Healy, R, Smyth, C, Kenny, IC, and Harrison, AJ. Influence of reactive and maximum strength indicators on sprint performance. J Strength Cond Res 33(11): 3039–3048, 2019—The primary aim of this study was to assess the relationship between reactive and maximal strength measures with 40 m sprint performance and mechanical properties. Fourteen male and 14 female sprinters participated in this study. On the first day, subjects performed 40 m sprints with 10-m split times recorded in addition to maximal theoretical velocity, maximal theoretical force and peak horizontal power, which were calculated from force–velocity relationships. On the second day, subjects performed isometric midthigh pulls (IMTPs) with peak force (PF) and relative PF calculated, drop jumps (DJs) and vertical hopping where the reactive strength index (RSI) was calculated as jump height (JH) divided by contact time (CT). Pearson correlations were used to assess the relationships between measures and independent samples t-tests were used to assess the differences between men and women. No significant correlations were found between DJ and hopping RSI and sprint measures. A significant strong positive correlation was found between IMTP PF and peak horizontal power in men only (r = 0.61). The male sprinters performed significantly better in all recorded measures apart from hopping (CT, JH and RSI) and DJ CT where no significant differences were found. The lack of association between reactive and maximal strength measures with sprint performance is potentially because of the test's prolonged CTs relative to sprinting and the inability to assess the technical application of force. Several methods of assessing reactive strength are needed that can better represent the demands of the distinct phases of sprinting e.g., acceleration, maximum velocity.

There is no gold standard diagnostic method for breathing pattern disorders (BPD) which is commonly diagnosed through the exclusion of other pathologies. Optoelectronic plethysmography (OEP) is a 3D motion capture technique that provides a comprehensive noninvasive assessment of chest wall during rest and exercise. The purpose of this study was to determine if OEP can distinguish between active individuals classified with and without BPD at rest and during exercise. Forty-seven individuals with a healthy breathing pattern (HBP) and twenty-six individuals with a BPD performed a submaximal exercise challenge. OEP measured the movement of the chest wall through the calculation of timing, percentage contribution, and phase angle breathing pattern variables. A mixed model repeated measures ANOVA analysed the OEP variables between the groups classified as HBP and BPD at rest, during exercise, and after recovery. At rest, regional contribution variables including ribcage percentage contribution (HBP: 71% and BPD: 69%), abdominal ribcage contribution (HBP: 13% and BPD: 11%), abdomen percentage contribution (HBP: 29% and BPD: 31%), and ribcage and abdomen volume index (HPB: 2.5 and BPD: 2.2) were significantly different between groups. During exercise, BPD displayed significantly more asynchrony between various thoracic compartments including the ribcage and abdomen phase angle (HBP: −1.9 and BPD: −2.7), pulmonary ribcage and abdomen phase angle (HBP: −0.5 and BPD, 0.5), abdominal ribcage and shoulders phase angle (HBP: −0.3 and BPD: 0.6), and pulmonary ribcage and shoulders phase angle (HBP: 0.2 and BPD: 0.6). Additionally, the novel variables inhale deviation (HBP: 8.8% and BPD: 19.7%) and exhale deviation (HBP: −10.9% and BPD: −17.6%) were also significantly different between the groups during high intensity exercise. Regional contribution and phase angles measured via OEP can distinguish BPD from HBP at rest and during exercise. Characteristics of BPD include asynchronous and thoracic dominant breathing patterns that could form part of future objective criteria for the diagnosis of BPD.

Dysfunctional breathing patterns (DBP) can have an impact on an individual’s quality of life and/or exercise performance. Breathing retraining is considered to be the first line of treatment to correct breathing pattern, for example, reducing ribcage versus abdominal movement asynchrony. Optoelectronic plethysmography (OEP) is a non-invasive 3D motion capture technique that measures the movement of the chest wall. The purpose of this study was to investigate if the use of a newly developed real-time OEP phase angle and volume feedback system, as an acute breathing retraining intervention, could result in a greater reduction of phase angle values (i.e., an improvement in movement synchrony) when compared to real-time OEP volume feedback alone. Eighteen individuals with a DBP performed an incremental cycle test with OEP measuring chest wall movement. Participants were randomly assigned to either the control group, which included the volume-based OEP feedback or to the experimental group, which included both the volume-based and phase angle OEP feedback. Participants then repeated the same cycle test using the real-time OEP feedback. The phase angle between the ribcage versus abdomen (RcAbPhase), between the pulmonary ribcage and the combined abdominal ribcage and abdomen (RCpAbPhase), and between the abdomen and the shoulders (AbSPhase) were calculated during both cycle tests. Significant increases in RcAbPhase (pre: −2.89°, post: −1.39°, p < 0.01), RCpAbPhase (pre: −2.00°, post: −0.50°, p < 0.01), and AbSPhase (pre: −2.60°, post: −0.72°, p < 0.01) were found post-intervention in the experimental group. This indicates that the experimental group demonstrated improved synchrony in their breathing pattern and therefore, reverting towards a healthy breathing pattern. This study shows for the first time that dysfunctional breathing patterns can be acutely improved with real-time OEP phase angle feedback and provides interesting insight into the feasibility of using this novel feedback system for breathing pattern retraining in individuals with DBP.

Dysfunctional breathing pattern (DBP) is a term that can be used to describe a collection of breathing disorders in which an individual displays chronic changes in breathing pattern. This can occur with or without another respiratory disorder/disease. Currently, there is no diagnostic method for DBP and it is diagnosed through the exclusion of other pathologies. Optoelectronic plethysmography (OEP) is a 3D motion capture technique which allows for a noninvasive method of measuring the movement of the chest wall, compartmentalizing the torso. The purpose of this study was to investigate if OEP could differ between athletes with and without a dysfunctional breathing pattern during exercise. Forty-seven athletes with a healthy breathing pattern (HBP) and twenty-six athletes with a suspected dysfunctional breathing pattern (DBP) performed an incremental cycle test to volitional exhaustion. Inspiratory time (tI), expiratory time (tE), the phase angle between the left and right side of the pulmonary ribcage (RCpHTA), between the pulmonary and abdominal ribcage (RCpRCaPhase), between the shoulders and the abdominal ribcage (RCaSPhase), and between the shoulders and the pulmonary ribcage (RCpSPhase) were calculated at rest and during high intensity exercise. It was found that each breathing parameters displayed no significant differences between the two groups at rest. However, during high intensity exercise these breathing patterns were found to be significantly different. The DBP group displayed significantly lower values for tI (HBP: 0.9 s, DBP: 0.8 s) and tE (HBP: 1.0 s, DBP: 0.8 s) and significantly higher values for each of the phase angles when compared to the healthy group, including RCpHTA (HBP: 0.0°, DBP: 0.2 °), RCpRCaPhase (HBP: −0.4 °, DBP: 0.5 °), RCaSPhase (HBP: −0.3 °, DBP: 0.5 °), and RCpSPhase (HBP: 0.2 °, DBP: 0.6 °). This indicates that individuals with a DBP took shorter breaths and had greater asynchrony within their breathing pattern during exercise but not at rest. This also demonstrates that OEP is sensitive enough to detect differences between these two group during high intensity exercise.

A non-invasive wearable device (Smartlifeinc Limited) has been developed integrating impedance pneumography (IP) into a compression garment using textile sensors to measure respiration. The purpose of this study was to validate the wearable device to measure breathing frequency (BF) during rest and exercise, and to compare the results obtained using a frequency (FD) versus a time domain (TD) algorithm to analyse the impedance signal. Five healthy male participants completed an incremental cycle test with data being collected using the wearable device and by a breath-by-breath analyser, which acted as the gold standard. BF was recorded for 30 seconds at rest, three different exercise intensities (low, moderate, and high) and during the recovery phase post exercise. Using a TD and FD algorithm, BF was calculated at each phase from the IP data and then compared to the BF obtained from the breath-by-breath analyser. The TD algorithm had a closer agreement with the breath-by-breath analyser at the three exercise intensities and recovery phase, (RMSD: 7.86, 4.81, 5.98, and 2.84 b.min-1) for low, moderate, high intensities and recovery phase respectively, when compared to the FD algorithm (RMSD: 9.68, 9.37, 10.32, and 6.14 b.min-1). However, the FD algorithm showed a closer agreement during the rest phase (RMSD: 4.33 b.min-1, TD algorithm: 8.20 b.min-1). This preliminary study demonstrates the promising potential use of IP in wearable technology to measure BF. Ongoing testing of additional participants will inform the choice of algorithm to be utilised and whether IP may be used to calculate additional measures such as lung volumes.