Effect of Unstable Loads on Stabilizing Muscles and Bar Motion During the Bench Press.

ABSTRACT: Lawrence, MA, Ostrowski, SJ, Leib, DJ, and Carlson, LA. Effect of unstable loads on stabilizing muscles and bar motion during the bench press. J Strength Cond Res 35(2S): S120-S126, 2021-Unstable loads are anecdotally used to increase muscle stabilizer strength and utilization; however, there is little evidence to support these claims. Twelve male powerlifters (age 28.6 ± 5.2 years, body mass 105.6 ± 14.5 kg, lifting experience 9.8 ± 6.0 years, and bench press 5 repetition maximum [5RM] 133.6 ± 30.9 kg) pressed their 5RM in one stable condition with a standard barbell, and 3 unstable conditions using a flexible barbell with weights suspended from elastic bands. Mean integrated muscle activity for each repetition of the stabilizers and prime movers were measured. A Lyapunov exponent and sample entropy indicated unstable loads were less predictable and more variable in the superior/inferior direction, thus more challenging to control, despite decreased loads. The main finding was increased bicep activity in all unstable conditions (light bands and plates, +57%; mini bands and plates, +67%; and mini bands and kettlebells, +88%). Although less weight was used in the unstable 5RMs, most stabilizer muscle activity was not different between conditions, suggesting that the amount of weight used during unstable load training (up to 32.3% less load) may be limited by the ability of stabilizer muscles to control the load.

Zika Virus Testing Considerations: Lessons Learned from the First 80 Real-Time Reverse Transcription-PCR-Positive Cases Diagnosed in New York State.

The performance and interpretation of laboratory tests for Zika virus (ZKV) continue to be evaluated. Serology is cross-reactive, laborious, and frequently difficult to interpret, and serum was initially solely recommended for molecular diagnosis. ZKV testing was initiated in January 2016 in New York State for symptomatic patients, pregnant women, their infants, and patients with Guillain-Barré syndrome who had traveled to areas with ZKV transmission. Subsequently, eligibility was expanded to pregnant women with sexual partners with similar travel histories. Serum and urine collected within 4 weeks of symptom onset or within 6 weeks of travel were tested with real-time reverse transcription-PCR (RT-PCR) assays targeting the ZKV envelope and NS2B genes. In this review of lessons learned from the first 80 positive cases in NYS, ZKV RNA was detected in urine only in 50 patients, in serum only in 19 patients, and in both samples concurrently in 11 patients, with average viral loads in urine a log higher than those in serum. Among 93 positive samples from the 80 patients, 41 were positive on both gene assays, 52 were positive on the envelope only, and none were positive on the NS2B only. Of the 80 infected patients, test results for 74 (93%) would have defined their infection status as not detected or equivocal if the requirement for positive results from two assay targets (two-target-positive requirement) in the initial federal guidance to public health laboratories was enforced, if urine was not tested, or if the extended eligibility time for molecular testing was not implemented. These changes facilitated more extensive molecular diagnosis of ZKV, reducing reliance on time-consuming and potentially inconclusive serology.

Effect of an Unstable Load on Primary and Stabilizing Muscles During the Bench Press.

Ostrowski, SJ, Carlson, LA, and Lawrence, MA. Effect of an unstable load on primary and stabilizing muscles during the bench press. J Strength Cond Res 31(2): 430-434, 2017-Unstable resistance exercises are performed to increase activity of stabilizing muscles. The premise is that this increase in activity will yield greater strength gains than traditional resistance exercises. The purpose of this study was to determine if an unstable load increases muscle activity of stabilizing muscles during a bench press as compared with a standard bench press with a typical load. Fifteen resistance-trained males (age 24.2 ± 2.7 years, mass 84.8 ± 12.0 kg, height 1.77 ± 0.05 m, weight lifting experience 9.9 ± 3.4 years, and bench press 1 repetition maximum [1RM] 107.5 ± 25.9 kg) volunteered for this study. Subjects pressed 2 sets of 5 repetitions in both stable (75% 1RM) and unstable (60% 1RM) conditions using a standard barbell and a flexible Earthquake bar, respectively. Surface electromyography was used to detect muscle activity of primary movers (pectoralis major, anterior deltoid, and triceps) and stabilizing musculature (latissimus dorsi, middle and posterior deltoid, biceps brachii, and upper trapezius). Muscle activity was compared using a multivariate analysis of variance to determine significant (p ≤ 0.05) phase and condition differences. The right and left biceps and the left middle deltoid were significantly more active in the unstable condition. Some of the stabilizing muscles were found to be significantly more active in the unstable condition with 15% less weight. Therefore, bench pressing with an unstable load appears promising in activating stabilizing musculature compared with pressing a typical barbell.

Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation.

Lawrence, MA, Leib, DJ, Ostrowski, SJ, and Carlson, LA. Nonlinear analysis of an unstable bench press bar path and muscle activation. J Strength Cond Res 31(5): 1206-1211, 2017-Unstable resistance exercises are typically performed to improve the ability of stabilizing muscles to maintain joint integrity under a load. The purpose of this study was to examine the effects of an unstable load (as provided by a flexible barbell and a load suspended by elastic bands) on the bar path, the primary musculature, and stabilizing musculature while bench pressing using nonlinear analyses. Fifteen resistance-trained men (age 24.2 ± 2.7 years, mass 84.1 ± 12.0 kg, height 1.77 ± 0.05 m, 9.9 ± 3.4 years of lifting experience, and bench press 1 repetition maximum (RM) 107.5 ± 25.9 kg) volunteered for this study. Subjects pressed 2 sets of 5 repetitions in both stable (total load 75% 1RM) and unstable (total load 60% 1RM) conditions using a standard barbell and a flexible Earthquake bar, respectively. Surface electromyography was used to detect muscle activity of primary movers (pectoralis major, anterior deltoid, and triceps) and bar stabilizing musculature (latissimus dorsi, middle and posterior deltoid, biceps brachii, and upper trapezius). During the unstable condition, the bar moved in more ways and was less predictable in the mediolateral and anteroposterior directions. However, the muscle activation patterns of all muscles were more constrained with the unstable barbell. These findings suggest that the unstable condition was more challenging to control, but subjects controlled the instability by contracting their muscles in a more stable pattern or "staying tight" throughout the exercise.

An outbreak of equine botulism type A associated with feeding grass clippings.

In September 2010, an outbreak of type A botulism involved 4 horses in northern California that were fed grass clippings obtained from a nearby park. All 4 animals developed a progressive flaccid paralysis syndrome clinically consistent with exposure to preformed Clostridium botulinum neurotoxin (BoNT). Within 48 hr of consuming the grass clippings, all 4 horses showed marked cervical weakness (inability to raise their heads to a normal position) and died or were euthanized within 96 hr. One horse was submitted for diagnostic examination and subsequent necropsy. At necropsy, extensive edema was observed in areas of the nuchal ligament and inguinal fascia. A sample of the grass clippings tested positive for preformed BoNT type A by the mouse bioassay test. Emphasis should be placed on early case recognition, rapid initiation of treatment with the trivalent antitoxin product, and preventing exposure to BoNT in spoiled forages.

Packaging and shipping capabilities of New York State hospital laboratories: a 3-year drill assessment.

In a previous publication, we discussed the results of the 2006-2007 New York State (NYS) Hospital Laboratory Drill Series which emphasized the need for ongoing testing and evaluation of laboratory preparedness capabilities, particularly those required to support hospital functions during a public health emergency. In this paper, we will discuss how a followup drill series in 2007-2008 was implemented in an effort to re-assess the ability of NYS acute care hospital facilities to recognize and respond to a suspected bioterrorism, chemical terrorism or pandemic flu emergency specimen submission event. We will explain how the results of the follow-up drill series, when compared to those of the original exercise, warranted a statewide hospital laboratory preparedness drill held in 2009, focused solely on addressing the overarching deficiency of chemical terrorism (CT) specimen submission capabilities. Although drill results conclude that NYS acute care hospital facilities are much better prepared than 3 years ago to support hospital functions during a CT public health emergency event, they also highlight the continued need to improve competency.

Functional assessment of hospital laboratory packaging and shipping preparedness in New York State.

The 2006-2007 New York State (NYS) Hospital Laboratory Drill Series was implemented in order to test notification, referral and packaging and shipping (P&S) procedures at acute care hospital facilities (statewide, excluding New York City) that submit suspect bioterrorism (BT), chemical terrorism (CT), and/or pandemic influenza (Pan Flu) clinical specimens to the NYS Department of Health (DOH) Wadsworth Center for confirmatory testing. Results showed that 97% and 84% of hospital facilities had the ability to directly access the notification network and retrieve drill guidance, respectively. Most hospital laboratories (92%) demonstrated the ability to refer specimens to the Wadsworth Center laboratory. Evaluation of specimen submissions found that 68% of BT packages, 27% of Pan Flu packages, and 20% of CT packages arrived to the laboratory with no P&S deficiencies. It can be concluded that acute care hospital facilities in NYS are more prepared to refer and submit clinical specimens during a BT public health emergency than during a Pan Flu or CT emergency event.

Separate origins of hepatitis B virus surface antigen-negative foci and hepatocellular carcinomas in transgenic HBsAg (alb/psx) mice.

We have examined the development and transgene expression in liver lesions of transgenic mice bearing the hepatitis B surface antigen (HBsAg) gene of hepatitis B virus under the control of the albumin promoter (alb/psx) to study liver regeneration and hepatocellular carcinoma (HCC) associated with hepatitis B virus infection. Storage of the HBsAg in the endoplasmic reticulum precedes loss of liver cells and regenerative hyperplastic nodules that do not express HBsAg. Histological analysis indicated that HBsAg-negative foci and nodules arose from liver progenitor cells in the portal zone and lacked mRNA expression. Genomic DNA from eight of nine HBsAg-negative laser capture-excised liver foci showed loss of part of the alb/psx gene, whereas no loss of the actin gene was observed. The alb/psx DNA was intact in adjacent HBsAg-positive tissue. Sequencing of polymerase chain reaction products suggested that alterations in the HBsAg transgene in HBsAg-negative foci occurred via large-scale deletions as opposed to single-site mutations. Southern blot analysis of HCC from 2-year-old transgenic HBsAg mice, however, revealed an intact alb/psx gene. Thus, HBsAg-negative progenitor cells with deletions in the transgene appear to be responsible for compensatory regeneration of the liver, whereas HCCs arise from clonal expansion of hepatocytes with intact alb/psx transgenes.

Progression or resolution of coxsackievirus B4-induced pancreatitis: a genomic analysis.

Group B coxsackieviruses are associated with chronic inflammatory diseases of the pancreas, heart, and central nervous system. Chronic pancreatitis, which can develop from acute pancreatitis, is considered a premalignant disorder because it is a major risk factor for pancreatic cancer. To explore the genetic events underlying the progression of acute to chronic disease, a comparative analysis of global gene expression during coxsackievirus B4-induced acute and chronic pancreatitis was undertaken. A key feature of acute pancreatitis that resolved was tissue regeneration, which was accompanied by increased expression of genes involved in cell growth, inhibition of apoptosis, and embryogenesis and by increased division of acinar cells. Acute pancreatitis that progressed to chronic pancreatitis was characterized by lack of tissue repair, and the expression map highlighted genes involved in apoptosis, acinoductular metaplasia, remodeling of the extracellular matrix, and fibrosis. Furthermore, immune responses appeared skewed toward development of alternatively activated (M2) macrophages and T helper 2 (Th2) cells during disease that resolved and toward classically activated (M1) macrophages and Th1 cells during disease that progressed. Our hypothesis is that growth and differentiation signals coupled with the M2/Th2 milieu favor acinar cell proliferation, while diminished growth signals and the M1/Th1 milieu favor apoptosis of acinar cells and remodeling/proliferation of the extracellular matrix, resulting in fibrosis.

An Atypical Case of Mycobacterium bovis in a Cynomolgus Macaque (Macaca fascicularis) Imported From the Philippines.

An incidental case of Mycobacterium bovis was confirmed in a cynomolgus macaque from a shipment of 100 animals imported to the University of Southwestern Louisiana New Iberia Research Center from the Philippines. The macaque was euthanized 4 weeks into the quarantine period (October 1997) for failure to thrive and suspected melioidosis. Approximately 6 months later, on 9 March 1998, culture and antigenic probes from kidney tissues identified the etiologic agent as M. bovis. Five remaining cohort animals were euthanized after we obtained the results from the index case. Kidney tissues from two of the cohort animals were positive for M. avium. All animals had negative intradermal skin tests prior to euthanasia. All three animals positive for Mycobacterium were sero-negative for retroviruses. The unusual presentation of this case, coupled with the inability to detect disease by standard means, serves to emphasize the importance of follow-up examination and culture of tissues obtained from imported non-human primates.

Lead exposure from conventional and cottage lead smelting in Jamaica

A survey was conducted to determine the distribution and determinants of environmental and blood lead levels near a conventional and several cottage lead smelters and to assess the relationship between environmental and blood lead levels in a tropical developing-country setting. Fifty-eight households were studied in the Red Pond community, the site of the established smelter and several backyard smelters, and 21 households were studied in the adjacent, upwind Ebony Vale community in Saint Catherine Parish, Jamaica. Households were investigated, using questionnaires, soil and housedust lead measurements, and blood lead (PbB) measurements from 372 residents. Soil lead levels in Red Pond exceeded 500 parts per million (ppm) at 24 percent of household (maximum--18,600 ppm), compared to 0 percent in Ebony Vale (maximum 150 ppm). Geometric mean PbB levels >25 micrograms per deciliter (ug/dL), was more than twice that Ebony Vale in all age groups (p<0.0005). Within Red Pond, proximity to backyard smelters and to the conventional smelter were independent predictors of soil lead (p<0.05). Soil lead was the strongest predictors of PbB among Red Pond subjects under 12 years of age. The blood lead--Soil lead relationship in children differed from that reported in developed countries; blood lead levels were higher than expected for the household-specific soil lead levels that were observed. These data indicate that cottage lead smelters, like conventional ones, are a hazard for nearby residents and that children exposed to lead contamination in tropical, developing countries may be at higher risk for developing elevated blood levels than similarly-exposed children in developed countries (AU)

Blood lead and zinc protoporphyrin levels in donkeys and mules near a secondary lead smelter in Jamaica

During the course of an investigation into community lead poisoning near a secondary lead smelter in Jamaica, blood lead and zinc protoporphyrin levels were measured in 8 exposed and 6 (3 Jamaican, 3 US) unexposed donkeys and mules. The blood lead levels of 6 animals in the contaminated area ranged from 7.5 to 33 ug/d1 (mean=17.6 ug/d1), compared to 1.8 and 2.4 in unexposed Jamaican animals. More striking was the difference in zinc protoporphyrin levels; all 8 exposed donkeys and mules had values between 900 and 1890 ug/d1, compared with a range of 34-46 ug/d1 for 3 Jamaican control donkeys. These findings suggest that zinc protoporphyrin may be a useful method of screening for subclinical lead toxicity in equines (AU)

Lead poisoning among household members exposed to lead-acid battery repair shops in Kingston, Jamaica

To investigate the risk of lead poisoning among household members exposed to 'backyard' battery repair shops (BBRS) in Kingston, Jamaica, environmental and blood lead (PbB) were measured at 24 households (112 individuals) with a BBRS worker or located at a BBRS premises and at 18 neighbourhood control households (74 individuals). Elevated PbB (greater than or equal to 25 micrograms per decilitre [micrograms/dl]) was common among subjects of all ages living at BBRS premises, especially among children less than age 12, 43 percent of whom had PbB greater than 70 micrograms/dl. Potentially hazardous soil and house dust lead levels were also common at BBRS premises, where 84 percent of yards had soil lead levels above 500 parts per million (geometric mean 3388 parts per million [ppm] at BBRS premises households with a BBRS worker). Geometric mean blood and environmental lead levels were significantly lower at control households, where less than 10 percent of subjects in all age groups had elevated PbB (maximum 33 microgram/dl). Sharing a premises with a BBRS was a stronger determinant of household blood lead and environmental contamination than was the presence of a BBRS worker in a household. Blood lead levels were associated with soil and house dust lead levels in all age groups. We conclude that small battery repair shops, which have also been described in other developing countries, create a high lead poisoning risk for nearby residents (AU)