Simultaneous Upper- and Lower-Limb Postactivation Performance Enhancement After Clean and Jerk.

Studies on postactivation performance enhancement (PAPE) have used different exercises as a conditioning activity to investigate potentiation, but exclusively in upper limbs (UL) or lower (LL) limbs, or contralateral potentiation. A single exercise capable of inducing PAPE in both UL and LL is currently unknown. The present study explored the effect of the clean and jerk (C&J) as a conditioning activity for simultaneously producing PAPE interlimbs at the fourth, seventh, and 12th minutes postintervention. Twelve male weightlifters with 1-repetition maximum (1RM) in the C&J equivalent to ≥1.15 × body mass were randomly submitted to 2 experimental conditions (C&J and control [CON]). The C&J condition consisted of general warm-up (running on a treadmill and self-selected preparatory exercises) and 4 sets of 3 repetitions of C&J with 2 minutes between them (30%1RM, 50%1RM, 65%1RM, and 80%1RM) followed by a countermovement jump and a bench-press throw on a Smith machine after 4, 7, and 12 minutes, to measure the magnitude of PAPE in UL and LL. No previous exercise preceded countermovement-jump and bench-press-throw tests in the CON besides general warm-up. The main finding was that, regardless of time, the C&J resulted in greater height on countermovement jump and Smith machine bench-press throw when compared with the CON, presenting a similar effect size between UL and LL (34.6 [3.9] vs 33.4 [4.1] cm [+3.66%]; P = .038; effect size = 0.30 and 30.3 [4.7] vs 29.0 [5.1] cm [+4.44%]; P = .039; effect size = 0.26), respectively. Thus, C&J can be useful to produce PAPE simultaneously among members.

A cross-sectional analysis of the muscle strength, spinal shrinkage, and recovery during a working day of military police officers.

OBJECTIVE: Military personnel has a large prevalence of back pain, especially those involved in patrolling routines, as they wear heavy protective equipment. Patrolling includes long periods of sustaining the protective equipment in a sitting or in a motor vehicle (motorcycle or car). Thus, understanding spinal loading of military police officers after patrolling by car (CAR; n = 14), motorcycle (MOT; n = 14), and administrative (ADM; n = 14) routines is relevant to establish preventive strategies. METHODS: The torque of the trunk and working and anthropometric characteristics were assessed to explain spinal loading using stature variation measures. Precise stature measures were performed before and after a 6 h journey (LOSS) and 20 min after a resting posture (RECOV). The trunk extensor (PTE BM-1 ) and flexor (PTF BM-1 ) muscles' isometric peak torque were measured before the working journey. RESULTS: The LOSS was similar between CAR and MOT (4.8 and 5.8 mm, respectively) after 6 h of patrolling. The ADM presented the lowest LOSS (2.8 mm; P < .05). No changes in RECOV between groups were observed (P > .05). Vibration may explain the greater spinal loading involved in patrolling in comparison to the ADM. A GLM analysis revealed that BMI was the only explanatory factor for stature loss. No independent variables explained RECOV. The ability of the trunk muscles to produce force did not influence LOSS or RECOV. CONCLUSIONS: Military police officers involved in patrolling may require greater post-work periods and strategies designed to reduce the weight of the protective apparatus to dissipate spinal loading. The external load used in patrolling is a relevant spinal loading factor.

Immediate Effects of Acupuncture on Force and Delayed Onset of Muscle Soreness.

Background: The ability to produce force is critical to several daily activities. Strategies to reduce delayed onsent muscle soreness (DOMS) and restore force-generating properties that occur in response to training and impair physical performance have been proposed. Acupuncture has been proposed to accelerate recovery and optimize muscle functioning. It was to determine the effects of acupuncture on DOMS and on the muscle force production capacity. Methods: Thirty physically active volunteers (26.3 ± 3.1 years old, 1.70 ± 0.08 m, 66.5 ± 12.6 kg) were allocated in a control (CG; n = 10), placebo (PG; n = 10), and acupuncture (AG; n = 10) groups. The groups were subjected to an exercise protocol to induce DOMS and were assessed for muscle force, threshold, and rate of perceived pain and activation of the biceps brachialis muscle before (PRE) and 20 minutes after (POST) a single acupuncture session using a mixed model analysis. Results: The threshold and rate of perceived pain were reduced in the AG (P < 0.05) but remained unchanged in the other groups (P > 0.05). Muscle activation also showed larger changes in the AG in comparison with the other groups (P < 0.05). No changes in the ability to produce force were found after acupuncture in any groups (P > 0.05). Conclusions: Acupuncture may reduce discomfort and improve muscle activation but was not effective to promote force improvement and/or restore the force-generating properties. It may be speculated that muscle disruption may have played a role and did not allow participants to restore their muscular performance. Rebec Number; RBR-8bh5k7 (www.ensaiosclinicos.gov.br/rg/RBR-8bh5k7); Clinical Trial Registry (UTN No.: U1111-1234-9553).

Physical Performance, Anthropometrics and Functional Characteristics Influence the Intensity of Nonspecific Chronic Low Back Pain in Military Police Officers.

Background: Chronic low back pain (CLBP) is a serious problem in Military Police Officers (MPO), which accounts for up to 45% of the sick leave rates. It has been assumed that the strength and the endurance of trunk flexor and extensor muscles are CLPB key factors, but it is not known whether these attributes are related to pain intensity. It was aimed to determine whether the strength and endurance of trunk flexor and extensor muscles differ in MPO with no pain (CON; n = 24), moderate (MOD; n = 42), and severe (SEV; n = 37) nonspecific chronic low back pain (CLBP). Methods: The peak torque and endurance test of trunk flexor (PTF.BM-1) and extensor (PTE.BM-1) muscles were compared. A multiple regression analysis was used to identify pain intensity predictors in all groups (PAIN) and according to pain intensity (MOD and SEV). Results: The PTF.BM-1 was negatively related to pain and was a significant predictor, irrespective of pain intensity (PAIN). Conclusion: When pain intensity was considered the PTF.BM-1 and PTE.BM-1 explained the pain in the MOD, while the PTE.BM-1 and service time explained pain intensity in the SEV. Endurance of the flexor and extensor muscles was not related to pain intensity. These results indicated that training protocols must emphasize specific strengthening routines.

Fish-oil supplementation enhances the effects of strength training in elderly women.

BACKGROUND: Muscle force and functional capacity generally decrease with aging in the older population, although this effect can be reversed, attenuated, or both through strength training. Fish oil (FO), which is rich in n-3 (omega-3) PUFAs, has been shown to play a role in the plasma membrane and cell function of muscles, which may enhance the benefits of training. The effect of strength training and FO supplementation on the neuromuscular system of the elderly has not been investigated. OBJECTIVE: The objective was to investigate the chronic effect of FO supplementation and strength training on the neuromuscular system (muscle strength and functional capacity) of older women. DESIGN: Forty-five women (aged 64 ± 1.4 y) were randomly assigned to 3 groups. One group performed strength training only (ST group) for 90 d, whereas the others performed the same strength-training program and received FO supplementation (2 g/d) for 90 d (ST90 group) or for 150 d (ST150 group; supplemented 60 d before training). Muscle strength and functional capacity were assessed before and after the training period. RESULTS: No differences in the pretraining period were found between groups for any of the variables. The peak torque and rate of torque development for all muscles (knee flexor and extensor, plantar and dorsiflexor) increased from pre- to posttraining in all groups. However, the effect was greater in the ST90 and ST150 groups than in the ST group. The activation level and electromechanical delay of the muscles changed from pre- to posttraining only for the ST90 and ST150 groups. Chair-rising performance in the FO groups was higher than in the ST group. CONCLUSIONS: Strength training increased muscle strength in elderly women. The inclusion of FO supplementation caused greater improvements in muscle strength and functional capacity.