 3 years) performed sets leading to muscular failure, completing 10-13 repetitions, in both leg press (LP) and bench press (BP). Mean lift velocity of each repetition was expressed as a percentage of the fastest repetition, and repetitions were quantified as a percentage of the maximum number of repetitions completed in the set. Given the hierarchical structure of the data, %VL-%MNR relationships were fitted by linear mixed model regressions. A significant intersubject variability in the intercept (i.e., %MNR associated with 0%VL) was detected (p < 0.001 in both LP and BP), even when centered values of the completed repetitions were included in the models. The estimated variance in the intercept for LP (117.39; SE: 45.41) was almost double that for BP (67.47; SE: 20.27). The variability observed in the intercept entailed variability in the estimated %MNR for specific %VL values. The use of velocity loss thresholds for estimating the intensity of effort in active postmenopausal women does not overcome uncertainty of more traditional methods.

Cross education is modulated by set configuration in knee extension exercise.

OBJECTIVES: The main aim of this study was to determine the effects of set configuration during five weeks of unilateral knee extension resistance training on untrained knee extensors performance. METHODS: Thirty-five subjects were randomly assigned to traditional training (TTG; n=14), rest-redistribution (RRG; n=10) and control group (CON; n=11). TTG and RRG groups trained the dominant knee extensors twice a week with the 10-repetition maximum (RM) load. TTG performed four sets of eight repetitions with three min-rest between sets and RRG 32 repetitions with 17.4 seconds of rest between each one. Before and after interventions, anthropometry, muscle thickness (MT), pennation angle (PA), 1RM, number of repetitions with 10RM pretest load (N10RM), maximum propulsive power (MPP) and maximum voluntary isometric contraction (MVIC) were measured. RESULTS: 1RM of the untrained leg increased only in the TTG group (p<0.001, 10.3% compared with Pre-test). 1RM, MPP and N10RM increased in the trained leg in both TTG (p<0.001) and RRG (p<0.001). No changes occurred in MT or PA. CONCLUSIONS: These results suggest that, when it is not possible to perform bilateral exercises (e.g., leg injury), traditional set configurations should be recommended to improve maximal voluntary force in the untrained leg.

Face Masks at the Gymnasium: Physiological Responses and Mechanical Performance Are Not Compromised by Wearing Surgical or Filtering Facepiece 2 Masks in Healthy Subjects.

ABSTRACT: Rial-Vázquez, J, Nine, I, Guerrero-Moreno, JM, Rúa-Alonso, M, Fariñas, J, Márquez, G, Giráldez-García, MA, Méndez-Bouza, KY, López-Pillado, H, Coutado-Sánchez, E, Losada-Rodríguez, A, and Iglesias-Soler, E. Face masks at the gym: physiological responses and mechanical performance are not compromised by wearing surgical or filtering facepiece 2 masks in healthy subjects. J Strength Cond Res 37(7): 1404-1410, 2023-This study explored the effects of wearing 2 types of face masks on mechanical performance and physiological responses during high-intensity resistance exercise. Twelve healthy men performed 3 workout protocols in a randomized order: wearing a surgical or filtering facepiece 2 (FFP2) mask or without a mask. Each workout consisted of 3 sets of 10 repetitions of bench press (BP) and parallel squat (SQ) with a 12 repetition maximum load, including 2 minutes of recovery between sets and exercises. Mechanical performance was evaluated through the mean propulsive velocity and the number of repetitions completed during each session. Physiological responses were the oxygen saturation (SpO2), blood lactate concentration, heart rate (HR), and HR variability. Perceived exertion was recorded after each set, and The Beck Anxiety Inventory scale was completed at the end of each workout. The number of repetitions completed and the session mean propulsive velocity {(BP [m·s-1]: surgical: 0.35 ± 0.05; FFP2: 0.36 ± 0.04; nonmask: 0.38 ± 0.06) and (SQ: surgical: 0.43 ± 0.05; FFP2: 0.40 ± 0.07; nonmask: 0.41 ± 0.05)} were similar between conditions (p > 0.05). Heart rate recorded during sessions was similar across conditions: surgical: 119 ± 14, FFP2: 117 ± 13, and nonmask: 118 ± 10 bpm (p = 0.919). Face masks had no effect on SpO2, blood lactate concentration, HR variability, perceived exertion, and anxiety values (p > 0.05). Face masks do not compromise strength performance, physiological parameters, and perceived comfort of young and healthy individuals during a high-intensity resistance training session.

Hemodynamic Response During Different Set Configurations of a Moderate-load Resistance Exercise.

We aimed to determine the cardiovascular responses to two different set configuration resistance-exercise protocols during a knee extension composed of 40 repetitions with a 15RM load and a total resting time of 360 seconds. Twenty-four healthy sport science students randomly performed two sessions: (a) a long set configuration (LSC: 4 sets of 10 repetitions with 2 min rest between sets), and (b) a short set configuration (SSC: 8 sets of 5 repetitions with 51 s rest between sets). Before and during exercise, peak and mean values of heart rate, blood pressure, rate pressure product, and pulse pressure were obtained. Results showed that both protocols increased the overall peak and mean blood pressure values (p<0.001). However, LSC entailed a higher peak blood pressure response at the last set (p=0.041) and an increase throughout the first 30 repetitions (p≤0.007), whereas SSC kept steady after the first 20 repetitions. Additionally, LSC caused higher overall peak and mean heart rate and rate pressure product values (p≤0.003). Summarily, although both protocols raised blood pressure, SSC reduced the extent of the pressure and chronotropic response during resistance exercise.

Training load but not fatigue affects cross-education of maximal voluntary force.

The purpose of this study was to determine the effects of training load (25% vs. 75% of one repetition maximum [1RM]) and fatigue (failure vs. non-failure) during four weeks of unilateral knee extension resistance training (RT) on maximal voluntary force in the trained and the untrained knee extensors. Healthy young adults (n = 42) were randomly assigned to control (CON, n = 9, 24 ± 4.3 years), low-load RT to failure (LLF, n = 11, 21 ± 1.3 years, three sets to failure at 25% of 1RM), high-load RT to failure (HLF, n = 11, 21 ± 1.4 years, three sets to failure at 75% of 1RM), and high-load RT without failure (HLNF, n = 11, 22 ± 1.5 years, six sets of five repetitions at 75% of 1RM) groups. Before and after the four weeks of training, 1RM, maximal voluntary isometric force, and corticospinal excitability (CSE) were measured. 1RM in the trained (20%, d = 0.70, 15%, d = 0.61) and the untrained knee extensors (5%, d = 0.27, 6%, d = 0.26) increased only in the HLF and HLNF groups, respectively. MVIC force increased only in the trained leg of the HLF (5%, d = 0.35) and HLNF groups (12%, d = 0.67). CSE decreased in the VL of both legs in the HLNF group (-19%, d = 0.44) and no changes occurred in the RF. In conclusion, high- but not low-load RT improves maximal voluntary force in the trained and the untrained knee extensors and fatigue did not further enhance these adaptations. Voluntary force improvements were unrelated to CSE changes in both legs.

Load-velocity Profiles Change after Training Programs with Different Set Configurations.

This study explored the changes in load-velocity relationship of bench press and parallel squat exercises following two programs differing in the set configuration. A randomized controlled trial was carried out in a sample of 39 physically active individuals. Participants were assigned to rest redistribution set configuration, traditional set configuration, or control groups. Over 5 weeks, the experimental groups completed 10 sessions with the 10 repetitions maximum load of both exercises. Rest redistribution sets consisted in 16 sets of 2 repetitions with 60 s of rest between sets, and 5 min between exercises, whereas traditional sets entailed 4 sets of 8 repetitions with 5 min of rest between sets and exercises. The load-velocity relationships of both exercises were obtained before and after the training period. For bench press, an increase of the velocity axis intercept, and a decrease of the slope at post-test were observed in both rest redistribution (p<0.001, G=1.264; p<0.001; G=0.997) and traditional set (p=0.01, G=0.654; p=0.001; G=0.593) groups. For squat, the slope decreased (p<0.001; G=0.588) and the velocity axis intercept increased (p<0.001; G=0.727) only in the rest redistribution group. These results show that rest redistribution sets were particularly efficient for inducing changes in the load-velocity relationship.

Set Configuration in Strength Training Programs Modulates the Cross Education Phenomenon.

ABSTRACT: Fariñas, J, Mayo, X, Giraldez-García, MA, Carballeira, E, Fernandez-Del-Olmo, M, Rial-Vazquez, J, Kingsley, JD, and Iglesias-Soler, E. Set configuration in strength training programs modulates the cross education phenomenon. J Strength Cond Res 35(9): 2414-2420, 2021-This study aimed to compare the strength gains in the nontrained arm after 2 independent unilateral training programs differing in the set configuration. Thirty-five subjects were randomly assigned to 3 groups: traditional training (TT; n = 12), cluster training (CT; n = 11), or control (CON; n = 12). The experimental groups performed a 5-week training program of a unilateral biceps curl exercise with the dominant limb using the 10 repetition maximum (10RM) load. Traditional training performed 5 sets of 6 repetitions and 135 seconds of rest between sets. Cluster training completed 30 repetitions with 18.5 seconds of rest between each repetition. Anthropometry (ANT), muscle thickness (MT), 1RM, the number of repetitions with 10RM (n10RM), and isometric maximal voluntary contraction (MVC) were measured before and after the intervention. Regarding the nontrained arm, TT improved 1RM (7.3%, p < 0.001). No changes were observed in CT. Regarding the trained arm, TT improved 1RM (9.1%, p < 0.001), n10RM (p = 0.005), and MVC (p = 0.011), whereas CT only showed a trend for improvement of 1RM (3.4%, p = 0.052). These results suggest that when total volume and repetition-to-rest ratio are equated, a more fatiguing set configuration causes a higher effect on the non-trained limb.

Effects of bilateral and non-dominant practices on the lateral preference in judo matches.

This study analysed the effects of bilateral and non-dominant practice on novice practitioners' lateral preference for judo skills in a combat context (i.e., randori). Thirty sports sciences students (22 men and 8 women; mean age 19 ± 1 years) with right hand, foot, and counterclockwise rotation preferences were divided into 3 groups: bilateral (BG; n = 8), non-dominant (NDG; n = 11), and control (CG; n = 11). Participants received 8 weeks of training at a rate of 3 days per week. The NDG was trained to perform judo skills exclusive with their non-dominant side, while the BG performed every task symmetrically. Before and after training, participants were recorded during two 3-min randoris to obtain the percentage of their engagement in dominant side actions. Pretest percentages were 73.1 ± 19.9%, 77.8 ± 18.8%, and 68.9 ± 27.2% for BG, NDG, and CG, respectively. Post-test values were 75.0 ± 15.6%, 23.3 ± 27.9%, and 72.2.9 ± 20.4%, respectively. Significant differences were observed between NDG and each of the other groups after the training. Changes from pretest were only significant for NDG (P = 0.003). These results suggest that lateral preference among novice judo practitioners during randori can be modulated by the type of practice.

Changes in the Force-Velocity Mechanical Profile After Short Resistance Training Programs Differing in Set Configurations.

The main aim of this study was to analyze the effect of resistance training programs differing in set configuration on mechanical force-velocity profiles. Thirteen participants performed 10 unilateral knee extension training sessions over 5 weeks. Each limb was randomized to one of the following set configurations: traditional (4 sets of 8 repetitions at maximum intended velocity, 10RM load, 3-min pause between sets) or interrepetition rest (32 maximum intended velocity repetitions, 10RM load, 17.4 s of rest between each repetition). Velocity of each repetition was recorded throughout the program. Before and after training, individual linear force velocities were calculated, and the following parameters were obtained: force and velocity axis intercept, slope, and estimated maximum power. Mean velocity was higher throughout the program for interrepetition rest configuration (0.54 ± 0.01 vs. 0.48 ± 0.01 m∙s-1 for interrepetition rest, and traditional configuration respectively; main effect of set configuration: P < .001). There was a significant increase in force and velocity intercepts, but a steeper negative slope after both training protocols (main effect of time: P < .001 for every variable). Differences in resistance training velocity did not affect the adaptations. Our results suggest that, in a short-term program, maximum intended rather than actual velocity is a key factor to modulate strength adaptations.

Inter-repetition rest training and traditional set configuration produce similar strength gains without cortical adaptations.

This study compared the functional and neural effects of two strength training programmes differing in set configuration. Thirteen participants performed 10 sessions, over a period of 5 weeks, of unilateral leg extensions with different set configurations but with identical work-to-rest ratios for each limb: a traditional configuration (4 sets of 8 repetitions, 10RM load, 3-min pause between sets) and an inter-repetition rest configuration (32 repetitions, 10RM load, 17.4 s of rest between each repetition). Mean propulsive velocity of the traditional sessions was lower than for inter-repetition rest sessions (0.48 ± 0.06 vs. 0.54 ± 0.06 m · s(-1); P < 0.001), while perceived exertion was higher (8.3 ± 0.9 and 6.56 ± 1.6 for traditional training and IRT; P = 0.002). One repetition maximum (RM), work with 10RM load, maximum mean propulsive power, maximum voluntary contraction and time to failure with 50% of maximum isometric force improved similarly in both legs (time effect, P < 0.001; effect size range, 0.451-1.190). Time and set configuration did not show significant main effects or interactions for cortical adaptations (motor-evoked potentials, short-interval intracortical inhibition, intracortical facilitation). There were no significant correlations between changes in cortical and peripheral neural adaptations and strength improvement. In conclusion, inter-repetition rest configuration was as effective as traditional training in improving muscle performance.

Arterial stiffness assessment by pulse wave velocity in postmenopausal women: comparison between noninvasive devices.

OBJECTIVE: This study aimed to ascertain the accuracy of measure arterial stiffness using the HUAWEI GT 3 Pro smartwatch and pOpmètre device against the SphygmoCor (algorithms: intersect tangent and maximum of the second derivate). METHODS: Twenty-three physically active postmenopausal women (age: 58.9 ± 3.2 years; body mass index: 26.3 ± 4.8 kg/m2) were recruited. Carotid-femoral pulse wave velocity, finger-toe pulse wave velocity, and wrist-finger pulse wave velocity were obtained using SphygmoCor, pOpmètre and HUAWEI GT 3 Pro devices in a randomized order. Additionally, the pulse mean carotid-femoral and finger-toe pulse transit time was registered for SphygmoCor and pOpmètre, respectively. RESULTS: Lower values of pulse wave velocity were recorded by HUAWEI in comparison with SphygmoCor with both algorithms, whereas no significant differences were detected between SphygmoCor and pOpmètre results. Pulse wave velocity values from SphygmoCor were positively correlated with pOpmètre results (r = 0.464 and r = 0.451 using intersect tangent and second derivative algorithms), whereas this was not the case with those obtained from HUAWEI. Coefficients of bias of Lin's concordance coefficients close to 1 (0.832 and 0.831 for intersect tangent and second derivative algorithm, respectively) and mean bias close to 0 from Bland-Altman analysis suggested an acceptable agreement between pulse wave velocity obtained from SphygmoCor and pOpmètre. CONCLUSIONS: Our results suggest an acceptable concordance of pulse wave velocity values recoded by SphygmoCor and pOpmètre, whereas this was not the case for data obtained from HUAWEI GT 3 Pro smartwatch. Therefore, the pOpmètre may be a viable alternative for assessing arterial stiffness, but measurement via the smartwatch device cannot be recommended.

Heart Rate Responses and Cardiovascular Adaptations to Resistance Training Programs Differing in Set Configuration: A Randomized Controlled Trial.

Purpose: This study explored the changes in blood pressure and cardiac autonomic modulation after training programs differin in set configuration. Methods: Thirty-nine individuals were randomly assigned to a traditional, rest-redistribution, or control group. Throughout five weeks, the traditional and rest-redistribution groups performed 10 sessions of four exercises with the same load, number of repetitions, and total rest time, but with different inter-set rest duration and frequency (traditional group: 4 sets of 8 repetitions, 10 repetition maximum load, 5 min rest between sets and exercises; rest-redistribution group: 16 sets of 2 repetitions, 1 min rest between sets, 5 min rest between exercises). Heart rate and heart rate recovery were recorded during each training session, and heart rate variability, baroreflex sensitivity and effectiveness, blood pressure, and blood pressure variability were evaluated at rest bedore and after the interventions. Results: During the sessions, traditional sets entailed greater peak heart rate compared to rest-redistribution (P = .018) but mean heart rate, minimum heart rate, and heart rate recovery were similar between training programs (P >.05). Baroreflex effectiveness was reduced after the traditional intervention (P = .013). No changes were detected for the rest of the cardiovascular variables obtained at rest after intervention (P > .05). Conclusions: Despite some differences in heart rate response during exercise, neither traditional nor rest-redistribution resistance training protocols produced changes in cardiac autonomic modulation, sympathetic vasomotor tone, and cardiac baroreflex sensitivity of young healthy active individuals. However, traditional sets affected the baroreflex effectiveness.

Cluster vs. traditional training programmes: changes in the force-velocity relationship.

This randomised controlled study examined the force-velocity relationship changes (force and velocity axis intercepts, slope and estimated maximum power) in response to 5-week training programmes differing in the set configuration. For each session, the traditional group performed 4 sets of 8 repetitions with 5 min of rest between sets and exercises, while the cluster group completed 16 sets of 2 repetitions with 1 min of rest between sets and 5 min between exercises. Both programmes were performed with the 10-repetition maximum load, including bench press, parallel squat, lat pull-down and leg curl exercises. Individual force-velocity profiles were obtained for bench press and squat using a linear velocity transducer before and after the intervention, along with lactate and mechanical performance during the intervention. Results showed in bench press similar changes of the force-velocity profile after both protocols (no shift of the slope and higher force and velocity axis intercept values). For the squat, significant changes in the slope (P = 0.001) and the velocity intercept (P = 0.002) towards a velocity profile were observed after cluster but not after traditional training. These results suggest that set configuration may modulate changes of force-velocity relationship, especially for squat.

Comparison of different regression models to fit the force-velocity relationship of a knee extension exercise.

The aims of this study were to compare the goodness of fit and the concurrent validity of three regression models of the force-velocity relationship in a unilateral knee extension exercise. The force-velocity relationship and the one-repetition-maximum load in the dominant and non-dominant leg were obtained in 24 male sports sciences students by a progressive protocol. Additionally, the maximum voluntary contraction (MVC) of the knee extensor muscles was recorded. Individual force-velocity relationships were obtained by the linear, quadratic polynomial and exponential regression models. Although the adjusted coefficients of determination of all three models were high, the polynomial model's coefficient was slightly but significantly higher than the rest of the models (p < 0.05), while the standard error of estimate was slightly higher for the linear than for polynomial model (p = 0.001). MVC was underestimated by F 0 calculated from the linear and polynomial models, while the maximum power was accurately estimated by the linear model. In summary, while the polynomial model revealed somewhat better fit, the linear model more accurately estimates the maximum power and provides the parameters of apparent physiological meaning. Therefore, we recommend using the linear model in research and routine testing of mechanical capacities of knee extensors.

Determination of rare earth and concomitant elements in magnesium alloys by inductively coupled plasma optical emission spectrometry.

An Inductively Coupled Plasma Optical Emission Spectrometry method for simultaneous determination of Al, Ca, Cu, Fe, In, Mn, Ni, Si, Sr, Y, Zn, Zr and rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in magnesium alloys, including the new rare earth elements-alloyed magnesium, has been developed. Robust conditions have been established as nebulizer argon flow rate of 0.5mLmin(-1) and RF incident power of 1500W, in which matrix effects were significantly reduced around 10%. Three acid digestion procedures were performed at 110°C in closed PFA vessels heated in an oven, in closed TFM vessels heated in a microwave furnace, and in open polypropylene tubes with reflux caps heated in a graphite block. The three digestion procedures are suitable to put into solution the magnesium alloys samples. From the most sensitive lines, one analytical line with lack or low spectral interferences has been selected for each element. Mg, Rh and Sc have been studied as internal standards. Among them, Rh was selected as the best one by using Rh I 343.488nm and Rh II 249.078nm lines as a function of the analytical lines. The trueness and precision have been established by using the Certified Reference Material BCS 316, as well as by means of recovery studies. Quantification limits were between 0.1 and 9mgkg(-1) for Lu and Pr, respectively, in a 2gL(-1) magnesium matrix solution. The method developed has been applied to the commercial alloys AM60, AZ80, ZK30, AJ62, WE54 and AE44.

Influence of relative abundance of isotopes on depth resolution for depth profiling of metal coatings by laser ablation inductively coupled plasma mass spectrometry.

A systematic study on the influence of relative abundance of isotopes of elements in the coating (A(c)) and in the substrate (A(s)) on both shape of time-resolved signals and depth resolution (Delta z) was performed for depth profile analysis of metal coatings on metal substrates by ultraviolet (266 nm) nanosecond laser ablation inductively coupled plasma quadrupole mass spectrometry. Five coated samples with coating thicknesses of the same order of magnitude (20-30 microm) were tested: nickel coating on aluminium, chromium and copper, and steel coated with copper and zinc. A laser repetition rate of 1 Hz and a laser fluence of 21 J cm(-2) were used. Five different depth profile types were established, which showed a clear dependence on A(c)/A(s) ratio. In general, depth profiles obtained for ratios above 1-10 could not be used to determine Delta z. We found that Delta z increased non-linearly with A(c)/A(s) ratio. The best depth profile types, leading to highest depth resolution and reproducibility, were attained in all cases by using the isotopes with low/medium A(c) values and with the highest A(s) values. In these conditions, an improvement of up to 4 times in Delta z values was achieved. The average ablation rates were in the range from 0.55 microm pulse(-1) for copper coating on steel to 0.83 microm pulse(-1) for zinc coating on steel, and the Delta z values were between 2.74 microm for nickel coating on chromium and 5.91 microm for nickel coating on copper, with RSD values about 5-8%.

Study of heterogeneities in steels and determination of soluble and total aluminium and titanium concentration by laser ablation inductively coupled plasma mass spectrometry.

A methodology for bulk analysis of Al and Ti and for determination of soluble and total Al and Ti concentration in steel samples by laser ablation inductively coupled plasma mass spectrometry was developed. The spatial distribution (both at surface and within the sample) of the insoluble fraction of Al and Ti was also qualitatively estimated. Certified reference materials (CRMs) SS-451 to 460 (carbon steel) and 064-1 (Nb/Ti interstitial free steel), from BAS, and JK 2D (carbon steel) and JK 37 (highly alloyed steel), from SIMR, were studied. It was demonstrated that the insoluble fraction of Al and Ti is heterogeneously distributed. A series of nine glass samples (fused beads) with fixed Fe content and different Al and Ti contents was prepared by melting appropriate amounts of Fe(2)O(3), Al(2)O(3) and TiO(2) with a lithium tetraborate-sodium carbonate mixture. Quantitative determinations were performed by using calibration graphs obtained from the synthetic fused beads, with (57)Fe as internal standard; line scan laser sampling mode was used, focusing the laser beam at the sample surface. The optimized laser operating parameters were: laser pulse energy of 1.5mJ, pulse repetition rate of 5Hz, scanning speed of 5microm s(-1) and preablation time of 20s. The concentrations obtained for bulk analysis of CRM samples corresponded with the certified values within the experimental uncertainty. An acceptable concordance between certified and found values was attained for the determination of soluble and total Al and Ti in CRM 064-1 sample.

Determination of major, minor and trace elements in cobalt-substituted lithium nickelate ceramic powders by inductively coupled plasma optical emission spectrometry.

An analytical method was developed for the determination of three major (Li, Ni and Co) and fourteen minor or trace elements (Al, Ba, Ca, Cu, Cr, Fe, K, Mg, Mn, Na, Si, Sr, Ti and V) in LiNi1-xCoxO2 (x=0.2-0.8) ceramic powders by inductively coupled plasma optical emission spectrometry. Sample dissolution was achieved by 25% nitric acid digestion in a microwave oven. For each element, an analytical line free from spectral interferences was selected. A detailed study of matrix effects over a wide interval of total excitation energy (TEE) lines (1.62-16.50 eV) was performed at near-robust plasma conditions. A remarkable enhancement in atomic lines with TEE<4 eV was noticed, whereas a significant reduction in atomic and ionic lines with TEE>4 eV was observed. The extrapolation to infinite dilution method was successfully used to overcome these nonspectroscopic interferences. Detection limits (3sigma) varied from 0.21 mg kg-1 for Sr to 49.7 mg kg-1 for Na. The precision of determination (obtained as the relative standard deviation) was lower than 1% for the major elements Li, Ni and Co and between 0.69 and 10% for minor and trace elements. The accuracy of the method ranged from 91 to 101% for major elements, and from 90 to 110%, or close to this range, for most of the impurities in both of the samples studied.