Lifting Strength Research Articles

Functional physical training improves women’s military occupational performance

The U.S. Armed Forces have recently approved full integration of women into combat roles. Physical fitness demands for executing Military Occupational Specialties (MOS) are substantial; thus lifting and load carriage capability improvements are desirable. ObjectivesTo determine if a specially-designed physical conditioning program could lessen the gap between the performance of male and female Soldiers in lifting and load carriage and thereby enable women to meet the requirements of most, if not all, Army MOSs. MethodsForty women participated in a 24-week physical training program, which included resistance training, long-distance running, backpacking, and specialized drills. Pre- and post-tests of occupational and physical performance measures were conducted before and after training. Repeated measures analysis of variance were used to determine statistically significant differences among the pre-, mid- and posttests. ResultsWomen increased maximal occupational lifting strength 12–20 kg, added 9–34 repetitions in lifting endurance, increased 0.23 m in jumping performance, added 46 repetitions in local muscular endurance, and decreased load carriage for time by 3.7–8.6 min. Women scored within 82–94% of untrained male scores for aerobic capacity and muscular endurance after training. ConclusionWomen’s ability to perform physically-demanding military occupational tasks was significantly improved following 6 months of concurrent training, with emphasis on load carriage and lifting. The percentage of women that qualified for current “heavy” and “very heavy” MOSs was initially 24%, but increased to 78% after training. A resistance training program of 6+ months can adequately prepare women for “heavy” to “very heavy” MOS’s.

Functional Capacity Evaluation in Upper Limb Reduction Deficiency and Amputation: Development and Pilot Testing

Purpose To develop and pilot test a functional capacity evaluation (FCE) for individuals with upper limb absence (ULA) due to reduction deficiency or amputation, and to examine the relationship between FCE results and presence of musculoskeletal complaints (MSC). Method Five tests (overhead lifting, overhead working, repetitive reaching, fingertip dexterity, and handgrip strength) were selected and adapted if necessary. The newly developed FCE, called FCE-One-Handed (FCE-OH), was pilot tested in 20 adults individuals with ULA, and 20 matched controls. MSC were assessed via a questionnaire. Results Adaptations were considered necessary for all tests, except the handgrip strength test. The repetitive overhead lifting test of the non-affected limb was added. On the overhead lifting test, individuals with above-elbow ULA (ten males), performed similar to controls using one hand. When lifting bimanually using the prosthesis, a trend for lower lifting capacity of individuals with below-elbow ULA (seven males, three females) was observed compared to controls. On the overhead working test, individuals with above-elbow ULA performed worse compared to controls. Other tests showed no significant differences between groups. Relationships between FCE results and presence of MSC were non-significant. Conclusion The FCE-OH can be used to test functional capacity of one-handed individuals. Individuals with ULA generally showed similar functional capacity as two-handed individuals. FCE results were not related to MSC. It was discussed that a higher physical load on the non-affected limb might reflect a relative deficit of functional capacity.

Relationship between leg and back strength with inter-joint coordination of females during lifting

The role of strength and fatigue in the lifting technique is not very clear, especially with regards to inter-joint coordination. We examined the relationships between muscle strength and endurance with inter-joint coordination of the knee-hip (KH) and hip-back (HB) during a lifting task performed until exhaustion. Thirteen healthy females were recruited to participate in the study. Significant negative correlations were found between HB maximum relative phase angle and leg lifting strength (r = −0.805), knee extensor strength (r = −0.705), knee flexor strength (r = −0.633), back extensor strength (r = −0.593) and back flexor strength (r = −0.596). The greater the strength of these muscles, the more synchronized the hip-back inter-joint coordination. However, no significant relationships were found with endurance test performance. Moreover, although the lifting task induced muscle fatigue, there were no significant fatigue-induced changes in lifting coordination.

Reliability of New Methods to Quantify Forearm Torque and Lifting Strength

Objective/Hypothesis: Forceful forearm rotation and lifting strength are important aspects of upper extremity function. Yet they are rarely assessed in relation to wrist and forearm pathologies, or their treatments. Absence of reliable methods that are easy to use might be one reason for this discrepancy. We designed 2 new procedures to quantify forearm torque and lifting strength in a clinical setting. The objective of this study was to determine the intra- and interrater reliability of these methods. Materials and Methods: We used 2 commercially available dynamometers, the digital Baseline wrist dynamometer and the Kern hanging scale, to develop 2 procedures to measure forearm torque and lifting strength. Two assessors used the new techniques to test 15 healthy volunteers, 10 females and 5 males. Each assessor measured each participant on 3 occasions. Torque was tested for supination and pronation. Lifting strength was tested in 3 forearm positions, supinated, pronated, and neutral position. Analysis of reliability was performed using intraclass correlation coefficients (ICC), with 95% confidence intervals. As raters were fixed ICC model 3 was used with single measurements to determine consistency in agreement. Results: Torque: The intrarater reliability coefficients for test-retest observed for the Baseline dynamometer were for both raters between 0.96 and 0.97 for supination and 0.93 and 0.97 for pronation. There were no differences between the raters ( P < .001). Lifting strength: The intrarater ICCs for the different forearm positions were nearly the same for both investigators (0.95-0.99) and similar values were noted for the interrater comparisons (0.95-0.98). Conclusions: Both the Baseline and Kern dynamometers demonstrated excellent intra- and interrater repeatability. The quality of measurements performed with our new methods is sufficient for future studies of forearm torque and lifting strength. Simple, yet reliable methods to quantify torque and lifting strength in a clinical setting have the potential to improve evaluations of wrist and forearm disorders as well as their treatments.

Effect of Binders on Preparation of High Temperature Rigid Thermal Insulation Materials

With the development of ultra high temperature rigid heat insulation materials in the space field, it is an important strategic significance to prepare and research insulation materials of 1500°C high temperature. In our paper, the material was achieved through the process of wet suction filter forming and high temperature heat treatment, during which the high temperature alumina fiber was used as main ingredient. The fiber binder directly influences the mechanical and thermal properties of the material, and our samples were prepared using boron carbide and silicon carbide (both), borosilicate glass, alumina sol and aluminum dihydrogen phosphate as binder, respectively. The results show that borosilicate glass was the best one. Coefficient of thermal conductivity at 1000°C, lift strength and plane direction compression strength (10% compression) of the high temperature material were 0.12 W/mK, 0.35 MPa, and 1.1 MPa, respectively.

Lifting strength in two-person teamwork

This study examined the effects of lifting range, hand-to-toe distance, and lifting direction on single-person lifting strengths and two-person teamwork lifting strengths. Six healthy males and seven healthy females participated in this study. Two-person teamwork lifting strengths were examined in both strength-matched and strength-unmatched groups. Our results showed that lifting strength significantly decreased with increasing lifting range or hand-to-toe distance. However, lifting strengths were not affected by lifting direction. Teamwork lifting strength did not conform to the law of additivity for both strength-matched and strength-unmatched groups. In general, teamwork lifting strength was dictated by the weaker of the two members, implying that weaker members might be exposed to a higher potential danger in teamwork exertions. To avoid such overexertion in teamwork, members with significantly different strength ability should not be assigned to the same team.

Lift performance and lumbar loading in standing and seated lifts

This study investigated the effect of posture on lifting performance. Twenty-three male soldiers lifted a loaded box onto a platform in standing and seated postures to determine their maximum lift capacity and maximum acceptable lift. Lift performance, trunk kinematics, lumbar loads, anthropometric and strength data were recorded. There was a significant main effect for lift effort but not for posture or the interaction. Effect sizes showed that lumbar compression forces did not differ between postures at lift initiation (Standing 5566.2 ± 627.8 N; Seated 5584.0 ± 16.0) but were higher in the standing posture (4045.7 ± 408.3 N) when compared with the seated posture (3655.8 ± 225.7 N) at lift completion. Anterior shear forces were higher in the standing posture at both lift initiation (Standing 519.4 ± 104.4 N; Seated 224.2 ± 9.4 N) and completion (Standing 183.3 ± 62.5 N; Seated 71.0 ± 24.2 N) and may have been a result of increased trunk flexion and a larger horizontal distance of the mass from the L5-S1 joint.Practitioner Summary: Differences between lift performance and lumbar forces in standing and seated lifts are unclear. Using a with-in subjects repeated measures design, we found no difference in lifted mass or lumbar compression force at lift initiation between standing and seated lifts.

Correspondence Between Physical Self-Concept and Participation in, and Fitness Change After, Biweekly Body Conditioning Classes in Sedentary Women.

Aasa, U, Paulin, J, and Madison, G. Correspondence between physical self-concept and participation in, and fitness change after, biweekly body conditioning classes in sedentary women. J Strength Cond Res 31(2): 451-461, 2017-The aims of the study were (a) to investigate the effects of participation in low impact body conditioning classes on physical fitness in sedentary women at different ages and (b) to examine the correspondence between physical self-concept and participation in, and fitness change after, the participation. Ninety-two sedentary women (mean age 44.2 years) participated in 11 weeks of biweekly classes that included cardiovascular, strength, core, endurance, and mobility exercises, all performed in synchrony with music. Cardiorespiratory fitness, maximal lifting strength, mobility, and balance tests were performed before and after the exercise period and the short-form of the Physical Self-Description Questionnaire (PSDQ-S) was completed. Zero-order Spearman correlation analyses showed that women who rated the PSDQ-S dimension sport competence higher participated in a larger number of sessions (rs = 0.24, p = 0.040). At posttests, all participants had increased their balance, the participants aged 20-34 years had increased their lifting strength, and the participants aged 35-65 years had increased their cardiorespiratory fitness and mobility. Most PSDQ-S dimensions did not affect performance change, but the perception of being physically active was related to increased cardiovascular fitness. We conclude that women with a sedentary lifestyle who wish to increase their physical capacity benefit from music exercise and that inquiries about perceived sport competence and physical activity can improve recommendations made by strength and conditioning professionals.

Effects of the Naturally Occurring Parasitic NematodeChondronema passaliLeidy on Lifting Strength and Captivity-Related Body Mass Patterns in the Horned Passalus Beetle,Odontotaenius disjunctus(Illiger) (Coleoptera: Passalidae)

Abstract Parasites are ubiquitous among insects and well-studied, but knowledge of their full range of host effects is not complete, especially concerning their impact on physical performance of hosts. The horned passalus beetle, Odontotaenius disjunctus (Illiger), in the USA is frequently parasitized by Chondronema passali Leidy, a nematode that can number in the thousands within the hemocoel. We performed an experiment that examined the effects of this parasite on a key performance metric, lifting strength, which should be important during fighting. We assessed beetle lifting strength using a vertically-mounted force gauge, as well as their body mass. At the end of the experiment, we dissected the beetles to determine parasite status and gender. The average beetle (1–2 g each) lifted between 300 and 400 g during the trials. Though the final sample size of non-parasitized beetles was small (n = 8), our results showed parasitized beetles tended to lift 17% less weight than non-parasitized beetles, and thi...

The Effectiveness of Basic Military Training To Improve Functional Lifting Strength in New Recruits.

Australian Army recruits are required to meet the incumbent baseline physical employment standards (PES) during basic military training. A box lift and place (BLP) assessment is included in the PES, and it assesses the ability to perform essential muscular strength tasks. Therefore, basic military training must provide sufficient training stimulus to enable recruits to achieve the baseline BLP standard. A study was undertaken to investigate changes in the performance of 1-repetition maximum BLP in male (n = 154; age, 21.4 years) and female (n = 20; age, 23.1 years) recruits over the first 8 weeks of a 12-week basic military training course. Both male and female recruits showed modest improvements (2.2 ± 5.9 kg and 3.0 ± 3.1 kg, respectively; p ≤ 0.05) in maximal BLP performance, and there were no differences between genders. The female recruits showed greater relative improvements compared with the male recruits (14.7 ± 7.8% vs. 6.5 ± 2.3%). Despite the modest improvements in BLP performance, 70% of female and 100% of male recruits achieved the baseline BLP standard (25 kg) during week 8. The 30% failure rate for female recruits, however, suggests that the basic training program should be improved. A training program that yields greater gains in muscular strength would likely increase female recruit BLP pass rates. Augmented muscular strength would also likely increase the number of recruits capable of achieving higher BLP standards for more physically demanding employment categories. A training program that yields greater improvements in muscular strength may also enable lower entry standards, thereby increasing the recruit pool.

English

This study assessed the effects of progressive resistance exercise programmes on self-reported health related quality of life, body composition and muscle strength among patients with HIV. Twenty-nine men with HIV were randomly assigned to progressive resistance exercise programme using elastic band (PRE group) (n=14) or resistance exercise programme without elastic band (comparative group) (n=15). Both groups underwent exercise programmes for 12 weeks. Selfreported health related quality of life, body compositions and isometric shoulder lift strength were assessed at baseline and at week 12. Ten and nine men in the intervention and comparative groups, respectively, completed the 12-week programme. Participants in the comparative group showed significant improvements in the domain of mental health (p<0.05). No significant changes in all body composition parameters were found in both groups with time. Both groups showed significant improvements in peak and average shoulder lift strength (intervention, p=0.001; p=0.001; control, p=0.008; p=0.016). Progressive resistance exercise programmes significantly improves shoulder lift strength, showed positive effects on self-reported health related quality of life scores among patients with HIV.

Nutritional status and the gonadotrophic response to a polar expedition

Polar expeditions have been associated with changes in the hypothalamic-pituitary-testicular axis consistent with central hypogonadism (i.e., decreased testosterone, luteinising hormone (LH), and follicle stimulating hormone (FSH)). These changes are typically associated with body mass loss. Our aim was to evaluate whether maintenance of body mass during a polar expedition could mitigate against the development of central hypogonadism. Male participants (n = 22) from a 42-day expedition (British Services Antarctic Expedition 2012) volunteered to take part in the study. Body mass, body composition, and strength data were recorded pre- and postexpedition in addition to assessment of serum testosterone, LH, FSH, thyroid hormones, insulin-like growth factor 1 (IGF-1), and trace elements. Energy provision and energy expenditure were assessed at mid- and end-expedition. Daily energy provision was 6335 ± 149 kcal·day(-1). Estimated energy expenditure midexpedition was 5783 ± 1690 kcal·day(-1). Body mass and percentage body fat did not change between pre- and postexpedition. Total testosterone (nmol·L(-1)) (14.0 ± 4.9 vs. 17.3 ± 4.0, p = 0.006), calculated free testosterone (pmol·L(-1)) (288 ± 82 vs. 350 ± 70, p = 0.003), and sex hormone binding globulin (nmol·L(-1)) (33 ± 12 vs. 36 ± 11, p = 0.023) concentrations increased. LH and FSH remained unchanged. Thyroid stimulating hormone (TSH; IU·L(-1)) (2.1 ± 0.8 vs. 4.1 ± 2.1, p < 0.001) and free triiodothyronine (FT3; IU·L(-1)) (5.4 ± 0.4 vs. 6.1 ± 0.8, p < 0.001) increased while free thyroxine, IGF-1, and trace elements remained unchanged. Hand-grip strength was reduced postexpedition but static lift strength was maintained. Maintenance of body mass and nutritional status appeared to negate the central hypogonadism previously reported from polar expeditions. The elevated TSH and free FT3 were consistent with a previously reported "polar T3 syndrome".

Effects of Recreational Exercises on Children’s Anthorpometric Parameters and Their Level of Nutrition Knowledge

This paper was done with the intent of studying and reviewing the effects of summer schools on children's physical development and their level of knowledge about nutrition. In this study, the target segment was 200 volunteer children in age group of 10 to 12 years. Children's average age was 11. 12 year, average stature was 145.25 cm, average body weight was 44.57 kg, and average body-mass index was 21. Physical fitness and anthropometric evaluations and stature, body weight, vertical jump, anaerobic strength, grip strength, back and lift strength, body and 30 meters tests were implemented. A survey on students was conducted to collect information about student's nutritional habits and effects of their socio-economical situation on their nutritional habits. Besides, the summer schools adversely affect and cause hindrance in physical and mental development. However, the nutrition knowledge and habits should be constantly improved.

Effects of work experience and exertion height on static lifting strengths and lift strategies of experienced and novice female participants

In this study, 46 female experienced workers and inexperienced novices (23 each) were recruited to determine their maximum lifting strength at 15 exertion heights between 10 and 150 cm from the floor. The results revealed that the experienced workers' strengths at all 15 heights exhibited relatively little fluctuation, and were approximately 50–70 N lower than those of novices when heights were ≤50 cm. No differences in strengths were observed at 60–150 cm between the groups. The experienced workers tended to adopt a consistently deep squat at lower heights (≤50 cm) and a more erect posture with stiffened arms at higher heights (≥70 cm), resulting in lower L4/L5 disc compression forces and shoulder moments than in novices, respectively. In contrast to the lifting techniques adopted by experienced workers to effectively avoid overloading, the findings suggest that novice female workers who lack experience should be cautious and trained for performing lifting tasks. Relevance to industryThis study demonstrated that a discrepancy exists in lifting strengths between experienced and inexperienced female handlers at various heights. Findings from this study offers a reference for lifting task design and effective posture training on lifting, regarding the weighting of various shelves.

Task-specific neural adaptations to isoinertial resistance training.

This study aimed to delineate the contribution of adaptations in agonist, antagonist, and stabilizer muscle activation to changes in isometric and isoinertial lifting strength after short-term isoinertial resistance training (RT). Following familiarization, 45 men (23.2 ± 2.8 years) performed maximal isometric and isoinertial strength tests of the elbow flexors of their dominant arms before and after 3 weeks of isoinertial RT. During these tasks, surface electromyography (EMG) amplitude was recorded from the agonist (biceps brachii short and long heads), antagonist (triceps brachii lateral head), and stabilizer (anterior deltoid, pectoralis major) muscles and normalized to either Mmax (agonists) or to maximum EMG during relevant reference tasks (antagonist, stabilizers). After training, there was more than a twofold greater increase in training task-specific isoinertial than isometric strength (17% vs 7%). There were also task-specific adaptations in agonist EMG, with greater increases during the isoinertial than isometric strength task [analysis of variance (ANOVA), training × task, P = 0.005]. A novel finding of this study was that training increased stabilizer muscle activation during all the elbow flexion strength tasks (P < 0.001), although these were not task-specific training effects. RT elicited specific neural adaptations to the training task that appeared to explain the greater increase in isoinertial than isometric strength.

Head lifting strength is associated with dysphagia and malnutrition in frail older adults

The purpose of the present study was to assess the association between head lifting strength, dysphagia and malnutrition in frail older adults. A cross-sectional study was carried out in 386 frail older adults aged 65 years and older with dysphagia or suspected dysphagia. Head lifting strength was assessed by the Medical Research Council score. The severity of swallowing and nutritional status was evaluated using the Dysphagia Severity Scale and the Mini-Nutritional Assessment Short Form, respectively. Univariate and logistic regression analyses were applied to examine the associations between head lifting strength, dysphagia and malnutrition. There were 129 men and 257 women. The mean age was 83 years. The median Barthel Index score was 30 (interquartile range 5-65). A total of 189 (49%) older adults could independently lift their head. Based on the Dysphagia Severity Scale, 79 participants had no dysphagia, 138 had dysphagia without aspiration and 169 had dysphagia with aspiration. The Mini-Nutritional Assessment Short Form showed that 175 older adults were malnourished, 171 were at risk for malnutrition and 40 had a normal nutritional status. The Medical Research Council score in men was higher compared with women. Head lifting strength was significantly correlated with age (r = -0.256), the Barthel Index (r = 0.540), the Dysphagia Severity Scale (r = 0.458) and the Mini-Nutritional Assessment Short Form (r = 0.331). In logistic regression analysis, the Medical Research Council score was independently associated with both dysphagia with aspiration and malnutrition. Head lifting strength is associated with dysphagia with aspiration and malnutrition in frail older adults.

Physiological and biomechanical responses to a prolonged repetitive asymmetric lifting activity

This study investigated the effects of a prolonged repetitive asymmetric lifting task on behavioural adaptations during repetitive lifting activity, measures of tissue oxygenation and spine kinematics. Seventeen volunteers repeatedly lifted a box, normalised to 15% of the participant's maximum lifting strength, at the rate of 10 lifts/min for a period of 60 min. The lifts originated in front of the participants at ankle level and terminated on their left side at waist level. Overall, perceived workload increased during the repetitive lifting task. Erector spinae oxygenation levels, assessed using near-infrared spectroscopy, decreased significantly over time. Behavioural changes observed during the repetitive lifting task included increases in the amount of forward bending, the extension velocity and the lateral bending velocity, and a reduced lateral bending moment on the spine. These changes, with the exception of the reduced lateral bending moment, are associated with increased risk of low back disorder.

Sex Differences in Static Lifting Strengths at Full Range Exertion Heights in a Young Taiwanese Sample

This study evaluated sex differences in static lifting strengths (LS) at various exertion heights. Healthy adult young men (n=50; M age=23.4 yr., SD=2.3) and women (n=50; M age=22.5 yr., SD=2.8) were used as participants, and their static lifting strengths were measured at various heights (10 to 150 cm, in increments of 10 cm). Repeated measures ANOVA indicated that the strength profiles were significantly different. When the exerting height was less than or equal to 80 cm, the strengths of women were approximately two-thirds that of the men. Participants adopted a nearly erect posture at above 80 cm, and the weakness of women's upper extremities and disadvantageous posture were directly reflected in reduced strength values relative to men. One potential implication is that, because of the relatively lower isometric lifting strength for young Taiwanese women, caution should be exercised in the weight limit when lifting heights above the hip level, especially when above the shoulder level.

A Comparison of the Effects of 6 Weeks of Traditional Resistance Training, Plyometric Training, and Complex Training on Measures of Strength and Anthropometrics

Complex training (CT; alternating between heavy and lighter load resistance exercises with similar movement patterns within an exercise session) is a form of training that may potentially bring about a state of postactivation potentiation, resulting in increased dynamic power (Pmax) and rate of force development during the lighter load exercise. Such a method may be more effective than either modality, independently for developing strength. The purpose of this research was to compare the effects of resistance training (RT), plyometric training (PT), and CT on lower body strength and anthropometrics. Thirty recreationally trained college-aged men were trained using 1 of 3 methods: resistance, plyometric, or complex twice weekly for 6 weeks. The participants were tested pre, mid, and post to assess back squat strength, Romanian dead lift (RDL) strength, standing calf raise (SCR) strength, quadriceps girth, triceps surae girth, body mass, and body fat percentage. Diet was not controlled during this study. Statistical measures revealed a significant increase for squat strength (p = 0.000), RDL strength (p = 0.000), and SCR strength (p = 0.000) for all groups pre to post, with no differences between groups. There was also a main effect for time for girth measures of the quadriceps muscle group (p = 0.001), the triceps surae muscle group (p = 0.001), and body mass (p = 0.001; post hoc revealed no significant difference). There were main effects for time and group × time interactions for fat-free mass % (RT: p = 0.031; PT: p = 0.000). The results suggest that CT mirrors benefits seen with traditional RT or PT. Moreover, CT revealed no decrement in strength and anthropometric values and appears to be a viable training modality.

Effects of a daily mixed nutritional supplement on physical performance, body composition, and circulating anabolic hormones during 8 weeks of arduous military training

The aim of this work was to investigate the effect of a daily mixed nutritional supplement upon body composition, physical performance, and circulating anabolic hormones in soldiers undergoing arduous training. Thirty males received either a habitual diet alone (CON, n = 15) or with the addition of a daily mixed supplement (SUP, n = 15) of ∼5.1 MJ·d⁻¹ during 8 weeks of training. Body composition (DEXA), maximal dynamic lift strength (MDLS), and vertical jump (VJ) were assessed, and resting blood samples were collected before and after training. Blood analysis included insulin-like growth factors (IGF-1, IGF BP-1, and IGF BP-3), testosterone, and cortisol. There were no group differences at baseline. Body mass loss (mean ± SD) (CON 5.0 ± 2.3, SUP 1.6 ± 1.5 kg), lean mass loss (CON 2.0 ± 1.5, SUP 0.7 ± 1.5 kg), and fat mass loss (CON 3.0 ± 1.6, SUP 0.9 ± 1.8 kg) were significantly blunted by SUP. CON experienced significant decrements in MDLS (14%), VJ (10%), and explosive leg power (11%) that were prevented by SUP. Military training significantly reduced circulating IGF-1 (28%), testosterone (19%), and the testosterone:cortisol ratio (24%) with no effect of SUP. Circulating IGF BP-1 concentration and cortisol remained unchanged throughout, although SUP abolished the significant decrease in circulating IGF BP-3 (20%) on CON. In conclusion, a daily mixed nutritional supplement attenuated decreases in body mass and lean mass and prevented the decrease in physical performance during an arduous military training program.