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The aim of this study was to examine the effects of incline plyometrics training on muscle activation and architecture during vertical jumping and maximum strength. Twenty male participants were divided in two training groups which followed after a 4 week training program. The incline plyometrics group (n = 10) trained by performing consecutive jumps on an inclined surface (15°) while the plane plyometrics (PP) group (n = 10) performed the same jumps on a plane surface. Both groups trained four times per week and performed 8 sets of 10 jumps in each session. Subjects performed squat jumps, counter movement jumps and drop jumps (DJ) prior to and immediately after the training period, while the electromyographic activity of the medial gastrocnemius (MGAS) and tibialis anterior muscles and the architecture of MGAS were recorded. Maximal isokinetic and isometric strength of the plantar flexors were performed. Analysis of variance showed that only the IP group improved fast DJ height performance by 17.4 and 14.4% (20 and 40 cm, p < 0.05). This was accompanied by a significantly higher MGAS activity during the propulsion phase (24% from 20 cm and 50% from 40 cm, p < 0.05) of the DJ and a longer working fascicle length (5.08%, p < 0.05) compared with the PP group. There were no significant changes in isokinetic and isometric strength of the plantar flexors after training for both groups. The increase of jumping performance, after incline plyometrics should be taken into consideration by coaches, when they apply hopping exercise to improve explosiveness of the plantar flexors.

The purpose of this study was to compare the effects of an Olympic weight lifting (OL), a plyometric (PL), and combined weight lifting + plyometric (WP) training program on vertical jump (VJ) biomechanics. Thirty-six men were assigned randomly to 4 groups: PL group (n = 9), OL group (n = 9), WP group (), and control (C) group (n = 8). The experimental groups trained 3 d.wk, for 8 weeks. Sagital kinematics, VJ height, power, and electromyographic (EMG) activity from rectus femoris (RF) and medial gastrocnemius (GAS) were collected during squat jumping and countermovement jumping (CMJ) before and after training. The results showed that all experimental groups improved VJ height (p < 0.05). The OL training improved power and muscle activation during the concentric phase of the CMJ while the subjects used a technique with wider hip and knee angles after training (p < 0.05). The PL group subjects did not change their CMJ technique although there was an increase in RF activation and a decrease of GAS activity after training (p < 0.05). The WP group displayed a decline in maximal hip angle and a lower activation during the CMJ after training (p < 0.05). These results indicate that all training programs are adequate for improving VJ performance. However, the mechanisms for these improvements differ between the 3 training protocols. Olympic weight lifting training might be more appropriate to achieve changes in VJ performance and power in the precompetition period of the training season. Emphasis on the PL exercises should be given when the competition period approaches, whereas the combination of OL and PL exercises may be used in the transition phases from precompetition to the competition period.

This study examined fatigue profile during intermittent exercise in 10 men with mild to moderate mental retardation (MR) and 10 men without mental retardation (C). They performed 4 x 30s maximal knee extensions and flexions with 1-min rest on an isokinetic dynamometer. Peak torque of flexors (PTFL) and extensors (PTEX), total work (TW), and lactate were measured. Fatigue was calculated as the magnitude of decline (%) in PTFL, PTEX, and TW and as rate of decline (linear slope) in TW from 1st to 4th set. MR had lower PTFL, PTEX, TW, and lactate throughout the protocol than C, while pre-motor time was greater in MR vs. C (p<0.05). MR demonstrated a delayed pattern of reduction in muscular performance. Lower values were observed in MR vs. C in the magnitude of decline for PTEX and TW and the rate of decline for TW. In conclusion, MR exhibit a different fatigue profile during intermittent exercise than C. The lower magnitude and decline rate in neuromuscular performance in MR during intermittent exercise is associated with their lower peak strength, short-term anaerobic capacity, and lactate accumulation. Rehabilitation and sport professionals should consider the differences in fatigue profile when designing intermittent exercise programs for MR., (Copyright 2009 Elsevier Ltd. All rights reserved.)

This study examined the maturation pattern of fatigue resistance (FR) from childhood to adulthood in females and males during high-intensity intermittent exercise and compared FR between females and males in childhood and adolescence. Thirty males (boys 11.3 +/- 0.5 years, teen-males 14.7 +/- 0.3 years, men 24.0 +/- 2.1 years) and 30 females (girls 10.9 +/- 0.6 years, teen-females 14.4 +/- 0.7 years, women 25.2 +/- 1.4) participated in this study. They performed high-intensity intermittent exercise (4 x 18 maximal knee flexions and extensions with 1-min rest) on an isokinetic dynamometer at 120 degrees s(-1). Peak torque of flexors (PTFL) and extensors (PTEX), and total work (TW) were measured. FR was calculated as % of PTEX, PTFL, and TW in 4th versus 1st set. FR was greater (P < 0.05) in boys versus teen-males and men, and in teen-males versus men. In females, FR was greater (P < 0.05) in girls versus teen-females and women, but not different between teen-females and women. FR was not different in boys versus girls and in teen-males versus teen-females. FR for PTFL, PTEX, and TW correlated negatively (P < 0.001) with the respective peak values (r = -0.68 to -0.84), and FR for TW with peak lactate (r = -0.58 to -0.69). In addition, age correlated (P < 0.01) with FR for males (r = -0.75) and females (r = -0.55). In conclusion, FR during high-intensity intermittent exercise undergoes a gradual decline from childhood to adulthood in males, while in females the adult profile establishes at mid-puberty (14-15 years). The maturation profile of FR in males and females during development appears to reflect the maturation profiles of peak torque, short-term muscle power, and lactate concentration after exercise.

Purpose: The aim of this study was to evaluate the effectiveness of a strength and aerobic interval training program on arm-cranking economy, aerobic capacity, and gross motor function in children and adolescents with spastic diplegic cerebral palsy (CP)., Methods: Seven subjects (five females, two males; mean age 15.9, range 14-18 yr) participated in a 12-wk aerobic interval and strength training program, three times per week, 70 min per session. The aerobic interval training required the subjects to perform 60-m uphill walking repetitions. Six individuals (four females, two males; mean age 15.7, range 14-17 yr) who did not receive the training program served as controls. Pre- and postexercise tests were performed to assess changes in arm-cranking economy, aerobic capacity, and gross motor function., Results: The results demonstrated significant (P < 0.05) reductions in the oxygen cost of arm cranking (mean +/- SD: pre: 13.2 +/- 3.22 mL x kg(-1) x min(-1), post: 12.7 +/- 3.38 mL x kg(-1) x min(-1)) and %VO2peak (pre: 75.8 +/- 3.55%, post: 61.8 +/- 7.47%) in the training group. Significant (P < 0.05) increases in aerobic capacity (pre: 17.5 +/- 4.45 mL x kg(-1) x min(-1), post: 20.8 +/- 5.93 mL x kg(-1) x min(-1)) were also noted for the training group. Significant (P < 0.05) improvements in gross motor function measures were also noted in the training group (pre: 30.35%, post: 33.85%)., Conclusion: These findings demonstrate that the application of a 12-wk strength and aerobic interval training program reduced the oxygen cost of arm cranking, improved aerobic capacity, and improved gross motor function in children and adolescents with CP.

The purpose of this study was to examine the effects of external load on vertical ground reaction force, and linear and angular kinematics, during squats. Eight males aged 22.1 +/- 0.8 years performed maximal concentric squats using loads ranging from 7 to 70% of one-repetition maximum on a force plate while linear barbell velocity and the angular kinematics of the hip, knee and ankle were recorded. Maximum, average and angle-specific values were recorded. The ground reaction force ranged from 1.67 +/- 0.20 to 3.21 +/- 0.29 times body weight and increased significantly as external load increased (P < 0.05). Bar linear velocity ranged from 0.54 +/- 0.11 to 2.50 +/- 0.50 m x s(-1) and decreased significantly with increasing external load (P < 0.05). Hip, knee and ankle angles at maximum ground reaction force were affected by external load (P < 0.05). The force-barbell velocity curves were fitted using linear models with coefficients (r2) ranging from 0.59 to 0.96. The results suggest that maximal force exertion during squat exercises is not achieved at the same position of the lower body as external load is increased. In contrast, joint velocity coordination does not change as load is increased. The force-velocity relationship was linear and independent from the set of data used for its determination.

Background: A number of reviews have collated information on the impact of warming-up, physical exertion and recovery strategies on physical, subjective and physiological markers in soccer players yet none have solely analyzed their potential effects on components of kicking performance. Objective: To systematically analyse the influence of warm-up, exercise and/or recovery-related strategies on kicking performance in male soccer players and provide a critical appraisal on research paradigm related to kicking testing constraints and data acquisition methods. Methods: A systematic literature search was performed (until July 2020) in PubMed, Web of Science, SPORTDiscus, Scopus and ProQuest. Studies in male soccer populations, which included the effects of warm-up routines, physical exercise and/or recovery-related interventions, reported on comparisons pre–post or between experimental conditions and that computed at least one measure of kicking kinematics and/or performance were considered. Methodological quality and risk of bias were determined for the included studies. Constraints related to kicking testing and data acquisition methods were also summarized and discussed. Results: Altogether, 52 studies were included. Of these, 10 examined the respective effects of a warm-up, 34 physical exercise, and 21 recovery-related strategies. The results of eight studies showed that lower limb kinematics, kicking accuracy or ball velocity were improved following warm-ups involving dynamic but not static stretching. Declines in ball velocity occurred notably following intermittent endurance or graded until exhaustion exercise (three studies in both cases) without inclusion of any ball skills. In contrast, conflicting evidence in five studies was observed regarding ball velocity following intermittent endurance exercise interspersed with execution of ball skills. Kicking accuracy was less frequently affected by physical exercise (remained stable across 14 of 19 studies). One investigation indicated that consumption of a carbohydrate beverage pre- and mid-exercise demonstrated benefits in counteracting the potentially deleterious consequences of exercise on ball velocity, while four studies reported conflicting results regarding kicking accuracy. Most evidence synthesized for the interventions demonstrated moderate level (77%) and unclear-to-high risk of bias in at least one item evaluated (98%). The main limitations identified across studies were kicks generally performed over short distances (50%), in the absence of opposition (96%), and following experimental instructions which did not concomitantly consider velocity and accuracy (62%). Also, notational-based metrics were predominantly used to obtain accuracy outcomes (54%). Conclusions: The results from this review can help inform future research and practical interventions in an attempt to measure and optimise soccer kicking performance. However, given the risk of bias and a relative lack of strong evidence, caution is required when applying some of the current findings in practice. PROSPERO ID: CRD42018096942. [ABSTRACT FROM AUTHOR]

Core muscle function is considered a risk factor for low back pain appearance in dancers. The purpose of this study was to examine the transversus abdominis and lumbar multifidus thickness among Argentine Tango dancers in different functional dance positions. A secondary purpose was to compare muscle thickness at rest and contraction between dancers and untrained participants. Ten trained dancers and ten untrained women aged 33.8 ± 6.09 years participated in this study. Using ultrasonography, the transversus abdominis and lumbar multifidus muscle thickness were measured at rest and during contraction in three different dance positions: Basic in Open embrace, Basic in Close embrace, and Volcada. The results showed a significant increase in muscle thickness during contraction compared to thickness at rest for both muscles (p < 0.05). The group of dancers showed a greater transversus abdominis thickness than the untrained group (p < 0.05). Further, transversus abdominal thickness progressively increased from Basic in Open embrace to Basic in Close embrace position, as well as from Basic in Close embrace to Volcada position in dancers (p < 0.05), while fewer changes between positions were found for the untrained group. Multifidus muscle thickness also differed between positions, but no group differences were observed (p > 0.05). Training exercises in these Argentine Tango positions may be beneficial for the performance and prevention of low back pain, especially in Argentine Tango dancers. [ABSTRACT FROM AUTHOR]

Aim: The purpose of the present study was to establish which type of exercise is optimal for Rectus Abdominis (RA) muscle, by measuring thickness and length changes using the extended field of view ultrasonography (EFOV US) during different conditions. The second purpose was to estimate the reliability of EFOV US as a muscle morphology assessment tool.Material and Methods: Segmental muscle thickness and length of 11 young healthy adults was assessed during 1) rest and isometric 2) trunk lifting, 3) leg lifting and 4) combined trunk and leg lifting exercises with the use of EFOV US.Results: RA muscle thickness was significantly greater during exercises compared to rest (p<0.05). It was also observed that proximal and proximal-middle segments showed significantly less thickness and length compared to distal-middle and distal segments (p<0.05). Even though no differences in thickness were observed between the exercises, leg lifting and combined trunk and leg lifting exercises affected more the distal segment of RA muscle (p<0.05). Moreover, no significant differences in length between exercises was found (p>0.05). Further, EFOV US displayed excellent reliability as the ICC values ranged from 0.82 to 0.97.Conclusions: According to our observations it seems that exercises that induce lifting of the legs might be more effective for the distal parts of RA muscle. EFOV appears to be a reliable diagnostic tool for measuring RA muscle thickness during rest and contracting states. [ABSTRACT FROM AUTHOR]

Bridging exercises with abdominal hollowing are often used as a regimen for improving spinal stability. Lately, this type of training has become very popular among elite athletes, creating a need for more demanding exercises. The purpose of this study was to investigate whether the use of additional external resistance is beneficial for abdominal muscle recruitment during bridge exercise. Tissue movement of the transversus abdominis (TrA) and the rectus abdominis (RA) was recorded with the use of two synchronized ultrasonic devices, in 20 healthy college students. From the hook-lying position participants were examined in eight different exercise conditions: a) rest, b) abdominal drawing-in maneuver (ADIM), c) bridge, d) bridge- ADIM, e) bridge with 10KG, f) bridge- ADIM with 10KG, g) bridge with 20KG and h) bridge-ADIM with 20KG. Analysis of variance (ANOVA) showed a statistically significant increase in TrA thickness when performing the bridge exercise combined with ADIM compared to rest mode (p < .05). RA thickness decreased when the ADIM was performed, compared to rest (p < 0.05). No significant difference in TrA and RA thickness when exercising with and without external resistance was observed (p > 0.05). The main outcome of this study was that external loading provided some extra level of difficulty, yet it was not beneficial for abdominal muscle recruitment, when performing a supine bridge exercise. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of adding the integrated neuromuscular inhibition technique (INIT) to therapeutic exercise (TE) in individuals with chronic mechanical neck pain (CMNP). In this 34-week, assessor-blind randomized controlled trial, 40 participants (men and women) with CMNP with active or latent myofascial trigger points on the neck muscles were divided into 2 groups. The participants followed 4 treatments per week for 10 weeks. The intervention group followed a TE program in combination with the INIT, whereas the control group followed the same program without the INIT. Both protocols were applied by physiotherapists. Pain, disability, pressure pain threshold, active range of motion, and health-related quality of life were evaluated before, during, and after the intervention, whereas patients were followed for 6 months after completion of treatment. Repeated-measures ANOVA was applied. Both groups showed a significant improvement in all dependent measures after the intervention (P <.05). However, the intervention group showed greater improvement in the visual analog scale and neck disability index score, in the neck muscles pressure pain threshold, in the range of motion, and in the 36-Item Short Form Health Survey score, than the control group. In many of the above variables this improvement was seen from the second week and was maintained for 6 months after the intervention. The results of this preliminary study suggest that the addition of the INIT to a TE program had a positive effect on pain, functionality, and the quality of life in individuals with CMNP. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the differences in muscle architecture during isometric tests between children and adults. Eight boys (age= 11.2 ± 0.26 years) and eight men (age= 22.3 ± 2.01 years) performed plantar flexion isometric efforts at angles of -15°, 0°, 15° at 0%, 40%, 60%, 80% of MVC. Analysis of variance tests indicated that adults showed greater fascicle length from rest to 80% of MVC (p < .05), greater pennation angle at 80% and 100% of MVC (p < .05) and greater aponeuroses displacement at levels of effort greater than 60% of MVC (p < .05). These differences observed in MG would appear to favor better utilization of the force-length and the force-velocity relationships, of the muscle in adults compared with children. [ABSTRACT FROM AUTHOR]

Core stability exercises are regular part of exercise programs for asymptomatic individuals across ages. The purpose of this study was to examine deep abdominal and multifidus muscle thickness in children and adults and to determine reliability of the rehabilitative ultrasound (RUSI) imaging. Transversus abdominis and lumbar multifidus thickness at rest and during core stability exercise were examined in pre-pubertal children (N = 23), adolescents (N = 20), young adults (N = 21) and middle-aged adults (N = 22). Thirty-nine participants were re-tested one week after to establish reliability. Muscle thickness at rest was lower in children and adolescents compared with young and middle-aged adults (p < 0.008). Young adults displayed the highest relative transversus abdominis thickness upon contraction (p < 0.008). Lumbar multfidus contraction thickness was greater in young-adults than middle-aged adults and pre-pubertal children (p < 0.008), but it was similar between young-adults and adolescents (p > 0.008). Reliability was high for both muscles (ICC3,3 = 0.76 - 0.99). The age-related differences in muscle thickness indicate that core stability exercises may be beneficial for children and middle-aged adults. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether the application of the integrated neuromuscular inhibition technique (INIT) combined with therapeutic exercise (TE) can provide faster and greater improvement in maximum isometric strength and isometric endurance of the neck muscles in patients with chronic mechanical neck pain (CMNP). In this 10-week, single-blind clinical trial, 40 participants (men and women) with CMNP were divided into two groups. The intervention group (IG) followed a TE program in combination with the INIT, while the control group (CG) followed the same TE program without the INIT technique. Changes in maximum isometric strength and isometric endurance of the neck muscles were evaluated before, during, and after the intervention, with follow-up measurements taken at 1, 3, and 6 months after the intervention. Analysis of variance with repeated measures was applied. Both groups showed a significant improvement in all dependent measures after the intervention (p <.05). These changes were maintained for both groups 6 months after the intervention. However, the IG showed a greater improvement in the maximum isometric strength of neck flexion and an improved craniocervical flexion test score compared with the CG. The combination of TE and INIT had a positive effect on neck muscle strength and endurance in individuals suffering from CMNP as compared with TE alone. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pilates programs are widely used as a form of regular exercise in a broad range of populations investigating their effectiveness for chronic low back pain (CLBP) treatment. OBJECTIVE: The aim of this study was to compare the effects of a Pilates program and a trunk strengthening exercise program on functional disability and health-related quality of life (HRQOL) in women with nonspecific CLBP. METHODS: A total of 101 volunteer women with CLBP provided data with a 3-month follow-up. They were randomized to either a Pilates (n = 37), trunk strengthening exercise (n = 36) or a control group (n = 28), exercising for a period of 8 weeks, three times a week. Data were collected on HRQOL using the Short-Form 36 Health Survey (SF-36v2), and functional disability using the Roland Morris Disability Questionnaire prior to program initiation, mid-intervention, immediately after program termination, and three months post-intervention. RESULTS: The Pilates participants reported greater improvements on self-reported functional disability and HRQOL compared with participants in the trunk strengthening exercise and control groups (p < 0.05). The effects were retained for a period of three months after program termination for the Pilates group and to a lesser extent for the trunk strengthening exercise group. CONCLUSIONS: An 8-week Pilates program improved HRQOL and reduced functional disability more than either a trunk strengthening exercise program or controls among women with CLBP. [ABSTRACT FROM AUTHOR]

The article presents information on a study which analyzes the effects of a 10-week resistance exercise program on kick biomechanics and muscle strength in soccer players. The study included twenty male amateur soccer players who followed a resistance exercise program mainly for the lower limb muscles, and measured maximal instep kick kinematics, electromyography, and ground reaction forces (GRFs). The methods and results of the study are also discussed.

The article discusses research which was conducted to compare the effects an Olympic weightlifting (OL) and traditional weight (TW) training program had on muscle coactivation around the knee joint during vertical jump tests. Researchers evaluated 26 men. They found that the Olympic weightlifting improves jump performance via a constant knee muscle coactivation index, whereas the traditional weight training caused an increased coactivation index, probably to enhance joint stability.

The activity of the transverse abdominal (TrA) muscle affects the stabilization of the trunk. It is known that after a stroke, people experience problems in performing daily activities. The purpose of this study was to examine whether there are differences in the transversus abdominal thickness between the two sides of the body in individuals with hemiparesis and controls. Eight patients with hemiparesis and nine controls matched for age and body mass index were examined by musculoskeletal ultrasound in four conditions: a) At rest, b) abdominal hollowing maneuver from the supine position, c) bridge, and d) abdominal hollowing maneuver from the bridge position. In each of the above conditions, the symmetry index was calculated as the absolute value of the difference in thickness between the two sides. Analysis of variance showed a lower TrA thickness at rest and exercise in patients compared to the control group (p < 0.05). Further, patients showed a lower contraction thickness ratio during exercise compared to controls (p < 0.05). The absolute symmetry of the TrA thickness was 12.59 ± 6.43% to 19.31 ± 10.43% in patients and it was significantly greater than the control group (3.01 ± 2.47% to 4.47 ± 2.87%). According to the above results, it seems that transverse abdominal activation exercises are particularly useful for improving the stability of patients with hemiparesis, as long as they are located and adapted to the deficit of each patient. [ABSTRACT FROM AUTHOR]