Thoracic-Worn Accelerometers Detect Fatigue-Related Changes in Vertical Stiffness During Sprinting.

ABSTRACT: Horsley, BJ, Tofari, PJ, Halson, SL, Kemp, JG, Johnston, RD, and Cormack, SJ. Thoracic-worn accelerometers detect fatigue-related changes in vertical stiffness during sprinting. J Strength Cond Res 38(2): 283-289, 2024-Thoracic-mounted accelerometers are valid and reliable for analyzing gait characteristics and may provide the opportunity to assess running-related neuromuscular fatigue (NMF) during training and competition without the need for additional tests, such as a countermovement jump (CMJ). However, their sensitivity for detecting fatigue-related changes in gait across different speeds is unclear. We, therefore, assessed the changes in accelerometer-derived gait characteristics, including vertical stiffness (K vert ), following a repeated sprint protocol (RSP). Sixteen recreationally active subjects performed single and repeated CMJs on a force plate and 40 m run throughs overground at 3-4, 5-6, and 7-8 m·s -1 pre-post a 12 × 40 m RSP. Gait characteristics (contact time, step frequency, step length, K vert , etc.) were derived from an accelerometer contained within a global navigation satellite system unit on the thoracic spine using a validated algorithm. Changes in running gait and CMJ performance were assessed using a linear mixed-effects model (95% confidence interval [95% CI]; effect size [ES]). Significance was set at p < 0.05. A significant reduction in K vert occurred at 7-8 m·s -1 following the RSP (-8.51 kN·m -1 [-13.9, -3.11]; p = 0.007; ES [95% CI] = -0.39 [-0.62, -0.15]) which coincided with a decreased jump height (-0.03 m [-0.04, -0.01]; p = 0.002; ES [95% CI] = -0.87 [-1.41, -0.30]). However, all other gait characteristics were not significantly different irrespective of speed. Thoracic-worn accelerometers can detect changes in K vert at 7-8 m·s -1 which may be useful for monitoring NMF during sprinting. However, a RSP does not result in altered gait mechanics in subsequent running at lower speeds.

Validity and Reliability of Thoracic-Mounted Inertial Measurement Units to Derive Gait Characteristics During Running.

ABSTRACT: Horsley, BJ, Tofari, PJ, Halson, SL, Kemp, JG, Chalkley, D, Cole, MH, Johnston, RD, and Cormack, SJ. Validity and reliability of thoracic-mounted inertial measurement units to derive gait characteristics during running. J Strength Cond Res 38(2): 274-282, 2024-Inertial measurement units (IMUs) attached to the tibia or lumbar spine can be used to analyze running gait but, with team-sports, are often contained in global navigation satellite system (GNSS) units worn on the thoracic spine. We assessed the validity and reliability of thoracic-mounted IMUs to derive gait characteristics, including peak vertical ground reaction force (vGRF peak ) and vertical stiffness (K vert ). Sixteen recreationally active subjects performed 40 m run throughs at 3-4, 5-6, and 7-8 m·s -1 . Inertial measurement units were attached to the tibia, lumbar, and thoracic spine, whereas 2 GNSS units were also worn on the thoracic spine. Initial contact (IC) from a validated algorithm was evaluated with F1 score and agreement (mean difference ± SD ) of gait data with the tibia and lumbar spine using nonparametric limits of agreement (LoA). Test-retest error {coefficient of variation, CV (95% confidence interval [CI])} established reliability. Thoracic IMUs detected a nearly perfect proportion (F1 ≥ 0.95) of IC events compared with tibia and lumbar sites. Step length had the strongest agreement (0 ± 0.04 m) at 3-4 m·s -1 , whereas contact time improved from 3 to 4 (-0.028 ± 0.018 second) to 7-8 m·s -1 (-0.004 ± 0.013 second). All values for K vert fell within the LoA at 7-8 m·s -1 . Test-retest error was ≤12.8% for all gait characteristics obtained from GNSS units, where K vert was most reliable at 3-4 m·s -1 (6.8% [5.2, 9.6]) and vGRF peak at 7-8 m·s -1 (3.7% [2.5, 5.2]). The thoracic-spine site is suitable to derive gait characteristics, including K vert , from IMUs within GNSS units, eliminating the need for additional sensors to analyze running gait.

Does Site Matter? Impact of Inertial Measurement Unit Placement on the Validity and Reliability of Stride Variables During Running: A Systematic Review and Meta-analysis.

BACKGROUND: Inertial measurement units (IMUs) are used for running gait analysis in a variety of sports. These sensors have been attached at various locations to capture stride data. However, it is unclear if different placement sites affect the derived outcome measures. OBJECTIVE: The aim of this systematic review and meta-analysis was to investigate the impact of placement on the validity and reliability of IMU-derived measures of running gait. METHODS: Online databases SPORTDiscus with Full Text, CINAHL Complete, MEDLINE (EBSCOhost), EMBASE (Ovid) and Scopus were searched from the earliest record to 6 August 2020. Articles were included if they (1) used an IMU during running (2) reported spatiotemporal variables, peak ground reaction force (GRF) or vertical stiffness and (3) assessed validity or reliability. Meta-analyses were performed for a pooled validity estimate when (1) studies reported means and standard deviation for variables derived from the IMU and criterion (2) used the same IMU placement and (3) determined validity at a comparable running velocity (≤ 1 m·s-1 difference). RESULTS: Thirty-nine articles were included, where placement varied between the foot, tibia, hip, sacrum, lumbar spine (LS), torso and thoracic spine (TS). Initial contact, toe-off, contact time (CT), flight time (FT), step time, stride time, swing time, step frequency (SF), step length (SL), stride length, peak vertical and resultant GRF and vertical stiffness were analysed. Four variables (CT, FT, SF and SL) were meta-analysed, where CT was compared between the foot, tibia and LS placements and SF was compared between foot and LS. Foot placement data were meta-analysed for FT and SL. All data are the mean difference (MD [95%CI]). No significant difference was observed for any site compared to the criterion for CT (foot: - 11.47 ms [- 45.68, 22.74], p = 0.43; tibia: 22.34 ms [- 18.59, 63.27], p = 0.18; LS: - 48.74 ms [- 120.33, 22.85], p = 0.12), FT (foot: 11.93 ms [- 8.88, 32.74], p = 0.13), SF (foot: 0.45 step·min-1 [- 1.75, 2.66], p = 0.47; LS: - 3.45 step·min-1 [- 16.28, 9.39], p = 0.37) and SL (foot: 0.21 cm [- 1.76, 2.18], p = 0.69). Reliable derivations of CT (coefficient of variation [CV] < 9.9%), FT (CV < 11.6%) and SF (CV < 4.4%) were shown using foot- and LS-worn IMUs, while the CV was < 7.8% for foot-determined stride time, SL and stride length. Vertical GRF was reliable from the LS (CV = 4.2%) and TS (CV = 3.3%) using a spring-mass model, while vertical stiffness was moderately (r = 0.66) and nearly perfectly (r = 0.98) correlated with criterion measures from the TS. CONCLUSION: Placement of IMUs on the foot, tibia and LS is suitable to derive valid and reliable stride data, suggesting measurement site may not be a critical factor. However, evidence regarding the ability to accurately detect stride events from the TS is unclear and this warrants further investigation.

Long-term outcomes of primary single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S).

BACKGROUND: The long-term outcomes of primary single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) have never been reported in the literature. OBJECTIVES: The study aimed to evaluate the long-term outcomes after primary laparoscopic SADI-S (LSADI-S). SETTING: Single, private institute, United States. METHODS: Data from 750 patients who underwent a primary LSADI-S from June 2013 through November 2019 by 3 surgeons were retrospectively analyzed. RESULTS: Seven hundred fifty patients were included in the study. The mean age and preoperative body mass index were 49.3 ± 13.1 years and 50 ± 12.6 kg/m2, respectively. Follow-up was available on 109 patients (61%) at 5 years and on 87 patients (53%) at 6 years. Six patients did not have any follow-up. The average operative time and length of stay were 67.6 ± 27.4 minutes and 1.5 ± .8 days, respectively. The intraoperative, short-term, and long-term complication rates were 0%, 7.8%, 11.7%, respectively. The 30-day emergency room visit, readmission, and reoperation rates were .4%, 1.1%, and 1.1%, respectively. In total, there were 15 (2%) grade IIIb long-term complications unique to LSADI-S. Complete remission of type 2 diabetes was seen in 77% of the diabetic population. At 5 and 6 years, the mean change in body mass index was 17.5 ± 6.9 and 17.6 ± 6.4 kg/m2, respectively. The mortality rate was .5%. CONCLUSIONS: LSADI-S is effective in this retrospective review in achieving good initial weight loss and weight maintenance. Although our data show acceptable nutritional complications, questions still remain because of the retrospective nature of the study.

Internal Hernia Following Primary Laparoscopic SADI-S: the First Reported Case.

BACKGROUND: Internal hernias have not been reported with primary laparoscopic single anastomosis duodeno-ileostomy with sleeve gastrectomy (LSADI-S). This is the first reported case of an internal hernia following primary LSADI-S and its surgical treatment. CASE PRESENTATION: In this video case report, we present a case of a 54-year-old woman with a BMI of 53 kg/m2 who had undergone a primary LSADI-S for morbid obesity. The patient underwent an exploratory laparoscopy for chronic nausea and bile reflux. At surgery, we discovered a Petersen's hernia defect, which was corrected by untwisting the bowel and sewing the space closed (video). A Braun enteroenterostomy was also performed. CONCLUSIONS: An internal hernia following LSADI-S is rare, despite the unclosed space behind the small bowel mesentery. If they occur, they should not cause ischemia and can be fixed easily using a laparoscopic surgical approach with good postoperative outcomes.

Early Outcomes of Primary SADI-S: an Australian Experience.

INTRODUCTION: Single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) surgery is a modification of the traditional duodenal switch (DS) surgery. SADI-S is relatively a new bariatric surgical procedure and has gone by many names depending on the length of the common channel. In this study, we report our initial experience with this novel technique in the Australian population. METHODS: The medical records of 91 patients who underwent laparoscopic primary SADI-S surgery by one surgeon at a single Australian center from January 2017 through May 2019 were retrospectively studied. RESULTS: Ninety-one patients were identified for analysis. The mean age and preoperative body mass index (BMI) was 46.2 ± 9 years and 43.2 ± 5.7 kg/m2, respectively. The mean operative time and length of stay were 121.8+/- 25 minutes and 1.4 ± 0.8 days, respectively. At 12 and 24 months, the patients lost an average BMI of 15.2 ± 5.2 kg/m2 and 17.2 ± 5.9 kg/m2, respectively. The short-term and long-term complication rates were 4.3% and 0%, respectively. The mortality rate was 0%. Postoperatively, the obstructive sleep apnea, type 2 diabetes, hyperlipidemia, hypertension, and gastroesophageal reflux disease resolution rates were 94, 94, 75, 68, and 13%, respectively. There was no statistically significant difference between most of the preoperative and postoperative nutritional data. CONCLUSIONS: SADI-S appears to be a safe bariatric surgical procedure with favorable outcomes at 2 years in the Australian population.

Bowel Reconstruction to Treat Chronic Diarrhea and Hypoproteinemia Following Single Anastomosis Duodenal-Ileal Bypass with Sleeve Gastrectomy: a Single-Site Experience.

BACKGROUND: Single anastomosis duodenal-ileal bypass with sleeve gastrectomy (SADI-S) is a modification of the biliopancreatic diversion with duodenal switch (BPD-DS) surgery. A concern with SADI-S is chronic diarrhea and hypoproteinemia. Common channel lengthening (CCL) is a surgical procedure to increase absorption in the small intestine to decrease diarrhea. OBJECTIVES: The aim of this study was to assess the occurrence and treatment of hypoproteinemia and chronic diarrhea with CCL following SADI-S surgery. SETTING: Private practice in the USA. METHODS: Patients were included if they underwent SADI-S from September 2013 to March 2018 and following surgery underwent CCL. RESULTS: Average operating time for laparoscopic CCL is 56.5 ± 4.6 min. The average bowel movements for the eight patients before laparoscopic CCL were 9.1 ± 4.7 a day. After the surgery, the bowel movements were reduced to 2.6 ± 0.4 a day. This difference was found to be statistically significantly different (p = .002). The two patients experiencing hypoproteinemia improved protein levels following CCL. CONCLUSION: CCL is an effective way to treat symptomatic chronic diarrhea after SADI-S when conservative treatments have failed.

Does the future of laparoscopic sleeve gastrectomy lie in the outpatient surgery center? A retrospective study of the safety of 3162 outpatient sleeve gastrectomies.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is a safe and effective procedure that can be performed as an outpatient procedure. OBJECTIVES: The aim of the study was to determine whether same-day discharge LSG is safe when performed in an outpatient surgery center. SETTING: Outpatient surgery centers. METHODS: The medical records of 3162 patients who underwent primary LSG procedure by 21 surgeons at 9 outpatient surgery centers from January 2010 through February 2018 were retrospectively reviewed. RESULTS: Three thousand one hundred sixty-two patients were managed with enhanced recovery after surgery protocol and were included in this analysis. The mean age and preoperative body mass index were 43.1 ± 10.8 years and 42.1 ± 7.1 kg/m2, respectively. Sleep apnea, type 2 diabetes, gastroesophageal reflux disease, hypertension, and hyperlipidemia were seen in 14.4%, 13.5%, 24.7%, 30.4%, and 17.6% patients, respectively. The mean total operative time was 56.4 ± 16.9 minutes (skin to skin). One intraoperative complication (.03%) occurred. The hospital transfer rate was .2%. The 30-day follow-up rate was 85%. The postoperative outcomes were analyzed based on the available data. The 30-day readmission, reoperation, reintervention, and emergency room visit rates were .6%, .6%, .2%, and .1%, respectively. The 30-day mortality rate was 0%. The total short-term complication rate was 2.5%. CONCLUSIONS: Same-day discharge seems to be safe when performed in an outpatient surgery center in selected patients. It would appear that outpatient surgery centers are a viable option for patients with minimal surgical risks.

Mid-term 4-Year Outcomes with Single Anastomosis Duodenal-Ileal Bypass with Sleeve Gastrectomy Surgery at a Single US Center.

BACKGROUND: Single anastomosis duodenal-ileal bypass with sleeve gastrectomy (SADI-S) is a modification of Roux-en-Y duodenal switch (RYDS). Long-term data on this operation is lacking in the literature. We reviewed our mid-term data of this RYDS modification. PURPOSE: To analyze the outcomes with SADI-S at 4 years. METHODS: Data from patients who underwent a primary SADI-S procedure performed by three surgeons at a single institution from June 2013 through February 2018 were retrospectively reviewed. All revision bariatric surgeries were excluded. Regression analyses were performed for all follow-up weight loss data. RESULTS: There were 437 patients in our database. The pre-operative mean body mass index (BMI) was 49.8 ± 8.8 kg/m2. The 30-day complication rate was 7.7%. The 30-day readmission, reoperation, and mortality rates were 1.8, 1.3, and 0.2%, respectively. The long-term complication rate was 10.9%. Seventy-nine patients were 4 years post SADI-S surgery and follow-up was possible for 44 patients (55.7%). At 4 years, patients had an average change in BMI of 18.1 ± 6 units with an excess weight loss (EWL) of 85.7 ± 27.3%. At 4 years, 97.6% patients were able to maintain HbA1c < 6% with or without the use of diabetic medication. There was a statistically significant difference between most of the pre-operative and post-operative nutritional data. CONCLUSIONS: SADI-S is a safe and effective procedure in both short- and mid-term data points. Diabetes resolution and weight loss appear similar to traditional RYDS and better than RYGB.