The objective of the study was to examine the effect of suspension training on muscle activation during performance of variations of the plank exercise. Twenty-one participants took part. All individuals completed 2 repetitions each of 4 different plank exercises that consisted of a floor based plank, or planks with arms suspended, feet suspended, or feet and arms suspended using a TRX Suspension System. During plank performance, muscle activation was recorded from rectus abdominis, external oblique, rectus femoris, and serratus anterior (SA) muscles using electromyography. All planks were performed for a total of 3 seconds. Resulting muscle activation data were amplitude normalized, and root mean square activation was then determined over the full 3 second duration of the exercise. A significant main effect of plank type was found for all muscles. Post hoc analysis and effect size examination indicated that abdominal muscle activation was higher in all suspended conditions compared to the floor based plank. The highest level of abdominal muscle activation occurred in the arms suspended and arms/feet suspended conditions, which did not differ from one another. Rectus femoris activation was greatest during the arms suspended condition, whereas SA activity peaked during normal and feet suspended planks. These results indicate that suspension training as performed in this study seems to be an effective means of increasing muscle activation during the plank exercise. Contrary to expectations, the additional instability created by suspending both the arms and feet did not result in any additional abdominal muscle activation. These findings have implications in prescription and progression of core muscle training programs.

Previous investigators have speculated that applying additional external load throughout the eccentric phase of the jumping movement could amplify the stretch-shortening cycle mechanism and modulate jumping performance and jump exercise intensity. The aims of this study, therefore, were to determine the effect of increased eccentric phase loading, as delivered using an elastic device, on drop jumps (DJs) performed from different drop heights. Of specific interest were changes in (a) the kinetics; eccentric and concentric impulse, rate of force development (RFD), concentric velocity and (b) the electromyographic (EMG) activity of leg muscles. In a randomized repeated-measure study, 15 highly resistance trained male subjects performed DJs from 3 heights (20, 35, and 50 cm) under 3 different conditions: body weight only (free DJ) and with elastic bands providing downward force equivalent to 20% (+20% DJ) and 30% (+30% DJ) of body mass. All DJs were recorded using video and force plate data that were synchronized with EMG data. Results demonstrated that using additional tensile load during the airborne and eccentric phases of the DJ could enhance eccentric impulse (p = 0.042) and RFD (p < 0.001) and resulted in small to moderate effect size (ES) increases in quadriceps intergrated EMG across the eccentric phase (0.23 > ES > 0.51). The observed greater eccentric loading, however, did not immediately alter concentric kinetics and jump height nor did it alter muscle activation levels during this phase. The findings indicated that, in addition to the conventional technique of increasing drop height, using a tensile load during the airborne and eccentric phases of the DJ could further improve eccentric loading of DJs. As it has been suggested that eccentric impulse and RFD are indicators of DJ exercise intensity, these findings suggest that the loaded DJs, using additional elastic load, may be an effective technique for improving DJ exercise intensity without acute effects on the jumping performance and neuromuscular activation level in highly trained athletes.

No abstract

Roller massage (RM) has been reported to increase range-of-motion (ROM) without subsequent performance decrements. However, the effects of different rolling forces have not been examined. The purpose of this study was to compare the effects of sham (RMsham), moderate (RMmod) and high (RMhigh) RM forces, calculated relative to the individuals' pain perception, on ROM, strength and jump parameters. Sixteen healthy individuals (27 ± 4 years) participated in this study. The intervention involved three 60-second quadriceps RM bouts with RMlow (3.9/10±0.64 rating of perceived pain{RPP}), RMmod (6.2/10±0.64 RPP) and RMhigh (8.2/10±0.44 RPP) pain conditions respectively. A within-subject design was used to assess dependent variables (active and passive knee flexion ROM, single-leg drop jump (DJ) height, DJ contact time, DJ performance index, maximum voluntary isometric contraction (MVIC) force, and force produced in the first 200 ms (F200) of the knee extensors and flexors). A two-way repeated measures analysis of variance (ANOVA) showed a main effect of testing time in active (p < 0.001, d = 2.54) and passive (p < 0.001, d = 3.22) ROM. Independent of the RM forces, active and passive ROM increased by 7.0% (p = 0.03, d = 2.25) and 15.4% (p < 0.001, d = 3.73) from pre- to post measures, respectively. DJ and MVIC parameters were unaffected from pre- to post-tests (p > 0.05, d = 0.33 - 0.84). RM can be efficiently used to increase ROM without substantial pain and without subsequent performance impairments.

Twelve patients were involved in a 3 month stimulation induced cycling programme at the Royal Perth Rehabilitation Hospital. A number of the patients were less than 1 year post injury, all except one had an incomplete injury, and most were receiving physiotherapy. All patients who completed the programme increased their time of cycling and, in all but one case, the exercise load, indicative of a local training effect. Significant improvements were found in voluntary isometric strength, stimulated isometric strength and stimulated isometric endurance of the quadriceps, muscle grading of the quadriceps and biceps femoris and the cross-sectional areas of the quadriceps and total thigh muscle. No change was found in voluntary isokinetic strength of the quadriceps. All patients with incomplete injuries reported improvements in the activities of daily living (ADL) after the programme. Bone mineral density (BMD) was examined in two patients, one less than 1 year post injury, and one greater than 4 years post injury. The programme of cycling did not restore BMD in the latter patient. However, while the former patient still displayed a reduced BMD after the programme, it is unknown whether this loss of bone was retarded. This needs further investigation. This study demonstrates the effectiveness of a combined physiotherapy/cycling programme in the rehabilitation of people with spinal injuries. To be successful this type of programme has to be incorporated into the rehabilitation process, as has been done at the Sir George Bedbrook Spinal Unit.

In the following study, the authors examine factors that explain citizen participation in crime prevention activities in Boston. Using survey data from a random sample, census data, and official crime and arrest data, the authors identified a wide range of individualand community-based indicators that could potentially explain citizen involvement in crime prevention. Findings revealed that citizen involvement in collective crime prevention does indeed vary by the risk level of a particular neighborhood, with high-risk neighborhoods demonstrating higher rates of involvement than low-to moderate-risk neighborhoods. The authors also found that the factors that explained citizen participation varied by the risk level of the neighborhood. Overall, this research demonstrated that in high-risk neighborhoods, citizen involvement in crime prevention activities is affected by the unique blend of personal, parochial, and public social control mechanisms operating in these areas.In 2003, approximately 3.2% of all U.S. residents (1 in 32 adults) were under some form of correctional control. Although the vast majority of these 6.9 million adult offenders were being controlled in the community, very little attention has been focused on the types of communities in which these offenders reside and the consequences of offender location for both offenders and communities. However, recent federal government reentry initiatives have begun to shed considerable light on this issue. Byrne and Taxman (2004), for example, report that more than half of the 600,000 inmates released from prison in 2002 were from five states (California, Florida, Illinois, New York, and Texas); in these states, most offenders are returning to a relatively small number of urban, high-risk neighborhoods. Even though 203 APRIL PATTAVINA:

No abstract

Middle-aged individuals may not respond in a similar manner as younger individuals. The study's objective was to examine the effect of static (SS) and dynamic stretching (DS) in young and middle-aged men on subsequent performance. Ten young (22 ± 1.4 years) and 8 middle-aged men (46.3 ± 6.5 years) participated in 3 conditions consisting of SS (4 × 30 s for right and left quadriceps, hamstrings, and plantar flexors), DS (8 × 30 s of bilateral butt kicks, walking lunges, and plantar flexors) and control. Dependent variables included sit and reach, hip extension flexibility, countermovement jump (CMJ) height, drop jump (DJ) height, static balance, reaction (RT) and movement time (MT). Measurements were taken pre-intervention, post- and 10 min post-intervention. A 3-way repeated measurement ANOVA revealed that the younger men had higher jump heights, faster RT and MT, and greater flexibility than the middle-aged men. DS significantly enhanced DJ (p = 0.04) and CMJ (p = 0.006) height compared with SS and control conditions. SS (p < 0.0001) and DS (p = 0.004) post-intervention sit and reach scores were significantly greater than pre-intervention scores. There were no significant differences between the SS and DS sit and reach scores. CMJ heights were impaired (p = 0.04) by SS. Conversely, DS post-intervention jump heights were significantly (p < 0.0001) higher than SS post-, control post-, and control 10 min post-intervention. SS-induced impairments and DS-induced enhancements of CMJ height were not affected by age. DS provided similar improvements in sit and reach scores as SS. DS is recommended as the most appropriate stretching routine prior to work or athletic performance for younger and middle-aged men.