Mark R. McKean

The lumbar and sacrum movement pattern during the back squat exercise.

McKean, MR, Dunn, PK, and Burkett, BJ. The lumbar and sacrum movement pattern during the back squat exercise. J Strength Cond Res 24(10): 2731-2741, 2010-An essential exercise for strength training of the lower limbs is the squat exercise. During this exercise, changes in lumbar lordosis are commonly used to indicate when the descent of the squat should cease, yet the behavior of the lumbar-scarum segments remains unclear. The purpose of this study was to quantify the lumbar-sacrum movements during the back squat, because the movement of the sacrum is influenced by the width of stance, this variable was also investigated. Thirty trained subjects, 18 men with 1 repetition maximum (1RM) squat of 123% (13.9%) of bodyweight and 12 women with 1RM squat of 93% (15.6%), performed a set of narrow and wide stance squats, each carrying an additional 50% of body weight as load. The timing and movement of the lumbar angle (T12/L1), sacrum angle (L5/S1), and lumbar flexion angle (lumbar lordosis) were measured in 3 dimensions for the ascent and decent phases. Men and women achieved similar lumbar angles for both width of stance and phase. Sacrum angles, lumbar flexion angles, and timing differed significantly (p < 0.05) between gender and width of stance. The lumbar flexion range during the descent phase for women in narrow and wide stance was 12.9° and 12.6°, respectively; for men, this range was significantly (p < 0.05) larger at 26.3° and 25.4°, respectively. Men and women developed different movement patterns for the squatting movement, and therefore, this needs to be considered in strength development and screening procedures. The lumbar spine became kyphotic as soon as a load was placed on the shoulders, and any teaching cues to maintain a curved lumbar spine when squatting must be questioned.

Quantifying the movement and the influence of load in the back squat exercise.

McKean, MR, Dunn, PK, and Burkett, BJ. Quantifying the movement and the influence of load in the back squat exercise. J Strength Cond Res 24(6): 1671-1679, 2010-The squat is used extensively in strength and conditioning, physical therapy, rehabilitation, and fitness programs. However, the movement pattern of the hip and knee is still relatively unknown, in particular, the timing of when maximum angles is reached. The purpose of this study was to quantify the hip and knee movements of the squat and establish if load alters these movements. Twenty-eight subjects (16 men and 12 women) performed 2 sets of 8 squats. Load was applied in random order as no additional weight (body weight [BW]) or an additional load of 50% of the subjects weight (BW+50%). Joint angles and time for hip and knee, as well as forward knee, displacement in the descent and ascent phases were measured with significance at p < 0.05. Regardless of gender, phase, and load, all subjects achieved their maximum hip and knee angles within 2% of the deepest position. Load significantly increased the flexion angle at the hip and knee joints in men. The knees movement forward of the toes ranged from 63.8 to 64.7 mm in men and 93.2 to 96.6 mm in women. A significant difference in the timing of when the maximum forward knee movement occurred was observed because of gender. The overriding factor for the practical prescription of squat technique was regardless of load, gender, or phase; the maximum angles of the hip and knee are reached almost simultaneously at the bottom of the squat. Furthermore, for all subjects, the knee moved forward of the toes when squatting with men reaching their maximum forward knee position around 84% of the descent phase, whereas this occurred for women around 93%.

The relationship between joint range of motion, muscular strength, and race time for sub-elite flat water kayakers.

Upper body strength and flexibility are common training activities in elite flat water kayaking yet the relationship between joint range of motion, muscular strength, and race time is unclear. The aim of this research was to firstly quantify the flexibility and strength of sub-elite kayakers and then determine the relationship of this data to performance race times. Twenty-nine national standard kayak paddlers were assessed for shoulder and pelvic flexibility, upper body strength, and performance time. The shoulder internal and external rotation range of movement for kayak paddlers was reduced in comparison to other populations. For the female paddlers significant (p<0.01) and strong correlations (r>0.70) were found between shoulder flexion range of movement, shoulder strength, and strength endurance. Strength scores for kayak paddlers are reported for the first time showing the Pull:Push strength ratio for male kayak paddlers was 129%, and for females 147%. The strength ratio was significantly different (p<0.01) across gender and also different to published ratios from other sports. Several other measures were also significantly different across gender. All paddlers showed significant and strong correlations between the three 8RM shoulder strength exercises, highlighting the importance of maintaining balance of strength for the muscles acting on the shoulder. There was only one measure, the strength endurance Bench-Pull-Max-Power for females that significantly and strongly correlated to the on-water performances; identifying the poor relationship between current dry land training activities and race performance. No single strength or ROM measure correlated strongly with on-water performances for either sex, as a sport kayaking appears to reduce the ROM about the shoulder joint.

Low-load high-repetition resistance training improves strength and gait speed in middle-aged and older adults

OBJECTIVES To determine the effect of 26 weeks of low-load high-repetition resistance training (BodyPump™) on maximal strength, gait speed, balance and self-reported health status in healthy, active middle-aged and older adults. DESIGN Two-group randomised control trial. METHODS Sixty-eight apparently healthy, active adults aged over 55 years completed either 26 weeks of BodyPump™ training (PUMP) or served as control participants (CON). The BodyPump™ group (n = 32, age = 66 ± 4 years) trained twice per week for 26 weeks while the control group (n = 36, age = 66 ± 5 years) continued with their normal activities. Leg-press and Smith-machine bench-press one repetition maximum (1RM), gait speed, balance, and self-reported health status were all assessed at baseline and follow-up. RESULTS Significant group-by-time interactions in favour of the BodyPump™ group were found for leg-press 1RM (PUMP + 13%, CON + 3%, p = 0.007, partial eta(2) = 0.11), Smith-machine bench-press 1RM (PUMP + 14%, CON +5%, p = 0.001, partial eta(2) = 0.18), normal gait speed (PUMP + 23%, CON +9 %, p = 0.028, partial eta(2) = 0.08) and single leg balance right (PUMP + 24%, CON - 7%, p = 0.006, partial eta(2) = 0.12). There were no group-by-time interactions for health status measures. Three participants in the BodyPump™ group withdrew from training due to injury or fear of injury related to training. CONCLUSIONS Low-load high-repetition resistance training in the form of BodyPump™ is effective at improving maximal strength, gait speed and some aspects of standing balance in adults over 55 years. The training was well tolerated by the majority of participants.

Effect of Chronic Training on Heart Rate Variability, Salivary IgA and Salivary Alpha-Amylase in Elite Swimmers with a Disability

The purpose of this study was to a) determine the heart rate variability (HRV) and saliva markers of immunity (salivary immunoglobulin A; sIgA) and stress (salivary alpha-amylase; sAA) responses to chronic training in elite swimmers with a disability; and b) identify the relationships between HRV, sIgA, sAA and training volume. Eight members of a high performance Paralympic swimming program were monitored for their weekly resting HRV, sIgA and sAA levels in the 14 weeks leading up to a major international competition. The 14 week training program included aerobic, anaerobic, power and speed, and taper training phases, while also incorporating two swimming step tests and two swimming competitions. Specific time (root mean square of the successive differences; RMSSD) and frequency (high frequency normalized units [HFnu]) domain measures, along with non-linear indices (standard deviation of instantaneous RR variability; SD1 and short term fractal scaling exponent; α1) of HRV were used for all analyses with effects examined using magnitude-based inferences. Relationships between HRV and saliva markers were identified by Spearman rank rho (ρ) correlation coefficients. Compared with week 1, SD1 was very likely lower (96/4/0, ES = -2.21), while sAA was very likely elevated (100/0/0, ES = 2.32) at the beginning of week 7 for all athletes. The training program did not alter HRV or saliva whereas competition did. There were also no apparent differences observed for HRV, sIgA and sAA between each of the training phases during the 14 week swimming program. Correlations were observed between sAA and SD1 (ρ = -0.212, p<0.05), along with sAA and mean HR (ρ = 0.309, p<0.05). These results show that high level national competition influences depresses HRV (SD1) and increases saliva biomarkers of stress (sAA). It appears that a well-managed and periodised swimming program can maintain these indices within normal baseline levels. The study also highlighted the parasympathetic nervous system influence on sAA.

Do the Nutrition Qualifications and Professional Practices of Registered Exercise Professionals Align

Australia has approximately 26,000 registered exercise professionals (REP), in comparison with 3,379 accredited practicing dietitians (APD). The REP workforce has the potential to reach more than 10% of the Australian population but there is limited data on their educational background and professional behaviors with regards to nutritional counseling of clients. The purpose of this research was to determine if REPs are working within their scope of practice and if their qualifications align with their practice, specifically as it relates to nutrition advice. Using a cross sectional descriptive study design, a self-administered online survey of REPs was conducted over 5 months. REPs were recruited through electronic and social media using a snowballing technique. The study focused on education, nutrition advice, and sources of information. A total of 286 respondents completed the survey, including 13 with tertiary dietetic qualifications i.e., APDs. The nationally recognized industry Certificate III/IV in Fitness was the most common qualification. The majority of REPs responding (88%) were working outside of their professional scope of practice, offering individual nutrition advice to clients across fitness and medical issues. This was despite 40% of REPs undertaking no further training in nutrition since graduating, and primarily basing advice on use of readily accessible sources of nutrition information. It is recommended the nutrition advice provided to REPs during training be limited to general nonmedical nutrition information in accordance with nationally endorsed evidence based guidelines and that issues pertaining to scope of practice be addressed with onward referral to other health professionals be advocated.

The Influence of Upper-Body Strength on Flat-Water Sprint Kayak Performance in Elite Athletes

Dry-land strength training is a fundamental component for elite kayak performance. The aims of this research were 3-fold: 1st, to determine the relationship between performance time and strength scores for elite kayakers; 2nd, to identify how strength changes (gains or losses) over 3 training y relate with changes in performance time for elite kayakers; and 3rd, to compare the progression in performance times for elite athletes with the top 3 performers from the national championships. The performance data for 15 elite male and 10 elite female kayakers were collected over 2 y. This group was reduced to 9 men and 8 women in the 3rd and final year. There were direct and significant correlations between strength scores and performance times across the 3 y. Bench-press 1RM increased by 34.8% for men and 42.3% for women. Over the 3 seasons, mean 1000-m time decreased by approximately 4.8%, 500-m times decreased by 7.3% (women), and 200-m times decreased by 9.1%. The womens 500-m changed from 11.9% difference from medalists to within 1.1% during the 3 y. During the 3 y of this study a change in 1-repetitionmaximum (1RM) bench press of 13% for men and 6.5% in women coincided with a change in performance times of 1%. For 1RM pull-up a change of 10% in men and 2.3% in women coincided with a change in performance times of 1%.

Twelve weeks of BodyBalance ® training improved balance and functional task performance in middle-aged and older adults

Purpose The purpose of the study was to evaluate the effect of BodyBalance® training on balance, functional task performance, fear of falling, and health-related quality of life in adults aged over 55 years. Participants and methods A total of 28 healthy, active adults aged 66±5 years completed the randomized controlled trial. Balance, functional task performance, fear of falling, and self-reported quality of life were assessed at baseline and after 12 weeks. Participants either undertook two sessions of BodyBalance per week for 12 weeks (n=15) or continued with their normal activities (n=13). Results Significant group-by-time interactions were found for the timed up and go (P=0.038), 30-second chair stand (P=0.037), and mediolateral center-of-pressure range in narrow stance with eyes closed (P=0.017). There were no significant effects on fear of falling or self-reported quality of life. Conclusion Twelve weeks of BodyBalance training is effective at improving certain balance and functional based tasks in healthy older adults.

Match demands of professional rugby football codes: A review from 2008 to 2015

Rugby football codes have continually increased in popularity and are played professionally around the world at domestic, national and international level. Coaching professionals can use the findings of this review to guide training practices for the professional rugby football player, particularly those players who may be competing concurrently or transferring between codes. The development of repeated high-intensity exercise ability should be a key emphasis of training programmes especially for players who are aiming to compete at higher competition standards. Importantly, there are considerable differences in repeated high-intensity exercise demands of match-play for different positional groups. For greatest transference to match performance, training programs should replicate the frequency and duration of repeated high-intensity exercise bouts in addition to the relative contribution of high-intensity running, tackling and physical collisions. Training programmes should not neglect developing players’ prolonged high-intensity running ability as high-speed running efforts may occur separately from repeated high-intensity exercise bouts and likely place considerable demands on rugby football players, particularly in rugby sevens competition. Rugby football players have been shown to experience transient fatigue patterns during match-play where teams may be susceptible to conceding points or sustaining injury. Improved physical conditioning strategies may reduce development of match-fatigue; however, research is yet to investigate the influence of fitness levels and team strategies. A better understanding of these factors and how they interact with match-fatigue will assist with the improvement of training practices for professional rugby football players.

Quantifying kinematic differences between land and water during squats, split squats, and single-leg squats in a healthy population

Aquatic exercises can be used in clinical and sporting disciplines for both rehabilitation and sports training. However, there is limited knowledge on the influence of water immersion on the kinematics of exercises commonly used in rehabilitation and fitness programs. The aim of this study was to use inertial sensors to quantify differences in kinematics and movement variability of bodyweight squats, split squats, and single-leg squats performed on dry land and whilst immersed to the level of the greater trochanter. During two separate testing sessions, 25 active healthy university students (22.3±2.9 yr.) performed ten repetitions of each exercise, whilst tri-axial inertial sensors (100 Hz) recorded their trunk and lower body kinematics. Repeated-measures statistics tested for differences in segment orientation and speed, movement variability, and waveform patterns between environments, while coefficient of variance was used to assess differences in movement variability. Between-environment differences in segment orientation and speed were portrayed by plotting the mean difference ±95% confidence intervals (CI) throughout the tasks. The results showed that the depth of the squat and split squat were unaffected by the changed environment while water immersion allowed for a deeper single leg squat. The different environments had significant effects on the sagittal plane orientations and speeds for all segments. Water immersion increased the degree of movement variability of the segments in all exercises, except for the shank in the frontal plane, which showed more variability on land. Without compromising movement depth, the aquatic environment induces more upright trunk and shank postures during squats and split squats. The aquatic environment allows for increased squat depth during the single-leg squat, and increased shank motions in the frontal plane. Our observations therefore support the use of water-based squat tasks for rehabilitation as they appear to improve the technique without compromising movement depth.