A novel approach to thermographic images analysis of equine thoracolumbar region: the effect of effort and rider's body weight on structural image complexity.

BACKGROUND: The horses' backs are particularly exposed to overload and injuries due to direct contact with the saddle and the influence of e.g. the rider's body weight. The maximal load for a horse's back during riding has been suggested not to exceed 20% of the horses' body weight. The common prevalence of back problems in riding horses prompted the popularization of thermography of the thoracolumbar region. However, the analysis methods of thermographic images used so far do not distinguish loaded horses with body weight varying between 10 and 20%. RESULTS: The superficial body temperature (SBT) of the thoracolumbar region of the horse's back was imaged using a non-contact thermographic camera before and after riding under riders with LBW (low body weight, 10%) and HBW (high body weight, 15%). Images were analyzed using six methods: five recent SBT analyses and the novel approach based on Gray Level Co-Occurrence Matrix (GLCM) and Gray Level Run Length Matrix (GLRLM). Temperatures of the horse's thoracolumbar region were higher (p < 0.0001) after then before the training, and did not differ depending on the rider's body weight (p > 0.05), regardless of used SBT analysis method. Effort-dependent differences (p < 0.05) were noted for six features of GLCM and GLRLM analysis. The values of selected GLCM and GLRLM features also differed (p < 0.05) between the LBW and HBW groups. CONCLUSION: The GLCM and GLRLM analyses allowed the differentiation of horses subjected to a load of 10 and 15% of their body weights while horseback riding in contrast to the previously used SBT analysis methods. Both types of analyzing methods allow to differentiation thermal images obtained before and after riding. The textural analysis, including selected features of GLCM or GLRLM, seems to be promising tools in considering the quantitative assessment of thermographic images of horses' thoracolumbar region.

Effects of Two Passive Back-Support Exoskeletons on Muscle Activity, Energy Expenditure, and Subjective Assessments During Repetitive Lifting.

OBJECTIVE: The aim of this study was to explore the efficacy of two different passive back-support exoskeleton (BSE) designs during repetitive lifting in different postures. BACKGROUND: Although BSEs have been proposed as a potential intervention for reducing physical demands, limited information is available about the impacts of different exoskeleton designs in diverse work scenarios. METHOD: Eighteen participants (gender-balanced) performed lab-based simulations of repetitive lifting tasks. These tasks were performed in 12 different conditions, involving two BSEs and a control condition, two levels of lifting symmetry (symmetric and asymmetric), and two postures (standing and kneeling). Outcome measures described muscle activity and energy expenditure, along with perceived discomfort, balance, and usability. RESULTS: Using both BSEs significantly reduced peak activity of the trunk extensor muscles (by ~10%-28%) and energy expenditure (by ~4%-13%) in all conditions tested. Such reductions, though, were task dependent and differed between the two BSEs. In most of the tested conditions, using BSEs positively affected subjective responses regarding perceived exertion and usability. CONCLUSION: Our results suggest that the beneficial effects of a BSE are task specific and depend on the specific BSE design approach. More work is needed, though, to better characterize this task specificity and to determine the generalizability of BSE effects on objective and subjective outcomes for a wider range of conditions and users. APPLICATION: Our results provide new evidence to guide the selection and application of passive BSE designs in diverse lifting tasks.

Commercially Available Friction-Reducing Patient-Transfer Devices Reduce Biomechanical Stresses on Caregivers' Upper Extremities and Low Back.

OBJECTIVE: The aim of this study was to evaluate the efficacy of commercially available friction-reducing patient-transfer devices in reducing biomechanical stresses on caregivers and patients. BACKGROUND: Caregivers suffer from high prevalence of work-related musculoskeletal disorders, which is associated with manual patient handling. However, there is not enough information available on the efficacy of various friction-reducing devices in reducing biomechanical stresses in the upper extremities and low back. METHOD: During patient-transfer tasks performed by 20 caregivers, we measured hand force; shoulder and trunk posture; shoulder moment; muscle activity in the flexor digitorum superficialis, extensor digitorum communis, biceps, triceps, trapezius, and erector spinae; and usability ratings from four devices: a draw sheet, a repositioning sheet, a slide board, and an air-assisted device. In addition, triaxial head acceleration of mock patients was measured to evaluate patients' head acceleration. RESULTS: The slide board and air-assisted device significantly reduced hand force (p < .001), shoulder flexion (p < .001), shoulder moment (p < .001), muscle activities of caregivers (p < .004), and patients' head acceleration (p < .023) compared with the draw sheet. However, no significant differences in biomechanical measures were found between the repositioning and draw sheets. The air-assisted device consistently showed the lowest biomechanical stresses and was most preferred by participants. CONCLUSION: Reduction in caregivers' biomechanical stresses and mock patients' head acceleration indicates that a slide board and an air-assisted device can be effective engineering controls to reduce risk of injury. APPLICATION: The study results can provide a recommendation for engineering controls to reduce biomechanical stresses for both caregivers and patients.

Specificity and Transfer of Lower-Body Strength: Influence of Bilateral or Unilateral Lower-Body Resistance Training.

Appleby, BB, Cormack, SJ, and Newton, RU. Specificity and transfer of lower-body strength: Influence of bilateral or unilateral lower-body resistance training. J Strength Cond Res 33(2): 318-326, 2019-To examine the development of lower-body strength using either bilateral or unilateral resistance training. Developmental rugby players (n = 33; mean training age = 5.4 ± 2.9 years; 1 repetition maximum [1RM] 90° squat = 178 ± 27 kg) completed an 18-week randomized controlled training design (bilateral group [BIL], n = 13; unilateral group [UNI], n = 10; comparison, n = 10). The 8-week training phase involved 2 lower-body, volume-load matched resistance sessions per week (6-8 sets × 4-8 reps at 45-88% 1RM), differing only in the prescription of a bilateral (back squat) or unilateral (step-up) resistance exercise. Maximum strength was assessed by a randomized order of 1RM back squat and step-up testing and analyzed for within- and between-group differences using effect sizes (ES ± 90% confidence limits [CL]). Both training groups showed practically important improvements in their trained exercise (ES ± 90% CL: BIL = 0.67 ± 0.48; UNI = 0.74 ± 0.38) with transfer to their nontrained resistance exercise (BIL step-up = 0.27 ± 0.39: UNI squat = 0.42 ± 0.39). The difference between groups in adaptation of squat strength was unclear (BIL ES = -0.34 ± 0.55), while the UNI group showed an advantage in step-up training (ES = 0.41 ± 0.36). The results demonstrate that practically important increases in lower-body strength can be achieved using bilateral or unilateral resistance training and development of that strength may be expressed in the movement not trained, supporting the transfer of strength training between exercises of similar joint movements and muscles. Coaches may choose to incorporate unilateral strength training where the prescription of bilateral training may be inhibited.

Effects of backpack and double pack loads on postural stability.

Measurement of postural stability is crucial for identifying predictors of performance, determining the efficacy of physical training and rehabilitation techniques and evaluating and preventing injuries, particularly for heavy load carriage in hikers, mountain search and rescue personnel and soldiers. This study investigated the effect of load distribution on postural stability in an upright stance using backpack and double pack loads under conflicting or impaired somatosensory, visual and vestibular conditions. The sensory organisation tests were conducted on 20 young adults before and after a 10-min level walking exercise. Young adults' ability to use inputs from somatosensory and visual systems to maintain postural stability was significantly reduced following a 10-min walking exercise with a heavy backpack (30% of body weight), whereas no significant changes were observed for double pack carriage. Thus, the distribution of heavy loads to the front and back provides superior balance control compared with back-only loading. Practitioner summary: This study investigated the effects of heavy (30% of body weight) load distribution on postural stability after a 10-min walking exercise. Backpack carriage significantly reduced postural stability, whereas there was no significant effect under double pack loads. Distribution of heavy loads on the front-and-back is desirable for superior balance control.

Effects of backpack weight on the performance of basic short-term/working memory tasks during flat-surface standing.

This study empirically investigated the effects of backpack weight on the performance of three basic short-term/working memory (STM/WM) tasks during flat-surface standing. Four levels of backpack weight were considered: 0, 15, 25 and 40% of the body weight. The three STM/WM tasks were the Corsi block, digit span and 3-back tasks, corresponding to the visuo-spatial sketchpad, phonological loop and central executive of WM, respectively. Thirty participants conducted the STM/WM tasks while standing with loaded backpack. Major study findings were that (1) increased backpack weight adversely affected the scores of all three STM/WM tasks; and, (2) the adverse effect of backpack weight was less pronounced for the phonological loop STM task than the other STM/WM tasks. The study findings may help understand and predict the impacts of body-worn equipment weight on the worker's mental task performance for various work activities requiring simultaneous performance of mental and physical tasks. Practitioner summary: The current study empirically examined the effects of backpack weight on the performance of three basic STM/WM tasks. The study findings entail that reduces the weight of body-worn equipment can positively impact the worker's mental task performance in addition to reducing the worker's bodily stresses. Abbreviations: ACC: anterior cingulate cortex; AP: anterior-posterior; BW: body weight; CoP: centre of pressure; C-S: central executive working memory task and standing; DLPFC: dorsolateral prefrontal cortex; HIP: human information processing; ML: medio-lateral; PMC: premotor cortex; P-S: phonological loop short-term memory task and standing; SMA: supplementary motor area; STM: short-term memory; VLPFC: ventrolateral prefrontal cortex; V-S: visuo-spatial short-term memory task and standing; WM: working memory.

Gait Symmetry Assessment with a Low Back 3D Accelerometer in Post-Stroke Patients.

Gait asymmetry is an important marker of mobility impairment post stroke. This study proposes a new gait symmetry index (GSI) to quantify gait symmetry with one 3D accelerometer at L3 (GSIL3). GSIL3 was evaluated with 16 post stroke patients and nine healthy controls in the Six-Minute-Walk-Test (6-MWT). Discriminative power was evaluated with Wilcoxon test and the effect size (ES) was computed with Cliff's Delta. GSIL3 estimated during the entire 6-MWT and during a short segment straight walk (GSIL3straight) have comparable effect size to one another (ES = 0.89, p < 0.001) and to the symmetry indices derived from feet sensors (|ES| = [0.22, 0.89]). Furthermore, while none of the indices derived from feet sensors showed significant differences between post stroke patients walking with a cane compared to those able to walk without, GSIL3 was able to discriminate between these two groups with a significantly lower value in the group using a cane (ES = 0.70, p = 0.02). In addition, GSIL3 was strongly associated with several symmetry indices measured by feet sensors during the straight walking cycles (Spearman correlation: |ρ| = [0.82, 0.88], p < 0.05). The proposed index can be a reliable and cost-efficient post stroke gait symmetry assessment with implications for research and clinical practice.

Backpack Forces on the Spine.

OBJECT: Backpacks are standard load carriers for people of all ages, especially school children and the military. Previous studies have described the impact of the forces exerted by backpacks on load distribution, back pain, and gait. The objective of this study was to use finite element analysis (FEA) to assess the effects of incremental weights in a backpack on the spine. METHODS: To assess the forces experienced by the spine under the incremental addition of weight to a backpack, we performed a finite element simulation using commercially available 'BodyParts3D/Anatomography' data, which were imported into FEA software. We studied two different scenarios: 1) a regular backpack with incrementally placed weights using both shoulder straps with the spine in a neutral position, and 2) a regular backpack with incrementally placed weights using both shoulder straps with the spine tilted forward 20 degrees. The spine model was physiologically accurate. RESULTS: For all of the added weights examined (1-100 pounds; 0.45-45.36 kg), the force experienced by the neutral spine was 7.2-fold the added weight. For the 20 degrees-forward posture, this value rose to 11.6-fold. CONCLUSIONS: These findings should help to clarify the forces experienced by the spine due to objects in a backpack. For example, this should help spinal surgeons to better understand the tremendous importance of sagittal plane alignment in planning their surgical reconstructions.

Kinetic Analysis of Isometric Back Squats and Isometric Belt Squats.

Layer, JS, Grenz, C, Hinshaw, TJ, Smith, DT, Barrett, SF, and Dai, B. Kinetic analysis of isometric back squats and isometric belt squats. J Strength Cond Res 32(12): 3301-3309, 2018-Belt squats seem to provide an alternative to back squats. However, it is not clear how musculoskeletal loading differs between the two. This study compared lower extremity and low-back kinetics during isometric back squats and isometric belt squats. Sixteen men (age: 22.6 ± 3.4 years; height: 1.74 ± 0.11 m; mass: 82.0 ± 5.6 kg) and 10 women (age: 21.5 ± 2.5 years; height: 1.64 ± 0.10 m; mass: 68.9 ± 7.1 kg) performed isometric back squats and belt squats at 4 squat depths. Joint resultant moments were calculated from kinematic and ground reaction force data. Linear interpolation was used to estimate peak vertical forces and joint moments at a 45° thigh segment angle. Subjects increased peak forces, ankle moments, and knee moments but decreased low-back moments from back to belt squats (p ≤ 0.023). Hip moments did not significantly change between 2 squats. Subjects demonstrating smaller ankle and knee moments during back squats showed greater increases in these moments from back to belt squats (p ≤ 0.012, R ≤ 0.24). Subjects whose back squats were characterized by greater low-back moments displayed greater decreases in low-back moments from back to belt squats (p < 0.001, R = 0.98). Compared with isometric back squats, isometric belt squats may provide a similar or greater external loading for the musculoskeletal system of the lower extremities while reducing external spinal loading. Belt squats may be considered by individuals with upper-body or spinal injuries and those displaying excessive external back moments.

Acute Effects of the Elevation Training Mask on Strength Performance in Recreational Weight lifters.

Jagim, AR, Dominy, TA, Camic, CL, Wright, G, Doberstein, S, Jones, MT, and Oliver, JM. Acute effects of the elevation training mask on strength performance in recreational weightlifters. J Strength Cond Res 32(2): 482-489, 2018-The Elevation Training Mask 2.0 (ETM) is a novel device that purportedly simulates altitude training. The purpose of this study was to investigate the acute effects of the ETM on resistance exercise performance, metabolic stress markers, and ratings of mental fatigue. Twenty male recreational weight lifters completed 2 training sessions of back squat and bench press (6 sets of 10 repetitions at 85% of 5-repetition maximum and seventh set to failure) as well as a maximal effort sprint test (18% body mass) with the mask (ETM) and without the mask (NM). Training evaluation included baseline and postexercise blood lactate and oxygen saturation measures. Performance evaluation included peak and average velocity bar velocity, total volume load, total work, total repetitions completed, and sprint performance. Adverse side effects were reported in 12% (n = 3) of participants, which included feelings of light headedness, anxiety, and discomfort. No differences were found in repetitions or total workload in back squat (p = 0.07) or bench press (p = 0.08) between conditions. A lower peak velocity was identified during the back squat, bench press, and sprint test in the ETM condition (p = 0.04). Blood lactate values were lower after bench press and sprint during the ETM condition (p < 0.001). Significantly lower ratings of alertness and focus for task were found after squat, bench press, and sprint test in the ETM condition compared with the NM condition (p < 0.001). Wearing the ETM during bouts of resistance training did not hinder the ability to achieve desired training volumes during the resistance training session. However, wearing the ETM does seem to attenuate the ability to maintain working velocity during training bouts and negatively influence ratings of alertness and focus for task.

Effects of backpack load and positioning on nonlinear gait features in young adults.

Overloaded backpacks can cause changes in posture and gait dynamic balance. Therefore, the aim of this study was to assess gait regularity and local dynamic stability in young adults as they carried a backpack in different positions, and with different loads. Twenty-one healthy young adults participated in the study, carrying a backpack that was loaded with 10 and 20% of their body weight (BW). The participants walked on a level treadmill at their preferred walking speeds for 4 min under different conditions of backpack load and position (i.e. with backpack positioned back bilaterally, back unilaterally, frontally or without a backpack). Results indicate that backpack load and positioning significantly influence gait stability and regularity, with the exception of the 10% BW bilateral back position. Therefore, the recommended safe load for school-age children and adolescents (10% of BW) should also be considered for young adults. Practitioner summary: Increase in load results in changes in posture, muscle activity and gait parameters, so we investigated the gait adaptations related to regularity and stability. Conditions with high backpack loads significantly influenced gait stability and regularity in a position-dependent manner, except for 10% body weight bilateral back position.

A comparison of economy and sagittal plane trunk movements among back-, back/front- and head-loading.

It has been suggested that freedom of movement in the trunk could influence load carriage economy. This study aimed to compare the economy and sagittal plane trunk movements associated with three load carriage methods that constrain posture differently. Eighteen females walked at 3 km.h-1 with loads of 0, 3, 6, 9, 12, 15 and 20 kg carried on the back, back/front and head. Load carriage economy was assessed using the Extra Load Index (ELI). Change in sagittal plane trunk forward lean and trunk angle excursion from unloaded to loaded walking were assessed. Results show no difference in economy between methods (p = .483), despite differences in the change in trunk forward lean (p = .001) and trunk angle excursion (p = .021) from unloaded to loaded walking. We conclude that economy is not different among the three methods of load carriage, despite significant differences in sagittal plane trunk movements. Practitioner summary: This article shows, based on mean data, that there is no difference in economy among back, back/front and head-loading, despite differences in trunk movement. It is possible a combination of factors align to influence individual economy, rather than a single set of factors, applicable to all individuals for each method.

Accuracy of identification of low or high risk lifting during standardised lifting situations.

The aim was to classify lifting activities into low and high risk categories (according to The Danish Working Environment Authority guidelines) based on surface electromyography (sEMG) and trunk inclination (tri-axial accelerometer) measurements. Lifting tasks with different weights, horizontal distance and technique were performed. The lifting tasks were characterised by a feature vector composed of either the 90th, 95th or 99th percentile of sEMG activity level and trunk inclinations during the task. Linear Discriminant Analysis and a subject-specific threshold scheme were applied and lifting tasks were classified with an accuracy of 65.1-65.5%. When lifts were classified based on the subject-specific threshold scheme from low and upper back accelerometers, the accuracy reached 52.1-58.1% and 72.7-78.1%, respectively. In conclusion, the use of subject-specific thresholds from sEMG from upper trapezius and erector spinae as well as inclination of the upper trunk enabled us to identify low and high risk lifts with an acceptable accuracy. Practitioner Summary: This study contributes to the development of a method enabling the automatic detection of high risk lifting tasks, i.e. exposure to high biomechanical loads, based on individual sEMG and kinematics from an entire working day. These methods may be more cost-effective and may complement observations commonly used by practitioners.

The Effects of a Heel Wedge on Hip, Pelvis and Trunk Biomechanics During Squatting in Resistance Trained Individuals.

Barbell back squats are a popular exercise for developing lower extremity strength and power. However, this exercise has potential injury risks, particularly to the lumbar spine, pelvis, and hip joint. Previous literature suggests heel wedges as a means of favorably adjusting trunk and pelvis kinematics with the intention of reducing such injury risks. Yet no direct biomechanical research exists to support these recommendations. Therefore, the purpose of this study was to examine the effects of heel wedges compared with barefoot on minimally loaded barbell back squats. Fourteen trained male participants performed a barbell back squat in bare feet or with their feet raised bilaterally with a 2.5-cm wooden block while 3-dimensional kinematics, kinetics, and electromyograms were collected. The heel wedge condition elicited significantly less forward trunk flexion angles at peak knee flexion, and peak external hip joint moments (p ≤ 0.05) compared with barefoot conditions. However, no significant differences were observed between conditions for trunk and pelvis angle differences at peak knee flexion (p > 0.05). Lastly, no peak or root mean square differences in muscle activity were elicited between conditions (p > 0.05). Our results lend support for the suggestions provided in literature aimed at using heel wedges as a means of reducing excessive forward trunk flexion. However, the maintenance of a neutral spine, another important safety factor, is not affected by the use of heel wedges. Therefore, heel wedges may be a viable modification for reduction of excessive forward trunk flexion but not for reduction in relative trunk-pelvis flexion during barbell back squats.

Muscle Activation Differs Between Partial and Full Back Squat Exercise With External Load Equated.

Changes in range of motion affect the magnitude of the load during the squat exercise and, consequently, may influence muscle activation. The purpose of this study was to evaluate muscle activation between the partial and full back squat exercise with external load equated on a relative basis between conditions. Fifteen young, healthy, resistance-trained men (age: 26 ± 5 years, height: 173 ± 6 cm) performed a back squat at their 10 repetition maximum (10RM) using 2 different ranges of motion (partial and full) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis, vastus medialis, rectus femoris, biceps femoris (BF), semitendinosus, erector spinae, soleus (SL), and gluteus maximus (GM). In general, muscle activity was highest during the partial back squat for GM (p = 0.004), BF (p = 0.009), and SL (p = 0.031) when compared with full-back squat. There was no significant difference for rating of perceived exertion between partial and full back squat exercise at 10RM (8 ± 1 and 9 ± 1, respectively). In conclusion, the range of motion in the back squat alters muscle activation of the prime mover (GM) and stabilizers (SL and BF) when performed with the load equated on a relative basis. Thus, the partial back squat maximizes the level of muscle activation of the GM and associated stabilizer muscles.

A Review of the Biomechanical Differences Between the High-Bar and Low-Bar Back-Squat.

Glassbrook, DJ, Helms, ER, Brown, SR, and Storey, AG. A review of the biomechanical differences between the high-bar and low-bar back-squat. J Strength Cond Res 31(9): 2618-2634, 2017-The back-squat is a common exercise in strength and conditioning for a variety of sports. It is widely regarded as a fundamental movement to increase and measure lower-body and trunk function, as well as an effective injury rehabilitation exercise. There are typically 2 different bar positions used when performing the back-squat: the traditional "high-bar" back-squat (HBBS) and the "low-bar" back-squat (LBBS). Different movement strategies are used to ensure that the center of mass remains in the base of support for balance during the execution of these lifts. These movement strategies manifest as differences in (a) joint angles, (b) vertical ground reaction forces, and (c) the activity of key muscles. This review showed that the HBBS is characterized by greater knee flexion, lesser hip flexion, a more upright torso, and a deeper squat. The LBBS is characterized by greater hip flexion and, therefore, a greater forward lean. However, there are limited differences in vertical ground reaction forces between the HBBS and LBBS. The LBBS can also be characterized by a greater muscle activity of the erector spinae, adductors, and gluteal muscles, whereas the HBBS can be characterized by greater quadriceps muscle activity. Practitioners seeking to develop the posterior-chain hip musculature (i.e., gluteal, hamstring, and erector muscle groups) may seek to use the LBBS. In comparison, those seeking to replicate movements with a more upright torso and contribution from the quadriceps may rather seek to use the HBBS in training.

Back extension exercises decompress the spinal root and improve standing mobility in patients with sub-acute lumbosacral radiculopathy.

PURPOSE: Repeated back extension exercises (RBEEs) have been reported to cause changes in the distribution and intensity of radicular symptoms. Therefore, the objective of this study was to investigate the effects of RBEEs on the neurophysiology of the compromised nerve root and on standing mobility and pain intensity in patients with sub-acute and chronic lumbosacral radiculopathy (LSR). SUBJECTS AND METHODS: A total of 40 patients with unilateral sub-acute/chronic LSR voluntarily participated in the study; the patients performed three sets of 10 RBEEs in the prone position with 1 min of rest between the sets. The soleus H-reflex, standing mobility, and pain intensity were recorded before and after the RBEEs. RESULTS: The results of the study showed that the RBEEs significantly improved the H-reflex, standing mobility, and pain intensity in patients with sub-acute LSR (p < .01); there was not a significant improvement in the patients with chronic LSR (p < .61). CONCLUSION: RBEEs in the prone position are recommended for improving the neurophysiological function of the compromised nerve root and standing mobility in patients with sub-acute LSR.

Hominis Placenta facilitates hair re-growth by upregulating cellular proliferation and expression of fibroblast growth factor-7.

BACKGROUND: Hominis Placenta (HP) known as a restorative medicine in Traditional Chinese Medicine (TCM), has been widely applied in the clinics of Korea and China as an anti-aging agent to enhance the regeneration of tissue. This study was conducted to investigate whether topical treatment of HP promotes hair regrowth in the animal model. METHODS: The dorsal hairs of 8-week-old C57BL/6 mice were depilated to synchronize hair follicles to the anagen phase. HP was applied topically once a day for 15 days. Hair growth was evaluated visually and microscopically. The incorporation of bromodeoxyuridine (BrdU) and expression of proliferating cell nuclear antigen (PCNA), fibroblast growth factor-7 (FGF-7) in dorsal skin tissue was examined by immunohistochemical analysis. Reverse transcription polymerase chain reaction (RT-PCR) was used to measure the mRNA expression of FGF-7. RESULTS: HP exhibited potent hair growth-promoting activity in C57BL/6 mice. Gross examination indicated that HP markedly increased hair regrowth as well as hair density and diameter. Histologic analysis showed that HP treatment enhanced the anagen induction of hair follicles. Immunohistochemical analysis revealed that BrdU incorporation and the expressions of PCNA were increased by treatment of HP. HP treatment significantly increased the expression of FGF-7, which plays pivotal roles to maintain anagen phase both protein and mRNA levels. CONCLUSIONS: Taken together, our results indicate that HP has a potent hair growth-promoting activity; therefore, it may be a good candidate for the treatment of alopecia.

Effects of Strength Training on Squat and Sprint Performance in Soccer Players.

Researchers have demonstrated that increases in strength result in increases in athletic performance, although the development of strength is still neglected in some sports. Our aim was to determine whether a simple in-season strength training program would result in increases in maximal squat strength and short sprint performance, in professional soccer players. Professional soccer players (n = 17, age = 18.3 ± 1.2 years, height = 1.79 ± 0.06 m, body mass [BM] = 75.5 ± 6.1 kg) completed 1 repetition maximum (1RM) back squat and sprint tests (5, 10, and 20 m) before and after a 6-week (×2 week) in-season strength training (85-90% 1RM) intervention. Strength training resulted in significant improvements in absolute and relative strength (before = 125.4 ± 13.8 kg, after = 149.3 ± 16.2 kg, p ≤ 0.001, Cohen's d = 0.62; 1RM/BM before: 1.66 ± 0.24 kg·kg, after = 1.96 ± 0.29 kg·kg, p ≤ 0.001, Cohen's d = 0.45; respectively). Similarly, there were small yet significant improvements in sprint performance over 5 m (before = 1.11 ± 0.04 seconds, after = 1.05 ± 0.05 seconds, p ≤ 0.001, Cohen's d = 0.55), 10 m (before = 1.83 ± 0.05 seconds, after = 1.78 ± 0.05 seconds, p ≤ 0.001, Cohen's d = 0.45), and 20 m (before = 3.09 ± 0.07 seconds, after = 3.05 ± 0.05 seconds, p ≤ 0.001, Cohen's d = 0.31). Changes in maximal squat strength seem to be reflected in improvements in short sprint performance highlighting the importance of developing maximal strength to improve short sprint performance. Moreover, this demonstrates that these improvements can be achieved during the competitive season in professional soccer players.

Working position influences the biomechanical demands on the lower back during dental hygiene.

This investigation monitored the biomechanical demands on the lower back during simulated dental hygiene work. A total of 19 female, registered dental hygienists performed 30 continuous minutes of manual scaling (plaque removal) of a manikin's teeth while seated. We monitored the working location and orientation of the dental hygienists, with respect to the manikin, along with their spine kinematics, spine extensor muscle activities and seat pressure, throughout the 30 min. A clock representation was used to express the working location. The location significantly influenced the dental hygienists' pelvic orientation with respect to the manikin, spine posture, erector muscle activity and pressure distribution. Findings from this study suggest that the prevalence of lower back pain amongst dental hygienists may be directly related to low-level tonic activity of the spine's extensor musculature, and the combined flexed and axially rotated spine postures. Practitioner Summary: Low back pain (LBP) is prevalent in dental hygienists, yet occupational demand on the low back has not been investigated. Posture, muscle activity and seat pressure were monitored. Combined spine rotation and flexion, and tonic activity of the extensor musculature may be related to LBP in dental hygienists.