Biological basis for adoption of an isoline of Telenomus remus (Hymenoptera: Scelionidae) for an augmentative biological-control program for Spodoptera frugiperda (Lepidoptera: Noctuidae).

The widely distributed, polyphagous fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797), is one of the most important crop pests worldwide. The egg-parasitoid wasp, Telenomus remus Nixon, 1937, is frequently described as a possible control agent for S. frugiperda. We selected an isoline of T. remus and evaluated its parasitism potential (for 24 h) in S. frugiperda eggs, in laboratory conditions, and also its ability to fly at different temperatures and relative humidity levels, aiming to provide basic information about this isoline. The selected isoline maintained good flight capacity without affecting its parasitism efficiency or developing inefficient haplotypes for biological-control programs, compared across generations to a regularline laboratory-reared for more than 60 generations. The flight capacity of the isoline was best at 25-30 °C and relative humidity 70-90%.

Does the Muscle Action Duration Induce Different Regional Muscle Hypertrophy in Matched Resistance Training Protocols?

ABSTRACT: Diniz, RCR, Tourino, FD, Lacerda, LT, Martins-Costa, HC, Lanza, MB, Lima, FV, and Chagas, MH. Does the muscle action duration induce different regional muscle hypertrophy in matched resistance training protocols? J Strength Cond Res 36(9): 2371-2380, 2022-The manipulation of the muscle action duration (MAD) can influence the instantaneous torque along the range of motion, which can lead to adaptations of regional muscle hypertrophy. The aim of this study was to compare the effects of matched resistance training (RT) on the knee extension machine with different MAD in the cross-sectional area (CSA) responses within the quadriceps femoris (QF) and its muscles. Forty-four subjects were allocated into a control and 3 experimental groups. For a period of 10 weeks, subjects in the experimental groups performed the training protocols that were different only by the MAD: group 5c1e (5s concentric action [CON] and 1s eccentric action [ECC]; group 3c3e (3s CON and 3s ECC) and group 1c5e (1s CON and 5s ECC). Magnetic resonance imaging was performed (before and after the intervention) to determine the relative change (%) in CSA of the QF muscles along proximal (30%), middle (50%), and distal regions (70% distal of the femur). The change in CSA of the rectus femoris at the middle region are greater in 5c1e (6.8 ± 6.5%) and 1c5e (7.4 ± 6.0%) groups than 3c3e (3.4 ± 6.6%) and control groups (0.2 ± 1.8%). In addition, vastus lateralis at the distal region (5c1e = 15.9 ± 11.8%; 1c5e = 14.4 ± 10.0%) presenting greater increases in change of CSA than the others vastus only 5c1e (vastus lateralis [VI] = 5.0 ± 4.7%; vastus medialis [VM] = 4.2 ± 3.2%) and 1c5e groups (VI = 4.7 ± 3.6%; VM = 3.4 ± 3.1%). In conclusion, this study showed that matched RT protocols with different MAD resulted in different region-specific muscle hypertrophic across the individual muscles of QF.

Equalization of Training Protocols by Time Under Tension Determines the Magnitude of Changes in Strength and Muscular Hypertrophy.

ABSTRACT: Martins-Costa, HC, Lacerda, LT, Diniz, RCR, Lima, FV, Andrade, AGP, Peixoto, GH, Gomes, MC, Lanza, MB, Bemben, MG, and Chagas, MH. Equalization of training protocols by time under tension determines the magnitude of changes in strength and muscular hypertrophy. J Strength Cond Res 36(7): 1770-1780, 2022-The aim of this study was to investigate the effects of 2 training protocols equalized by tension (TUT) on maximal strength (1 repetition maximum [RM]), regional cross-sectional areas (proximal, middle, and distal), and total cross-sectional areas (sum of the regional cross-sectional areas) of the pectoralis major and triceps brachii muscles. Thirty-eight men untrained in resistance training participated in the study and were allocated under 3 conditions: Protocol 3s (n = 11; 12 repetitions; 3s repetition duration), Protocol 6s (n = 11; 6 repetitions; 6s repetition duration), and Control (n = 11; no training). Training protocols (10 weeks; bench press exercise) were equated for TUT (36 seconds per set), number of sets (3-4), intensity (50-55% of 1RM), and rest between sets (3 minutes). Analysis of variance was used to examine a percentage change in variables of interest across the 3 groups with an alpha level of 0.05 used to establish statistical significance. Protocols 3s and 6s showed no differences in the increase of total and regional muscle cross-sectional areas. There were no differences in regional hypertrophy of the pectoralis major muscle. In the triceps brachii muscle, the increase in distal cross-sectional area was greater when compared with the middle and proximal regions. Both experimental groups had similar increases in the 1RM test. In conclusion, training protocols with the same TUT promote similar strength gains and muscle hypertrophy. Moreover, considering that the protocols used different numbers of repetitions, the results indicate that training volumes cannot be considered separately from TUT when evaluating neuromuscular adaptations.

Resistance training intervention performed with different muscle action durations influences the maximal dynamic strength without promoting joint-angle specific strength gains.

The present study investigated the effect of 10-week matched (range of motion, volume, intensity, rest, and repetition duration) training protocols with varying muscle action duration (MAD) on maximal voluntary isometric contraction (MVIC) test at eight different knee angles and one-repetition maximum (1RM) test after in seated knee extensor machine. Forty women were allocated into one control and three training groups with varying MAD: 5C1E (5s concentric action [CON] and 1s eccentric action [ECC]), 3C3E (3s CON and 3s ECC), and 1C5E (1s CON and 5s ECC). All training groups (5C1E, 3C3E, and 1C5E) showed a greater relative response in 1RM performance than the control group (0.1 ± 3.5%, p ≤ 0.05). The 1C5E group presented greater relative increases in the 1RM performance (22.1 ± 11.6%) compared to 5C1E (13.6 ± 9.2%; p ≤ 0.05) and 3C3E (14.1 ± 5.5%, p ≤ 0.05) groups. The training groups increased the MVIC performance more than the control group (p ≤ 0.05), although there were no significant differences between the training groups. This study demonstrated that isoinertial resistance training protocols with shorter CON MAD showed greater maximum dynamic strength performance response than matched training protocols with other MAD configurations. However, the configuration of MAD did not induce angle-specificity to increase the maximum isometric strength.

Is Performing Repetitions to Failure Less Important Than Volume for Muscle Hypertrophy and Strength?

Lacerda, LT, Marra-Lopes, RO, Diniz, RCR, Lima, FV, Rodrigues, SA, Martins-Costa, HC, Bemben, MG, and Chagas, MH. Is performing repetitions to failure less important than volume for muscle hypertrophy and strength? J Strength Cond Res 34(5): 1237-1248, 2020-The aim of this study was to investigate the effects of muscle failure (MF) or not to MF (NMF) training on strength and muscle hypertrophy relative gains (average and individual data). Ten men untrained in resistance training participated in the study. Each leg was allocated in 1 of 2 unilateral training protocols (MF or NMF with equal volume) on knee extension exercise. Both protocols were performed with 3-4 sets, 3 minutes' rest, and 55-60% of one repetition maximum (1RM). Rectus femoris and vastus lateralis muscles cross-sectional area (CSA), maximal muscle strength (1RM and maximal voluntary isometric contraction), and muscular endurance (maximum number of repetition) were assessed before and after 14 weeks. In addition, neuromuscular activation by normalized root mean square of the electromyographic signal (EMGRMS) was measured in 2nd and 35th training sessions. The average results showed that both training protocols were similarly effective in inducing increases in strength and muscle hypertrophy gains. However, individual analysis data suggest that NMF protocol with equal volume may promote similar or even greater muscle hypertrophy (vastus lateralis) and muscular endurance performance when compared with MF protocol. Also, normalized EMGRMS responses analyzed during 2nd and 35th sessions were similar in MF and NMF protocols for rectus femoris and vastus lateralis muscles. In conclusion, MF and NMF protocol conducted with the same total repetition numbers produced similar maximal muscle strength performance and neuromuscular activation. Nevertheless, NMF training could be a more appropriate strategy to increase muscle hypertrophy (vastus lateralis) and muscular endurance performance in untrained individuals when compared with MF.

Longer Concentric Action Increases Muscle Activation and Neuromuscular Fatigue Responses in Protocols Equalized by Repetition Duration.

Lacerda, LT, Costa, CG, Lima, FV, Martins-Costa, HC, Diniz, RCR, Andrade, AGP, Peixoto, GHC, Bemben, MG, and Chagas, MH. Longer concentric action increases muscle activation and neuromuscular fatigue responses in protocols equalized by repetition duration. J Strength Cond Res 33(6): 1629-1639, 2019-The aim of this study was to investigate the impact of protocols equalized by the repetition duration but composed of different concentric (CON) and eccentric (ECC) durations on muscle activation and neuromuscular fatigue. Seventeen males with previous experience in resistance training performed 3 training protocols (A - 2 second CON: 4 second ECC; B - 3 second CON: 3 second ECC; and C - 4 second CON: 2 second ECC) with the Smith machine bench press exercise, all with 3 sets, 6 repetitions, 3 minutes' rest, and 60% of 1RM. The normalized root mean square of the electromyographic signal (EMGRMS) and mean frequency electromyography (EMGMF) for pectoralis major and triceps brachii muscles were calculated for second and fifth repetitions in each set. The results showed an EMGMF decrease across the repetitions accompanied by a progressive increase of the EMGRMS across the repetitions for all protocols and muscles. The EMGRMS was higher in protocol C when compared with protocol A and B for pectoralis major. The EMGMF was lower in protocols B and C than in protocol A for pectoralis major throughout the sets and repetitions. A higher EMGRMS and a lower EMGMF were observed in protocols B and C compared with protocol A for triceps brachii, solely in the fifth repetition. In conclusion, training protocols conducted with the same repetition duration, but with different concentric and eccentric durations, produce distinct muscle activation and neuromuscular fatigue responses, in which performing longer concentric durations could be the more appropriate strategy to increase muscle activation and neuromuscular fatigue.

Variations in Repetition Duration and Repetition Numbers Influence Muscular Activation and Blood Lactate Response in Protocols Equalized by Time Under Tension.

The aim of this study was to investigate the impact of protocols equalized by the time under tension (TUT) but composed of different repetition durations and repetitions numbers on muscle activation and blood lactate concentration. Twenty-two males with previous experience in resistance training performed 2 training protocols (A and B) with the Smith machine bench press exercise, both with 3 sets, 3 minutes' rest, and 60% of 1 repetition maximum (1RM). Protocol A consisted of 6 repetitions with a 6-second repetition duration for each repetition, whereas in Protocol B the subjects performed 12 repetitions with a 3-second repetition duration for each repetition. Muscular activation was measured in the anterior deltoid, pectoralis major, and triceps brachii muscles while performing the 2 protocols, and the normalized root mean square of the electromyographic signal (EMGRMS) was calculated for each set. Blood lactate concentrations were measured during and until 12 minutes after the completion of each protocol. The results showed that the EMGRMS of all muscles increased during the sets and was higher in Protocol B when compared with Protocol A. Likewise, blood lactate concentrations also increased throughout the sets and were higher in Protocol B both during and after the completion of each training session. The data obtained in this study show that training protocols conducted with the same TUT, but with different configurations, produce distinct neuromuscular and metabolic responses so that performing higher repetition numbers with shorter repetition durations might be a more appropriate strategy to increase muscle activation and blood lactate concentration.

Does rest interval between unilateral exercise protocols influences on contralateral neuromuscular responses in untrained individuals?

INTRODUCTION: Effects on strength performance and muscle activation in the contralateral limb have been observed after training with the ipsilateral limb (IL). Cross fatigue effects in the contralateral limb (CL) can occur at intervals of up to 48 h after a training session performed with the ipsilateral limb. The objective of this study was to verify the effect of a training session in the ipsilateral limb, on the strength and activation of the muscles in the contralateral limb also submitted to the training protocol. METHODS: 10 untrained men (mean ± SD: age = 23.7 ± 4.9 years) performed unilateral knee extension with both limbs in equated protocols, in two conditions with different intervals between limbs - 20 min and 24 h. RESULTS: There were no differences in the comparison of the force produced between the pre x post interventions with the CL limb, as well as in the activation of the quadriceps during its performance. These results were similar for the two different intervals between the protocols. CONCLUSION: It was concluded that when the CL member performs the protocol after the IL, the responses in the CL depend mainly on the requirement imposed on the protocol performed by this member, without influence of the training protocol performed previously with the IL member.

Differential contribution of elbow flexion and knee extension on vascular and hemodynamic parameters and arterial stiffness indices after acute strength exercise in young adults.

BACKGROUND: Different types of exercise, performed acutely or chronically, have different repercussions on central hemodynamics, arterial stiffness, and cardiac function. In this study, we aim to compare the effects of acute elbow flexion (EFlex) and knee extension (KExt) exercises on vascular and hemodynamic parameters and arterial stiffness indices in healthy young adults. METHODS: Young adults (20 to 39 years) underwent randomized muscle strength tests to obtain 1 repetition maximum (1RM) for elbow flexion (EFlex) and knee extension (KExt). After a minimum interval of 48 h, cardiovascular parameters were assessed using Mobil-O-Graph® (Mobil-O-Graph, IEM, Germany) at three-time points: at baseline (before exercise), immediately after elbow flexion or knee extension exercises with a load corresponding to 50% of 1RM (T0) and after 15 min of rest (T15). RESULTS: Immediately after exercise (T0), peripheral systolic blood pressure, peripheral pulse pressure, central systolic blood pressure, and central pulse pressure were significantly higher in KExt than EFlex (Δ 3.13; Δ 3.06; Δ 5.65; Δ 5.61 mmHg, respectively). Systolic volume, cardiac output, and cardiac index were significantly higher immediately after KExt when compared with EFlex (Δ 4.2 ml; Δ 0.27 ml/min and 0.14 l/min*1/m2, respectively). The reflection coefficient and the pulse wave velocity were also significantly higher at T0 in KExt compared to EFlex ( Δ 8.59 and Δ 0.12 m/sec, respectively). CONCLUSION: Our results show differential contribution of muscle mass in vascular and hemodynamic parameters evaluated immediately after EFlex and KExt. In addition, our study showed for the first time that the reflection coefficient, an index that evaluates the magnitude of the reflected waves from the periphery, was only affected by KExt.

Normalization of the electromyography amplitude during a multiple-set resistance training protocol: Reliability and differences between approaches.

The first aim was to investigate the impact of different electromyography (EMG) parameters as a reference to normalize the EMG amplitude of the superficial quadriceps femoris muscles across different sets of a knee extension exercise. The second aim is to examine the reliability between days of the EMG parameters used as a reference. Eleven young males attended the laboratory on 4 different days and performed one repetition maximum test, maximumvoluntary isometric contractions, and a resistance training protocol until failure. Surface EMG was placed over the rectus femoris, vastus lateralis, and vastus medialis muscles. Seven EMG parameters were calculated from the tasks and used to normalize EMG amplitude measured during the resistance training protocol. A repeated-measures two-way ANOVA was used (normalized EMG amplitude × set) to compare normalized EMG across sets, while an intraclass correlation coefficient, coefficient of variation, and Bland-Altman plots were used to calculate the intra-day reliability of the EMG parameters. The present investigation showed that normalized EMG amplitude of the superficial muscles of the quadriceps measured during a knee extension exercise is influenced by the EMG parameter and depends on the muscle. While rectus femoris and vastus lateralis normalized EMG amplitude presented one parameter among seven showing similar value to the other parameters, VM showed two. Lastly, all EMG parameters for all muscles presented an overall excellent reliability and agreement between days.

Training in the Initial Range of Motion Promotes Greater Muscle Adaptations Than at Final in the Arm Curl.

OBJECTIVE: The effects of ROM manipulation on muscle strength and hypertrophy response remain understudied in long-term interventions. Thus, we compared the changes in strength and regional muscle hypertrophy after training in protocols with different ranges of motion (ROM) in the seated dumbbell preacher curl exercise using a within-participant experimental design. DESIGN AND METHODS: Nineteen young women had one arm randomly assigned to train in the initial ROM (INITIALROM: 0°-68°; 0° = extended elbow) while the contralateral arm trained in the final ROM (FINALROM: 68°-135°), three times per week over an eight-week study period. Pre- and post-training assessments included one repetition maximum (1RM) testing in the full ROM (0°-135°), and measurement of biceps brachii cross-sectional area (CSA) at 50% and 70% of humerus length. Paired t-tests were used to compare regional CSA changes between groups, the sum of CSA changes at 50% and 70% (CSAsummed), and the strength response between the training protocols. RESULTS: The INITIALROM protocol displayed a greater CSA increase than FINALROM protocol at 70% of biceps length (p = 0.001). Alternatively, we observed similar increases between the protocols for CSA at 50% (p = 0.311) and for CSAsummed (p = 0.111). Moreover, the INITIALROM protocol displayed a greater 1RM increase than FINALROM (p < 0.001). CONCLUSIONS: We conclude that training in the initial angles of elbow flexion exercise promotes greater distal hypertrophy of the biceps brachii muscle in untrained young women. Moreover, the INITIALROM condition promotes a greater dynamic strength increase when tested at a full ROM compared to the FINALROM.

Bj-PRO-10c, as an allosteric regulator of argininosuccinate synthase, is a potential therapy for neuroblastoma metastasis.

Cancer is a global public health issue. Neuroblastoma (NB) originates from any tissue of the sympathetic nervous system, and the most affected site is the abdomen. The adrenal gland is the primary site in 38% of cases. Approximately 50% of patients have metastatic disease at diagnosis, and bone marrow is often affected. Metastatic disease is characterized by the spreading of cancer cells that are frequently resistant to chemotherapy and radiotherapy from the primary tumor to other specific parts of the body and is responsible for 90% of cancer-related deaths. Increasing evidence has indicated that nitric oxide (NO) signaling is implicated in the pathophysiology of many types of cancer, particularly in tumorigenesis and cancer progression. However, the effect of NO on metastasis cannot be easily classified as prometastatic or antimetastatic. An understanding at the molecular level of the role of NO in cancer will have profound therapeutic implications for the diagnosis and treatment of disease. Here, the proline-rich decapeptide isolated from Bothrops jararaca venom (Bj-PRO-10c) that enhances and sustains the generation of NO was used to unravel the role of metabolic NO in steps of metastasis. Bj-PRO-10c showed an antimetastatic effect, mainly by interfering with actin cytoskeleton rearrangement, controlling cell proliferation, and decreasing the seeding efficiency of NB in metastatic niches. Therefore, we proposed that an approach for controlled NO induction with the right molecular strategies can hopefully inhibit metastasis and increase the lifespan of NB patients.

The effect of different resistance training protocols equalized by time under tension on the force-position relationship after 10 weeks of training period.

This study investigated the impact of performing two equalized resistance training (RT) protocols for 10 weeks that differ only by repetition duration and number in the force-position and EMG-position relationship. Participants performed an equalized (36 s of time under tension; 3-4 sets; 3 min between sets; 50-55% of one-repetition maximum; 3× week) RT intervention on the bench press and the only different change between protocols was repetition number (RN; 12 vs.6) or duration (RD; 3 s vs. 6 s). Two experimental groups (RN12RD3, n = 12; and RN6RD6, n = 12) performed the RT, while one group was the control (Control, n = 11). Maximal isometric contractions at 10%, 50% and 90% of total bench press range of motion were performed pre- and post-RT, while electromyography was recorded. It demonstrated an increase in isometric force (+14% to 24%, P < 0.001) shifting up the force-position relationship of the training groups after RT, although no difference was between training groups compared to the Control. Neuromuscular activation from pectoralis major presented an increase after training for both RT groups (+44%; P < 0.001) compared to the Control. However, although not significantly different, triceps brachii also presented an increase depending on the protocol (+25%). In conclusion, 10 weeks of an equalized RT with longer RN and shorter RD (or opposite) similarly increases the ability to produce maximal isometric force during the bench exercise across different angles, while neuromuscular activation of the pectoralis major partially explained the shift-up of the force-position relationship after training.

Partial range of motion training elicits favorable improvements in muscular adaptations when carried out at long muscle lengths.

The study compared changes in strength and regional muscle hypertrophy between different ranges of motion (ROM) in the knee extension exercise. Forty-five untrained women were randomized to either a control group or to perform the exercise in one of the following 4 groups (0°=extended knee): Full ROM (FULLROM: 100°-30° of knee flexion); Initial Partial ROM (INITIALROM: 100°-65°); Final Partial ROM (FINALROM: 65°-30°); Varied ROM (VARROM: daily alternation between the ROM of INITIALROM and FINALROM). Pre- and post-training assessments included one repetition maximum (1RM) testing in the ROM corresponding to the initial, final and full ROM, and measurement of cross-sectional areas of the rectus femoris and vastus lateralis muscles at 40%, 50%, 60% and 70% of femur length in regard to regional muscle hypertrophy. Results showed that the INITIALROM group presented a greater relative increase than all groups at 70%, and at 50% and 60% the increases were greater than FINALROM, FULLROM, and non-training control (CON) groups. Moreover, FINALROM group presented similar changes compared to the CON group at 60% and 70%. In regard to 1RM, FINALROM and INITIALROM groups presented greater relative increases at the ROM trained, and no group showed greater increases than VARROM or INITIALROM, regardless the ROM tested. In conclusion, partial ROM training in the initial phase of the knee extension exercise promoted greater relative hypertrophy in certain muscle regions than training in other ROM configurations, and no group promoted a greater 1RM increase than VARROM group, which showed similar 1RM increases in the different ROMs tested.

Similar Inflammatory Adaptation in Women following 10 Weeks of Two Equalized Resistance Training with Different Muscle Action Duration.

This study is aimed at evaluating the profile of inflammatory markers and components of redox regulation in untrained women after 10 weeks of resistance training using equalized protocols but different muscle action duration (MAD). Twenty-two women underwent progressive resistance training exercising the knee extensor muscles for 10 weeks-3x/week, with 3-5 sets of 6 repetitions at 50% of the 1 repetition maximum strength test (1RM), with a rest of 180 s between the series, following the training protocol (i) 5 s of concentric muscle action for 1 s of eccentric muscle action (5C-1E) and (ii) 1 s of concentric muscle action for 5 s of eccentric muscle action (1C-5E). Quadriceps muscle hypertrophy maximum strength (1RM) and redox regulation/muscle damage/inflammatory markers (CAT, SOD, TBARS, FRAP, CH, LDH, CXCL8, and CCL2) were evaluated. Plasma markers were evaluated before and 30 minutes after the first and last training sessions. A similar gain in hypertrophy and maximum strength was observed in both groups. However, in the 5C-1E, a significant major effect was observed for SOD (F 1.19 = 10.480, p = 0.004) and a significant major time effect, with a reduction in the last training session, was observed for CXCL8 (F 1.37 = 27.440, p < 0.001). In conclusion, similar protocols of resistance training, with different MAD, produced similar inflammatory and adaptive responses to strength training. As the training load is progressive, the maintenance of this inflammatory and redox regulation profile suggests an adaptive response to the proposed strength training.

Acute physiological responses with varying load or time under tension during a squat exercise: A randomized cross-over design.

OBJECTIVES: Despite advancements in resistance training (RT) methods, the acute metabolic and neuromuscular responses to time under tension (TUT) and load remains poorly understood. The aim of the present study was to investigate how TUT or resistance load impact muscular activation and blood lactate during an RT session. DESIGN: A randomized cross-over design. METHODS: Participants performed a squat exercise in three different conditions: baseline protocol (BPRO; three sets of eight repetitions with four second repetitions at 60% of 1RM) long duration protocol (LDPRO: six second repetitions) and high load protocol (HLPRO: 70% 1RM). RESULTS: Muscular activation of the vastus lateralis and biceps femoris, and blood lactate were assessed. Blood lactate was ∼19% and ∼26% higher after set one and three in LDPRO compared to BPRO (P≤0.011) and ∼17% higher for LDPRO compared to HLPRO (P=0.002). Additionally, blood lactate was ∼17% higher for HLPRO compared to BPRO after the third set of exercise (P=0.003). Vastus lateralis activation was ∼10% higher for HLPRO compared to BPRO and LDPRO for sets one and two. Biceps femoris activation was ∼17% higher for HLPRO compared to BPRO for set one (P= 0.023) while for set two HLPRO was greater than BPRO and LDPRO (∼19% and ∼14%, respectively; P≤0.007). CONCLUSIONS: Squatting with higher TUT caused a greater impact on the metabolic responses than lower TUT or higher loads, whereas an increase in training load resulted in greater muscle activation than higher TUT or lower training load.

Resistance training with different repetition duration to failure: effect on hypertrophy, strength and muscle activation.

BACKGROUND: This study investigated the effects of two 14-week resistance training protocols with different repetition duration (RD) performed to muscle failure (MF) on gains in strength and muscle hypertrophy as well as on normalized electromyographic (EMG) amplitude and force-angle relationships. METHODS: The left and right legs of ten untrained males were assigned to either one of the two protocols (2-s or 6-s RD) incorporating unilateral knee extension exercise. Both protocols were performed with 3-4 sets, 50-60% of the one-repetition maximum (1RM), and 3 min rest. Rectus femoris and vastus lateralis cross-sectional areas (CSA), maximal voluntary isometric contraction (MVIC) at 30o and 90o of knee flexion and 1RM performance were assessed before and after the training period. In addition, normalized EMG amplitude-angle and force-angle relationships were assessed in the 6th and 39th experimental sessions. RESULTS: The 6-s RD protocol induced larger gains in MVIC at 30o of knee angle measurement than the 2-s RD protocol. Increases in MVIC at 90o of knee angle, 1RM, rectus femoris and vastus lateralis CSA were not significant between the 2-s and 6-s RD protocols. Moreover, different normalized EMG amplitude-angle and force-angle values were detected between protocols over most of the angles analyzed. CONCLUSION: Performing longer RD could be a more appropriate strategy to provide greater gains in isometric maximal muscle strength at shortened knee positions. However, similar maximum dynamic strength and muscle hypertrophy gains would be provided by protocols with different RD.

Ageing and the natural history of dry eye disease: A prospective registry-based cross-sectional study.

PURPOSE: To investigate the impact of ageing on ocular surface parameters, and empirically determine optimal prognostic cut-off ages for clinical markers of dry eye disease, aqueous tear deficiency, and meibomian gland dysfunction. METHODS: A total of 1331 community residents (785 females, 546 males; mean ± SD age, 38 ± 19 years) were recruited in a prospective registry-based cross-sectional study. Dry eye symptomology, ocular surface characteristics, and tear film quality were evaluated for each participant within a single clinical session, in accordance with the global consensus recommendations of the TFOS DEWS II reports. RESULTS: Multivariate regression analysis demonstrated positive associations between ageing and clinical markers of dry eye disease (all p ≤ 0.001). The Youden-optimal prognostic cut-off ages for signs of meibomian gland dysfunction occurred during the third decade of life (24-29 years); the optimal predictive ages for lid wiper epitheliopathy, tear film instability, hyperosmolarity, and dry eye symptoms occurred during the fourth decade of life (31-38 years); while the optimal prognostic thresholds for signs of aqueous tear deficiency and ocular surface staining occurred in the fifth and sixth decades of life (46-52 years). CONCLUSIONS: Advancing age is a significant risk factor for dry eye disease, which represents a growing public health concern with the ageing population worldwide. Signs of meibomian gland dysfunction appeared earlier in the natural history of disease progression, and the brief delay prior to the development of other clinical dry eye signs might represent a window of opportunity for preventative interventions in the young adult age group.

The Effects of Altering the Concentric/Eccentric Phase Times on EMG Response, Lactate Accumulation and Work Completed When Training to Failure.

This study compared the electromyographic response, the blood lactate concentration (BLC), and the maximum number of repetitions (MNR) between protocols of different concentric/eccentric duration taken to muscle failure. This comparison may help to understand how different concentric/eccentric duration may influence performance and the central and metabolic responses in trained men. Seventeen strength-trained men performed two protocols in a counterbalanced design. Three sets of the Smith bench press exercise were performed to failure at 60% of the one-repetition maximum (1RM) using each protocol (4-s concentric/2-s eccentric [4 s: 2 s]; and 2-s concentric/4-s eccentric [2 s: 4 s]). The normalized root mean square (EMGRMS) and the mean frequency (EMGMF) of the electromyographic signals for the pectoralis major and the triceps brachii were compared in the first, middle, and last repetitions. The BLC was assessed at rest, during and after the test sessions. To compare the EMG and BLC, a 3-way ANOVA with repeated measures with a post hoc Tukey's test was used. To compare the MNR performed across the sets, an ANOVA-type rank test with the Dunn's post hoc test was used. The ANOVA indicated a greater EMGRMS for Protocol 4 s: 2 s in the pectoralis major and a lower EMGMF for Protocol 4 s: 2 s in the triceps brachii at the middle and last repetitions. Both protocols increased the EMGRMS and decreased the EMGMF across repetitions. Despite the results show different levels of activation and neuromuscular fatigue between protocols, the BLC and the MNR were similar.

Biology at Different Temperatures, Thermal Requirements, and Ecological Zoning of Opogona sacchari (Lepidoptera: Tineidae).

The banana moth, Opogona sacchari (Bojer, 1856), is a polyphagous pest that causes serious damage to different crops around the world, particularly to bananas in southern Brazil. The insect is designated a quarantine pest in several countries including Argentina, the main consumer market for bananas produced in southern Brazil. To provide support for the management of O. sacchari, the present study investigated the biology and thermal requirements at eight temperatures (18, 22, 25, 28, 30, 32, 33, and 34 ± 1°C) and constructed a fertility life table at five temperatures (18, 22, 25, 28, and 30 ± 1°C). Above 30°C, the mortality of all life stages was 100%; the best temperature for development was 25°C. Based on this information, an ecological zoning of the pest was developed for Brazil. The lower temperature threshold was 8.6°C. The zoning indicated that the pest does not occur in regions with warmer climates, corresponding to the actual distribution of this pest in Brazil.